My Rambling on the 'net

PIC-Based Battery Monitor

2011-05-06T11:40:00.002+08:00

My friends, as usual, drove me to craziness again and led me to design, fabricate and test a smart battery monitor... The usual blinking lights and so on... This prototype is using an 18-pins PIC but for the real runs, an 8-pins PIC is more than sufficient... I happen to have the 18-pins PIC in my junk box... yeah, it's a very big junk box... :)

Battery Monitor - Revisited

2011-04-26T08:31:00.003+08:00

After my initial try with the battery monitor, I wasn't too happy as it wasn't simple enough to use. The original circuit need to be switched on and off in order to avoid draining the battery.

Here comes version 2. The LED will only come on when the voltage drops below the set threshold. While connected to the battery in the 'LED OFF' state, the circuit will draw less than 1mA which is likely to be much lower than the LiPo self-discharging current... As such, the circuit can be connected to the battery indefinitely... the LED will only comes on if the voltage drops below the set threshold. The photo above show the old circuit and the new one (which is SMD).

Rechargeable batteries... I'm not a salesman...

2011-04-04T11:11:00.004+08:00

In today's modern age, one cannot run away from buying and buying and buying batteries for all the nice gadgets we have... I've been on that route... Since last 1 year, I've been using the Sanyo Eneloop Rechargeable NiMH battery for my camera's flash and I'm very pleased with it so I'd like to share that knowledge with my friend...

Eneloop battery are regular NiMH battery but can retain it charge for a much longer time compared to standard NiMH batteries... After 1 year, it is supposed to retain about 85% of it charge! No more 'oops, forgot to charge the batteries excuses'... Of course, it's a bit more expensive though... :)

Read a detailed review and test of the battery here for more details...

p/s: I'm not a Sanyo staff :-)

Simple Variable Voltage Power Supply...

2011-03-28T09:05:00.003+08:00

To set the threshold voltage for unit below, a variable power supply is needed... Below is a simple one based on the industry workhorse, LM317... Click image to go to source site...

LM317 is a very versatile component... Download the datasheet here to see other applications using the same component...

[Updated] New Hobby... New Tinkering... Lipo Battery Monitor...

2011-03-24T09:58:00.005+08:00

I recently started playing RC helicopters... nothing fancy... just beginner models...

As anyone in RC knows, LiPo battery is very sensitive to charging and discharging activities... Charging needs to be accurately monitored and discharging should not be all the way to zero capacity... There are various voltage versus capacity chart on the 'net and plenty of ready of-the-shelf LiPo battery monitor on the market... Me being me again, I wanted a simple LiPo voltage monitor for my RC usage (and friends using LiPo to replace obsolete battery on their amateur radio handies)...

The following circuit was found on the 'net... It can be wired point to point or a small PCB could be made for it... I'm yet to test it out (waiting for parts) but if it proves practical, I'll probably go with SMD route to make it as small as possible... I'll replace R1 and R2 with trimmer so that the unit can be made universal to monitor any batteries... btw, the estimated parts cost is around RM1.00 :) ... so stay tune...

[Update]... Parts arrived already...
Here the photo of the unit I made over the weekend to show the size next to a 7.4V 850mAH LiPo battery... Trigger voltage is adjustable using the trimmer... As set, the unit takes about 10mA when LED is on (voltage is at or above the set threshold)...

Aahhh... it's that time again... thinking time...

2010-05-26T18:22:00.002+08:00

Found this video while surfing the 'net.
Got me thinking... We all, in fact everything in the universe and beyond, are nothing but nothing...
Watch the movie, ponder about it, reflect on it and chart your destiny...

LHC is alive... and so are we...

2010-04-01T12:17:00.003+08:00

The large Hadron Collider (LHC) has successfully managed to perform what it was supposed to do... a 7TeV proton collision... (no no, not the Wira, Perdana, or the likes)...

Yet, we are still here... the earth hasn't been swallowed by black hole (yet?)... anyhow, more news on the net.. one of it is here ...

Some light reading (for some)...

2010-01-12T08:12:00.002+08:00

On the Origin of Gravity and the Laws of Newton

Starting from first principles and general assumptions Newton's law of gravitation is shown to arise naturally and unavoidably in a theory in which space is emergent through a holographic scenario. Gravity is explained as an entropic force caused by changes in the information associated with the positions of material bodies. A relativistic generalization of the presented arguments directly leads to the Einstein equations. When space is emergent even Newton's law of inertia needs to be explained. The equivalence principle leads us to conclude that it is actually this law of inertia whose origin is entropic.

Ha ha... you got this far... so here's the full theory...

My wish for this Christmas...

2009-12-03T13:32:00.002+08:00

Parabolic Reflector for USB 3G/EDGE/Wifi

2009-10-26T13:01:00.004+08:00

I recently started using wireless broadband for my mobile internet access. While I was able to get around 1mbps at my office location, the coverage doesn't extend well to my housing area. I have to be contented with EDGE. EDGE would still be okay for my occasional internet need at home but the signal strength is so bad that I could barely make any connection.

So, again, I'm off to the internet for a solution. A full parabolic dish would probably be an overkill for my need so I settled with parabolic reflector instead. After about 20 minutes on the PC for the parabolic design and g-code generation; and another 20 minutes on the Sherline CNC, my simple parabolic reflector was born. Made from acrylic (left over from other projects, thus the multiple colors), the reflective portion is covered with the kitchen grade aluminum foil.

As shown above, the reflector can be set vertically on the table or attached to a normal handphone holder bracket for more articulated positioning (below).

How did it perform?
I have no way of measuring true dB improvement but the signal meter on the software provided went up by 2-3 bars when the reflector is used. For now, I could utilise EDGE almost full speed (around 200kbps) without fail. Happy at last... :-)

Duit Raya... from Google AdSense

2009-10-08T12:14:00.004+08:00

As always, me as skeptical as ever... wondering whether Google will actually make the payment since I've heard various horror stories regarding the AdSense payment. Well, my balance finally hit the magic USD100.00 minimum required for payment and I anxiously waited for the moment.

After typical processing time line, I check my account at AdSense again and it was stated that payment has been issued (without any email advising me on the matter). To avoid possible embarrassment at the bank, I called up Western Union customer care to check if the payment is valid and genuine. The Philippine lady who answered my call confirms it.

So, today I went to the bank. The first time I ever receive any money via Western Union. Rushed to the nearest CIMB Bank, fill up a form, waited for the counter to call my number and voila... the proof in sight...

Cheap interactive screen with WII Remote

2009-09-28T08:58:00.003+08:00

Found this video on the net... Did some surfing on the subject... maybe my next project... hmmm.... Link is here

My HariRaya Gift Arrived... ER16 Chuck for my Sherline

2009-09-18T08:08:00.004+08:00

Most people get Hariraya greeting cards around this time but not me... :-)

Just took delivery of my new ER16 MT1 chuck and collets yesterday from CTC Tools (eBay Seller). Fixed it to my Sherline and seems to be okay. Just needed to get an M6 x 100 screw to anchor the chuck to the Sherline spindle then I'll be set... No more hammering to get the chuck out... Just twist the collect holder and my bits are free... After fixing the ER16 chuck, I'll loose around 1.5" of vertical travel but that's not much of a concern for me... Photos show the new ER16 chuck next to the various earlier (Sherline) milling collets, drilling chuck and endmill holders.

To all the muslims of the world, Eid Mubarak. May Allah bless us and the whole world. Let us live in peace and harmony...

To my friends, my sincere apologies for any wrongdoings in the past, present and future. Have a safe and wonderful Hariraya.

Naza Sorento 2.5l CRDi Fuel Consumption Chart

2009-09-01T10:34:00.003+08:00

Posted here for reference my the Sorento buddies... Click chart for detailed view...

Bye Bye Ferric Chloride...

2009-08-25T09:43:00.007+08:00

IMPORTANT UPDATE: 28th August 2009
************************************************
Upon further reading, I learn that the HCl + H₂O₂ solution have short shelf life. So I decided to test my solution. True enough, it wasn't able to etch any PCB. I'm not sure what's the cause yet but my guess is that I need to add the 'starter' copper immediately after mixing the HCl + H₂O₂ to stabilise the solution so that the solution is CuCl₂+ H₂O instead of HCl + H₂O₂.
Will update the result after the experimentation... :-)
This site has very complete and full of technical information on the subject.
************************************************************************************

After more than 20 years relying on Ferric Chloride as my etchant for PCB, I decided to switch to a new solution for PCB etching that promises faster etching, cleaner solution and recycle-able chemicals. After review of several sites on the internet, I decided to go with the Hydrogen Peroxide/Hydrochloric Acid solution.

Photo below shows the starting chemicals, i.e., muratic acid (31.45% HCl v/v) and Hydrogen Peroxide (6% H2O2 v/v). The muratic acid (1 quart, ~950ml) was obtained from Ace Hardware, normally used as cleaning agent. The hydrogen peroxide (450ml) was obtained from a pharmacy.

For the volume of solution that I required and based on the concentration of chemical available, my etchant is made by adding 600ml of the muratic acid to 900ml of hydrogen peroxide yielding 1.5 liters of etchant.

As usual, I added the bubble ring for solution agitation during etching. However, with the new solution, the air bubble also serves as oxidizer, regenerating the solution. Theoretically, I should not need to throw away the solution for eternity. If the air bubbling isn't enough to regenerate the solution, addition of small amount of new muratic acid should be able to replenish the consumed ions...

Better explanation of the chemistry involved at this site. Excerpts below:

Here's what's going on chemically:

Before there's much copper dissolved in the solution, Cu + 2 HCl + H₂O₂ -> CuCl₂+ 2H₂O is the dominant net reaction. That is, the extra oxygen in solution from the peroxide is oxidizing the copper metal, in presence of the acid, to make copper (II) chloride. That's our starter etchant. The resulting CuCl₂ shoud be a nice emerald green color.

After you've dissolved a lot of copper into the solution, and used up all the peroxide, the copper chloride does most of the etching for you: CuCl₂ + Cu -> 2 CuCl. That's the end etchant.

Eventually you etch so much that you convert all the CuCl2 into CuCl, which doesn't dissolve copper (and is a yucky brown color). As long as you've got enough acid in the solution, you can simply add more oxygen to re-oxidize the copper(I), making more copper(II) chloride and water: 2 CuCl + 2 HCl + O -> 2 CuCl₂ + H₂O. And then you can etch again.

Bottom Line:

Two things to maintain: CuCl₂ levels and acid levels.

CuCl₂: After all the peroxide is used up, and the solution starts turning brownish, you'll have to add oxygen to regenerate the solution again: toss in a few more capfuls of peroxide or bubble air through the solution or swirl it around vigorously, or just pour it into an open container and wait. It's easy to tell when you're ready to etch again, because the solution turns green.

It's also impossible to add too much oxygen by adding air, so bubble/swirl to your heart's content. If you're using peroxide to add oxygen, be sparing -- a little goes a long way, and it's mostly water so you're diluting your etchant by adding it.

Acid: Note that HCl is being consumed in the starter etchant and the regeneration reactions. So we're going to have to add a bit more acid as time goes by. If you notice that it's harder to re-green your brown etchant, it's probably time to start thinking acid.

RFM-USB Interface

2009-08-03T08:35:00.003+08:00

The photo shows the RFM-USB interface made using double-sided, non-PTH PCB. As can been seen, the top layer components pads are not soldered. This approach result in higher number of vias but simplify soldering of the double-sided board. 100% homebrewable...

During testing, another problem was identified. The RFM12B has a max VCC of 3.8V so I used a 3.3V regulator for it and simple voltage divider on the signals from PIC to the RFM. Then, the output from RFM12B are wired directly to the PIC. Upon measurement, the voltage of the RFM12B output max to about 3.7V. Unfortunately, the PIC input (SDI) has a schmidt trigger thus requires minimum iput of 0.8xVCC. At 5V, that translated to 4V... thus higher than what the RFM12B can deliver. Hmmm... more thinking/decision required:

Run the RFM12B at USB voltage (normally below 5V) which is over the design max but below the absolute max (of 6V).
Replace the RFM12B with RFM12 (meant for 5V) and run the interface at USB voltage.
Run the PIC at 4.2V (minimum for PIC18F2550) via voltage regulator or simple diode voltage drop.
Add level translator on the RFM12B output to bring the output to VCC.

I'm using option 1 for now (using my previous board). The above new board still works since the VCC from USB on my PC is around 4.6V. Thus 0.8x4.6V->3.68V, something the RFM12B still can managed. For actual production, I'll use option 1 and 2, i.e., run everyting at VCC from USB and replaced the RFM12B with RFM12.

Updated RFM12B-USB Interface

2009-07-30T10:24:00.002+08:00

After review of the first RFM12B-USB interfacing, I noted that I'm driving the RFM12B over the design spec wrt the power supply. RFM12B is designed for 3.6V max VCC whereas USB supply typically is near 5V. As such, I've redesigned the interface to be 5V friendly with on-board 3.3V regulator and voltage dividers on the signal lines.

This board is double sided but does not need plated through holes as no top side soldering required on the components (except for vias). There is a technique on how to do that with Eagle which I may cover in next postings...

Over the weekend... RFM12B-USB Interface & CNC Work...

2009-07-27T13:53:00.002+08:00

Had some spare time over the weekend so I decided to move on on my wireless data logger project. The slave/master communication was ironed out earlier. At least I know that data are being transmitted and received correctly because the checksum is valid. I had no way of knowing what actual data was transmitted because I had no visibility on the communication.

So, I decided to make a small RFM12B-to-USB interface as shown below. With this unit, I should be able to sniff the communication over the air and display the capture information on a PC. Yet to do some codings for it though, for the PIC and the PC. Not only the interface allows me to sniff the traffic, I can actually make it behave either as slave or master. That will be helpful in testing the configuration and logging protocol later on.

I also spend few minutes on my Sherline CNC to mill out some holes for a friend. He wanted to mount the digital volt and ammeter to the casing... so my CNC was summoned to the rescue... In photo below, the meters have not been flush mounted to the casing... once flushed mounted, it's gonna be pain in the *&^ trying to take it out because of the very tight fit...

Checked your VISA statement lately...?

2009-07-17T08:16:00.004+08:00

NEW YORK (CNN) -- A technical snafu left some Visa prepaid cardholders stunned and horrified Monday to see a $23,148,855,308,184,500 charge on their statements.

Josh Muszynski noticed the 17-digit charge while making a routine balance inquiry.

That's about 2,007 times the size of the USA national debt.

Josh Muszynski, 22, of Manchester, New Hampshire, was one Visa customer aghast to find the 17-digit charge on his bill. Adding insult to injury, he had also been hit with a $15 overdraft fee.

He noticed that his debt exceeded the world GDP while making a routine balance inquiry on his online Bank of America account. According to his statement, he had spent the profound sum in one pop at a nearby Mobil gas station -- his regular stop for Camel cigarettes.

"Very, very panicked," he jumped in his car and sped to the station.

Full story here...

Farnell Did It Again...

2009-07-15T11:03:00.003+08:00

As mentioned in my previous blog, I bought a tube of 22 pcs of PIC16F690 for less than RM85. As I indicated, PIC16F690 has very similar functionality with PIC16F88. However, the price was 75% cheaper than PIC16F88 (RM85/22 vs RM336/25). Well, Farnell revised the price today to RM242 for tube of 22. Previously, I also bought a tube of 25pcs of PIC16F88 for RM150 and a week later, Farnell revised it to the current price of RM336 for 25pcs. Hmmm... maybe I should have kept my mouth shut...

Moral of the story... if you see something really cheap at Farnell, it probably is. So, if you want it, buy it quick... before they revise the price upward...

The enclosure for datalogger

2009-07-15T08:20:00.002+08:00

The enclosure above, with access panel for 2 x AAA battery, will be used for the datalogger. Photo posted for 9w2dtr for the PCB design reference... :-)

Creative Problem Solving

2009-07-10T12:34:00.006+08:00

In trying to figure out the best protocol for my wireless multinode data logger, I needed a way to visualise the problem. For those interested, here's the problem statement... simplified to everyday scenario... :-)

A sales department has a BOSS and 16 STAFF

Objectives:

BOSS wants sales update every 1 day.
STAFF should MAXIMISE time outside of office.

Conditions:

Staff updates can be done inside the office only.
No way to contact STAFF once they are outside of office.
The BOSS and staff do not use watches. They only have timer/stopwatch (95% accuracy) thus statement "Update me at 3.30pm" cannot be used, but "Update me 30 minutes from now" is acceptable and the timing may be off by 5%.
Only 1 party (BOSS or STAFF) talk at any given time.
The updating only takes 2 minutes!
BOSS and STAFF works 24-hours per day.

Problem:

Find the most effective way (scheduling or otherwise) to get sales update on time and maximise STAFF time doing sales.

Update: Cytron UIC00A Limitations

2009-07-09T12:34:00.004+08:00

Further to my earlier blog that I was having problem to program PIC16F88 when MCLR is disabled and using internal clock as system clock, I just come across the following note added to the (new?) UIC00A User Manual from Cytron. Please take note of the limitations. BTW, the PIC is not spoiled.

RFM12B+PIC: Let's sleep... separately....

2009-07-09T07:54:00.003+08:00

As typically done, to conserve power, electronic devices are put into a 'sleep' mode. For the RFM+PIC setup I had mentioned previously, the same method is employed. The PIC commands the RFM to go into sleep mode but preprogrammed the RFM to wake up in about 5s... very very short nap... after the RFM is commanded to sleep, PIC commanded itself to sleep indefinitely until awaken by something...

After the 5s nap, RFM will wake up (5% accuracy) and will pull the nIRQ line low. The nIRQ line is connected to one of PIC 'interrupt-on-change' pin. The change in voltage level wakes up the PIC and it will continue to execute exactly where it falls asleep.

RFM Slave Testing Units

2009-07-08T12:14:00.004+08:00

In order to test RF module to module communications, I needed simple boards that could easily be made and programmed. Also, considering the future use for the module, I needed to find a suitable PIC microcontroller to do the job... Final selection was PIC16F690... it has all the bells and whistles, seemed to be as powerful as PIC16F88, but surprisingly 75% cheaper. Not sure if this is another Farnell incorrect pricing but I've gotten myself a tube of 22... :-)

Initial test has been completed, after the addition of more white hairs to my head. The module could send and receive packets correctly. I'm now focusing on how to minimise power consumption as we wanted the module/PIC to run for about 6-months with a simple AA (or AAA) batteries. Once that is solved, I'll move on to developing suitable protocol for master/slave monitoring requirement.

RF Transceiver Module...

2009-06-24T08:58:00.004+08:00

As mentioned by 9W2DTR, the RF transceiver modules we ordered have arrived. It's a 433MHz module capable of max speed of around 115 kbps, tx power of 7dBm and SPI interface.

Since I'll be doing my development on a prototyping board, I needed a way to mount the module. The module's headers are 0.5mm, 2.0mm pitch whereas a standard prototyping boards are 0.1" pitch. A quick clicking on Eagle, and a few minutes later, the adaptor was born. Photo above shows the RF module mounted onto the prototyping adapter and it is sitting on top of the Futurlec PIC18F4550 development board. The 0.1" headers are reverse mounted on the PCB, i.e., the header protrude on the solder side instead of the component side. The loose module and adapter PCB are infront of the mounted module.

Photo below shows how the module looks once mounted to the prototyping board. There are still two (2) holes on either side of the headers to allow for jumper wires.

High voltage and high current equal to...

2009-06-23T11:44:00.002+08:00

some fun...

After my capacitor charger worked as intended, I decided to have some fun with some solder lead and aluminum foil... here's a video of what happened to an ordinary aluminum foil when subjected to the charged capacitor... the 5mm strip instantaneously melted with beautiful spark... too bad it was too fast for my normal camcorder...

High voltage and high current are very dangerous... goes without saying... extreme caution is mandatory...

This is weird, but interesting!

2009-06-17T18:01:00.002+08:00

fi yuo cna raed tihs, yuo hvae a sgtrane mnid too

Cna yuo raed tihs? Olny 55 plepoe out of 100 can.

i cdnuolt blveiee taht I cluod aulaclty uesdnatnrd waht I was rdanieg. The phaonmneal pweor of the hmuan mnid, aoccdrnig to a rscheearch at Cmabrigde Uinervtisy, it dseno't mtaetr in waht oerdr the ltteres in a wrod are, the olny iproamtnt tihng is taht the frsit and lsat ltteer be in the rghit pclae. The rset can be a taotl mses and you can sitll raed it whotuit a pboerlm. Tihs is bcuseae the huamn mnid deos not raed ervey lteter by istlef, but the wrod as a wlohe. Azanmig huh? yaeh and I awlyas tghuhot slpeling was ipmorantt!

Eagle Training Session - Confirmed Date

2009-06-17T14:48:00.007+08:00

Further to the earlier blog on training/familiarization on Cadsoft Eagle, the followings are the update:

Venue: Jalan Klang Lama, Kuala Lumpur
Date: 4th July 2009 - 9.30am to 4.30pm
Participants: 9W2DTR, 9W2BON (+4 SWLs)
Notes: Participants should bring own notebook for hands-on session. You may wish to download and review this tutorial prior to session.

Any others, please let me know early so that we can make proper arrangement.

MilliOhm DVM Adapter

2009-06-16T12:49:00.005+08:00

My recent works with SMPS entails winding of coils and, sometimes, current sense resistor which normally is very low in value. Decided to make the above adapter to measure low resistance which cannot be done using standard DVM. Yet to make it but will update on the usability later. Would be helpful also in tracing for PCB or winding shorts, etc...

2009.06.18 Update: The adapter worked as expected. The only issue is that the current limit resistors need to be 'adjusted' based on the LM317 used. LM317 reference voltage is guaranteed to be between 1.2V to 1.3V. If the resistors are calculated based on 1.25V, maximum possible error is around 4%. It's best to tune the resistor using a digital ammeter. Also note that circuit also measure probes resistance. As such, you need to deduct the voltage drop when the probes are shorted in order to get the actual resistance... If you set the current to 10mA then resistance is 1 milliOhm per 1 milliVolt.

Maybe I program a PIC for that and LED displays later... :-)

SMPS Journey continues...

2009-06-15T08:56:00.002+08:00

Last week I was working on high voltage, high power SMPS using the push-pull topology. It worked well as I could charge a 2mF capacitor to 375V in about 5s. Later I had the urge to try out another design based on flyback topology. It manages to achieved the same thing but with simpler setup. The main difference I noticed is that the transformer is now warm whereas in the push-pull topology, the transformer show no temperature rise at all...

Now.... what am I gonna use them for... hmmm....

A baby coil winder was born...

2009-06-15T08:45:00.004+08:00

Although the coil winder only had a few weekends at may house, it manages to give birth to a new baby winder as shown below... :-)

Made from an old RC servo motor, the baby winder has smaller shaft (M6) thus I could wind smaller cores. It's a simple setup. The servo electronics was gutted and the power is connected direct to a power supply. The on-off switch is there to control the baby during winding. The bolt was sandwiched between two plastic plates (courtesy of my cnc) and fixed with epoxy. The shiny aluminum foil is for me to count the number of revolution. The setup is running at 60rpm with a 6V supply.

Cadsoft Eagle Training/Familiarization Session

2009-06-10T16:01:00.003+08:00

I've got a few friends asking me to guide them on how to use the Cadsoft Eagle for schematic capture and PCB production. So, in the spirit of sharing, I'm planning to organize a training/familiarization session on the software.

The session will be held in a friend's office, during a weekend. The room will be air-conditioned with LCD projector available. However, participants need to bring own computer to participate on the hands on exercises.

The basic areas to be covered are: Schematic capture, converting it to PCB, doing some electrical rule check and design rule check, and if time allows, we'll touch on creating own library.

If you are keen, please drop me a line either by the chat box or comments on this blog.

Meanwhile, the software is at Cadsoft and here is the product tour.

Time for some low tech - good use device...

2009-06-08T08:46:00.002+08:00

Working on the SMPS means winding my own transformers. Terms like EI-25, ETD-29 started to make some sense to me. Had the opportunity to shop with the devil the other day and I ended up picking up this piece of equipment for about RM100. It's a coil winder... the dial will tell you the number of turns the bobbin make. Works well, simple and effective. The only problem is that the winder shaft is about 10mm diameter whereas all my project cores are small thus would not fit the shaft... hmmm... may be time to see silver hair, 9M2CF, to put his lathe to work... :-)

SMPS Journey Update

2009-06-08T08:34:00.003+08:00

After several countless nights without REM sleep and tons of downloads from the net, I finally managed to get my SMPS to work as intended. Final board shown below. Few learning points for me on SMPS.

The rectifier diode recovery time is a critical parameter. Consider the switching frequency in diode selection. Slow diode will result in short circuit like behaviour on the secondary.
Use of snubber circuit on the mosfet help to reduce the voltage spikes.
Filtering and emi protection for sensitive digital circuit.
Capacitor explodes with big bang... :-)

Quick, Cheap, Reliable UV Exposure Box...

2009-06-03T13:23:00.002+08:00

In the spirit of homebrew and DIY, the following UV exposure box is the easiest way to do it... congratulation to 9M2IBR for the journey... click image for link...

Switching Mode Power Supply... my new frontier...

2009-05-29T12:37:00.003+08:00

Ever since I started playing with electronics, I have never ventured into switching mode power supply (SMPS) arena... Linear regulators have served me fine since my projects are low power and low voltage.

For my new project, still in development, I needed to charge a large capacitor bank to 400V. More over, it needed to be portable thus ruling out the use of mains transformer. So, with it, I have to learn all the complexity of SMPS. Below is my test board... so far working but require significant fine tuning to improve efficiency and charging speed.

PCB UV Exposure Box DIY

2009-05-26T10:21:00.002+08:00

Since some of you are wondering how my UV exposure box looks like, I shot the photos below for your viewing pleasure. The unit uses 2x8W UV lights obtained from Farnell. The box was fabricated from HDF board (the same board used by picture frame shop) and the exposure area was lined with aluminum foil to improve reflectivity. The tubes are about 4" apart and 4" below the frosted glass. The frosted glass is intended to diffuse the UV so that there are no UV bright spots.

I've also made a simple PIC-based timer to time the exposure. Using the Kingsten PCB, exposure is 90 seconds. I use inkjet transparencies to make the exposure film. So far, I've managed to get 0.25mm track with 0.25mm separation with no problem. PCB are developed using NaoH developer and etches using Fe2Cl3. From exposure to PCB ready to drill in less than 20 minutes. I'll never go back to iron-on method... :-)

Amateur Radio without Hand-Free

2009-04-24T11:46:00.005+08:00

Hello again to all amateur radio in Malaysia.

Over past few eons we continue to hear conversations and arguments whether it is illegal to use our portable or mobile unit while driving. Well, one good soul, no not me, finally look up the relevant law. Below is extract of Road Traffic Rule 1959 regarding the subject (amended in 1996). Also note that Rules 17D, which talks about exemption, did not list any with respect to this topic. BTW, here's what ARRL (USA) has to say on the topic (January 2009)... PDF File

Rule 17A. Prohibition on the use of hand held telephone.

(1) No driver, whist driving a motor vehicle on a road, shall use, or attempt to use, a hand-held telephone or any other communication equipment unless it is used through a hand-free kit.

(2) Any person who contravenes subrule(1) shall be guilty of an offence and shall, on conviction, be liable to a fine not exceeding one thousand ringgit or to imprisonment for a term not exceeding three months and, in the case of a second or subsequent conviction, to a fine not exceeding two thousand ringgit or to imprisonment for a term not exceeding six months or to both.

[Ins. P.U.(A) 378/1996]

My Sorento Fuel Consumption Chart

2009-04-16T14:05:00.003+08:00

For the benefit on some of my Sorento buddies, here is my Sorento fuel consumption chart for reference. Click image for fullsize chart.

Let's save some fuel...

2009-03-19T10:00:00.004+08:00

The crude oil price is back to the normal range and more and more cars are crowding the roads now. Some of you already heard about the hydrogen supplemented fuel where tiny amount of hydrogen is being feed to the petrol/diesel engines. The hydrogen is typically generated using a simple electrolysis process where current is passed through water to split it into hydrogen and oxygen gas. Some call this gas hydroxyl rather than hydrogen because it also contains oxygen. I spare you the technical details as millions of hits will return if you type hydroxyl in google. On the same note, I'm not going to dwell into the never ending debate whether this approach will actually save fuel. Ask google for that... :-)

Here are some photo of the most recent installation done by my colleagues. The vehicle is Perodua MyVi. The vehicle is 3-years old and already clocked around 150,000km. Pictured below is the homebrew electrolysis unit consisting of two cell and a bubbler. Noticed the small box on it.... Yeah, it's my digital PWM controller blogged earlier. All system go, working as planned.

The tubing brought from the rear of the car to the air intake filter.

It's been a while...

2009-03-06T08:08:00.002+08:00

This blog was started in June 2007 as a mean for me to share some info with my friends and others with similar interest. Over the past one and a half year, I've met several new friends here, share some ideas, kick some punches, shed some tears...

I just want to thank all those who peruse this blog.
I know, some of you have no clue at all to what I'm writing here... :-)

Yesterday, this blog hit the 20,000 visits mark. I think it call for a celebration. I never expected that many hits for a much like a personal technical diary.

Again, thank you all...

New Digital PWM Controller for HHO Hydrogen Cell...

2009-02-24T12:14:00.003+08:00

My analog current controller (not blogged) has been working okay thus far. As always, some of us are never satisfied unless they see some LEDs blinking somewhere to reconfirm that the unit is working. So I embarked on making a current controller that's digitally based so that I could display some functions as well as eliminating the need to open the casing to set the current, etc.

This new controller do that. It displays the line voltage, the current draw, the PWM frequency, the current limit and the cut off voltage. Setting the current and cut off voltage is done by a single switch brought to the front of the unit.

Once set, the unit will try to achieve/maintain the set current by varying the PWM frequency. It will also monitor the line voltage and if the voltage drop below the setpoint, it will switch off the PWM. Photo show the test unit displaying the line voltage... kewl... don't you think... :-)

CHEAP, effective, convenient SMD container

2009-02-19T10:10:00.003+08:00

All electronic hobbyists know surface mound devices are the way of the future... small, cheap but really pain in the ^%*& for homebrew and DIY. But with enough patience and courage, no mountain too high attitude, it can be done...

Because the SMD are so tiny, I needed a way to store them... After much searching for suitable solution, I came across the 'Weekly Pills Organizer' at a local store that cost only RM5 each. Bought a whole bunch of them, labelled using self adhesive sticker and now neatly stacked near my workbench...

There are several type of the weekly pill organizers. Get the one like mine below for the following reasons.

It's cheap, translucent and not pre-printed. Simpler for you to print and stick your own.
The unit comes with the large storage box. You can group your SMD together; resistors, capacitors, etc... Also, it serves as double-lock so that it is more robust... less likely to open by mistake...
The smaller unit is detachable. Makes your live easier when you want to take the devices. If you drop it, only the 3 containers are affected... not the total 21 :-(

CAUTION: To friends using the PIC16F88

2009-02-17T10:33:00.003+08:00

Just a short cautionary note to all friends using the Microchip PIC16F88 chip.

If you use Internal Oscillator as your system clock, please avoid using the MCLR pin as input, eventhough PIC16F88 can be configured that way. The reason for this caution is that, once your program the PIC, it is almost imposibble to re-program it. The PIC will start executing once it's powered and that will some how cause the programming timing to go haywire.

Do take note.
I've wasted two PIC16F88 before looking this problem up on the 'net :-(

Electronics without schematic...

2009-02-17T09:46:00.006+08:00

Eventhough you don't understand anything about electronics, you can still appreciate the outcome... for this project, you don't need to know the difference between resistor and capacitor and transistor and translator... just some glue and lot's of creativity... image from www.sparkfun.com

Blink Blink Revisited

2009-02-10T14:06:00.003+08:00

For those who got good memory, you may recall this project I did earlier... it had gone through multiple iterations... from LED replacement to several code changes. The most recent is the request to change from the large LCD based interface to a smaller unit... test unit is done, awaiting test with my friend...

The original interface...

Newly designed interface... just LED to echo the state of the LED banks... smaller box with RJ-11 connector... can just use any 4-wire telephone cables... :_) Overall size about 4x3 inches...

Icom OPC-478 Programming Cable

2009-02-03T11:12:00.006+08:00

Hello all,

I've had the Icom IC-2200 2m transceiver for the past few month for my base unit. I haven't been using it for a long while as I seldom QSO when I'm home... too many other things to do... Lately several new repeaters have been on the scene and as always... read as being lazy... I take not effort to update the IC-2200 frequencies.

Lucky for me, there's another station who got nothing to do other than amateur radio and, better still, he is also using the IC-2200... read as cloning time... Though the IC-2200 allow cloning using a simple stereo cable, I wanted to edit some of the frequencies before loading it on my unit... the hunt for suitable arsenal begins...

To do what I wanted to do... three things are needed... 1) The Icom OPC-478 programming cable, 2) The right software, and 3) a USB to RS232 convertor since my PC doesn't have built in serial port. Found the circuit for OPC-478 equivalent on the net so I got that done. Found the right software... somehow :-) I also got the USB to RS232 convertor

I'm ready right? Nope, as it turns out the USB to RS232 convertor had some compatibility problems... It was detected by my OS but fail to work with the OPC-478... Lucky, I had another converter (another brand) lying around and that unit worked... Conclusion, get USB to RS232 converter that uses the FTDI chip... it seems to be more 'compatible'... how to tell the different? You can't... most packaging do not specify the chip used... :-( Just try your luck... btw, the one that worked was molded with dark grey plastics... the one that does not work was molded using blue plastics... don't know if that helps...

The screenshot of the Icom CS-2200H software...

PWM-Based Current Controller

2009-01-06T08:22:00.004+08:00

A friend was looking for ways to control current flow in one of his projects. As always, MacGyver was approached to find a solution for him. So, MacGyver did just that. Pictured below is a PIC-based, PWM current controller that runs at 70kHz with 0-100% duty cycle varied via the multiturn trimpot. The MOSFET used is supposed to be able to handle about 50A with 0.022ohms on resistance. I don't think it can hit that high without exploding with the current heatsink.

Anyhow, the whole purpose of this board is to ascertain how much current does his project needs. From there, an alternative circuit will be made to cater just for that requirement... No need for fancy PIC, LED and all... That's for later... :-)

MyChicA Video...

2009-01-05T08:37:00.003+08:00

During my initial search for a suitable robot to build, I could not find any Loki-based biped video on the internet... not on youtube and not on metacafe... so... for those seeking to see how a Loki-based biped moves, here the video I took of MyChicA doing forward and slight left turn...

For the moment, MyChicA is walking blind... next to be added will be the IR-based distance measurement system... later possibly a tactile switch under the feet to detect edges... who knows... we'll see how it goes...

MyChicA Biped Robot got a new trainer...

2008-12-31T12:31:00.005+08:00

MyChicA is evolving rapidly... from crawling few days ago, she just recruited a new trainer... yeah, yeah... I had to develop the trainer... Written with Visual Basic, the trainer communicate with MyChicA via RS232 at 9600bps. I decided to slow down the comm speed to allow more processing to be done within MyChicA little brain...

The trainer/tester is meant to control the servos in order to develop the various gaits position for MyChicA. Once the optimum values are found, they will be embedded into MyChicA brain so she can perform those tasks autonomously...

I love holidays... once the new year starts, I'm not sure I have the time to pet my beloved MyChicA and teach her new tricks... :-)

Epson R290 CISS Modifications

2008-12-30T09:07:00.005+08:00

Several sites and youtube videos already showed how to install the continuous ink supply system (CISS) on to the Epson R290 printer. All of them require that the ink cover be permanently removed to allow for the tubings to be installed. That's exactly what I originally did but not without problems.

The CISS that I bought uses soft plastic for the ink catridges thus when placed into the ink compartment, it doesn't fit tightly causing the the electrical contacts to be intermittently broken. When this happens, the printer driver will complain saying that the ink is not Epson original thus refusing to allow any printing. In the beginning, I placed some wood wedge to force the cartridges to snug-fit.

Although it worked, it became an unbearable hassle to me. Furthermore, every time the electrical connection is re-established, the printer will recognize the cartridges as new so the cleaning cycle will start thus unnecessarily wasting the inks. I finally decided to give another method a try. Using cutter, I snip the original cover to make way for the tubings. Once that is done, I refitted the cover back to the original position. Lo and behold, it worked like a charm... no more wooden wedges, no more lose connections... I'm a happy man once again...

MyChicA Got Her Brain and Juices...

2008-12-30T08:58:00.005+08:00

After my fun-filled holidays with the family, managed to put my hands back on myChicA project. MyChicA now has a brain and power plant. The brain is in the form of Microchip PIC16F876A processor running at 20MHz capable of driving 8 servos with about 200ns resolution. It can communicate with host PC on RS232 interface at 19200bps with no problem. Several spare connectors are on board to allow for future expansion and/or experimentation. So far, myChicA can walk forward and backward with no problem albeit a bit jerky. Software improvement is in progress...

MyChicA with the controller board and batteries (4xAA not visible + 9V) installed.

Let the coding begins...

MyChicA Biped Robot... The beginning

2008-12-17T08:59:00.004+08:00

After much consideration, I decided to start with the basic 4-servo biped. Using the concept from Loki as basis, I went on to design my own. Managed to find the time to cut it on my Sherline CNC using 3mm colored acrylics. So far, all the mechanical work is done. Time to dwell into the electronics.

I gave it a name... MyChicA (pronounced my-chi-kar)...

Loki reminds me of a chicken thus my biped is a Chic. The A is for version 1 as I'm sure more siblings will appear :-) Without the electronics and battery, MyChicA could hold it's posture just using the servo mechanical resistance, as shown below.

Will be updating the progress later... not so soon... going on vacation with the family first... :-)

MyChicA and the twin, Loki... :-)

Amateur Radio Reunion Day 2008 (ARRD08)

2008-12-15T10:01:00.007+08:00

Update 2008.12.15: Individual photos can be accessed from Photobucket using this link (ARRD08 Photos)

Just came back from the said event last weekend. Huge turnouts, youngs and 'seniors'... Weather was good albeit a bit too hot...

Below are the contact sheets of the photos I took during the event. Need to find time to upload it to online photo site. Used the opportunities to meet friends and learn how to use the new D80... :-)

Nice... ooohhh... simple BiPed... the Loki

2008-12-10T14:08:00.003+08:00

Still deciding which robot to build first... either the unit posted before this or this Loki... this Loki looks cute... simple to make... less servo... simpler parts... hmmmm

Also for those keen to have a nice toy, the i-Sobot is now available in Malaysia for under RM1000. Very tempting looking at what its can do... check out this youtube video.

New interest... biped (walking) robots....

2008-12-04T11:33:00.003+08:00

I have been always interested in humanoid robots. After buying a cheap one for my kid, I decided to make one for me :-) After the usual search on the internet, the kit from Lynxmotion attracted my attention but the price it more than what I'm willing to pay for... I'm starting the research on the basic mechanical design now and will be updating this blog with my progress... anyone else want to join me? I'll be firing up my CNC again for the frames...

On the topic of white balance...

2008-12-04T10:56:00.004+08:00

With my new D80, I'm back to snapping photos. While browsing an online photography store, I came across a product called 'Warmcards'. The package comes with several colored cards to adjust the white balance of the camera. Ever wondered why people in your home video look pale and uninteresting? The answer lies in white balance. Most professionals adjust the white balance to make the photo/video look warmer. Refer to warmcards website on how to do this. The image below (image from warmcard website).

The original Warmcards package look as follows:

But, as always, in the spirit of DIY, I decided to make my own cards. After a quick search on the internet, I gathered enough information to print my own cards to test out. To my surprise, it worked extremely well (although I have no idea how the original cards would be different). My homemade cards were printed with the EPSON R290 printer on matte, resin coated, water proof paper. I later laminated the back side to stiffen the card. The matte finish minimize reflection, water proof so I can wipe it clean if I needed to... :-)

For those wanting to give it a try, here's my test layout... btw, the CYMK values used are from the internet and not necessarily reflect the values of the original warmcards.

My new toy... Nikon D80 DSLR + Epson R290

2008-11-25T17:06:00.004+08:00

Though the past few months I've been eyeing various things, I ended up getting myself a digital SLR - Nikon D80. I've not played with SLR for more than 10 years... been going around with digital compact camera all this while... Recently, I just got me an EPSON R290 photo printer. The printer is so good that it bring out the deficiencies in my photos from the compact camera. The Nikon D80 should do some justice to the Epson R290...

Good instruction how to solder SMD components

2008-11-03T13:25:00.003+08:00

Once in a while, people ask me how to solder those tiny SMD components like the above... Rather than duplicating what's already widely available on the internet, here's a link to a very good reference...

Reference Number 1: MENY's Backyard (mostly on communications)
Reference Number 2: SMD 101 at Curious Inventor (video)

Hmmm... another temptation...

2008-10-22T08:25:00.002+08:00

The thing about money is that if you have it, or about to have it, our (especially mine) mind become unstoppable in identifying ways to spend it...

Here's my latest temptation... A USB-Based Logic Analyzer from here

Features:

USB 2.0 Cable (5')
Sampling rates up to 24MHz @8 bits
9 ultra-flexible test lead set
9 E-Z Hook XKM Micro-Hook
-0.5V to 5.25V operating voltage
Input low voltage: -0.5 to 0.8V
Input high voltage: 2 to 5.25V
24MHz maximum sample rate
200M samples

Dimensions:

1.6x1.6x0.36"
16g (0.5 oz)

Amateur Radio ReUnion Day

2008-10-21T18:22:00.004+08:00

Extracts:

"Amateur Radio Reunion Day is an event planned to reunite all amateur radios in Malaysia , Mikes, Whiskeys and Short Wave Listeners , regardless of club affiliation. Furthermore, we are also celebrating 80 years of amateur radio in Malaysia. Our Senior 9M are not getting younger and we have lost a few already. This is the time for 9W and SWL to get to know them. So far 20 Mikes from around the country have confirm their attendence."

More details and update at the blog site here Amateur Radio Reunion Day (ARRD)

Looking for sponsor... for a film scanner... :-)

2008-10-10T17:16:00.008+08:00

Looking for a soul willing to sponsor this film scanner to me... really keen on getting one to scan my old negatives... before the digital camera explosion... estimated landed price of MYR1200 through internet purchase... any taker?

Some reviews:

Brief: Quick and Easy Touch Screen Upgrade for Asus EEE 701

2008-10-07T09:03:00.002+08:00

Just found this quick, easy and cheap touch screen upgrade for the Asus EEE PC 701 at dealextreme.com for those keen to do it... Click on image for link...

Eid Mubarak and 'Selamat Hari Raya'

2008-09-26T08:13:00.006+08:00

The Ramadhan fasting month is fast nearing the end and to that, I take this opportunity to wish all the Muslims of the world, Eid Mubarak, or in my native language 'Selamat Hari Raya'. May God be pleased with us and may world peace becomes a reality.

Aspire One Modding...

2008-09-26T08:03:00.002+08:00

Few of my friends have acquired the Acer Aspire One UMPC and now starting to wonder how to hack it for various purpose... there goes the warranties... :-)

Here's a quick link to tnkgrl never ending mods and hacks... this one is specific for Acer Aspire One...

144MHz FoxHunt Transmitter - Revisited

2008-09-18T08:29:00.004+08:00

Hello again all,

Over the last few days, several people have asked me for more details about the Foxhunt Transmitter project that I did earlier. So, in the spirit of sharing, here's the link to the schematic and component layout as well as the compiled code for the microcontroller.

144MHz Foxhunt Transmitter Details

Happy testing...

And time passes by...

2008-09-04T13:35:00.003+08:00

Hi all,

It's been more than a month since I last wrote anything here... I'm still alive and kicking... Ramadhan is here too so schedule, and the pocket, will be much constrained...

I loss a dear friend few days ago. He was a senior member of the local amateur radio community who goes with the callsign 9M2DS... Lovingly called Pak Dollah by the gang... As other sites already pay tribute to him, I'll just provide the links here...
From UNIARM
From MARTS KLSP
My last project, the LED Blinkers had some problems that need real rectifications:
- The LEDs burnt out and some of them operate intermittently. I believe this is due to the low quality LEDs used and driven by PWM instead of the normal constant current mode.
- The acrylic casing for the front is distorted after prolong exposure to sunlight (and the associated heat).
- Rectification is still in the making. Better quality LEDs have been acquired. Will use constant current mode instead of PWM and will be making PCB for the LEDs. The prototype LEDs were hardwired.
- The challenge now is to find suitable casing... milling solid aluminum for the casing is just too tedious and costly...
Other than the above, I've been generally lazy for the past weeks... I'm not sure if it's the new workplace, the growing daughter or something else... nonetheless, I'll be working on something soon... just to get myself back on the active mood...

Finally completed... the blink blink project...

2008-07-28T08:30:00.005+08:00

Minor Update: 31/07/08
The unit were used as planned. Unfortunately the tack soldering on some of the LEDs gave way (probably due to vibration) resulting in some of the LEDs not lighting up...:-( Not major issue... will make proper PCB for it next time... may revise the size too... also there's some glitch on the software that need to be fixed... simple fix already done... thanks to 9w2alt for testing the unit and for the design input...

Hello again all,

Sorry for the very long silence... very much tied up with work and taking care of my little princess who is too active for my age... hi hi...

After the long and treacherous journey, the project is finally completed... 9W2ALT took delivery last night and will be fixing it to his vehicle today... hoping all goes well for the live use on 30th June...

Photo below show the completed unit comprising the interface module, the power control module and the LED banks. The LED banks are to be mounted using the suction cup base as in the photo...

Close up photo of the LED banks... don't you love CNC... ha ha ha... too bad I can only do max of 8"... will disturb Yau or Dexter for longer units...

Close up photo of the interface module and power controller box... will definitely change the interface design in the future... once cased, it is too big... will probably use handphone LCD for next design and use a smaller switch or joystick type...

Here's a short video of the LED in action... sorry for the quality... using my digicam as a videocam...

LED Flasher... in development...

2008-06-13T12:26:00.002+08:00

I've been busy for last one month... shifting work place and all... not much time left for hobby... :-(

Anyhow, I've started working on an LED Flasher for a friend... just completed the interface box PCB and will start coding soon... the completed unit will consist of 3 separate module...

The interface module... for the driver to select the various blink modes for the LED...
The controller module... the actual unit controlling the LED banks...
The LED modules... two for the rear and one for the front...

More on this later... here the photo of the interface module PCB... mocked up... yet to be completed...

Asus EeePC... Warranty voided...

2008-05-13T09:02:00.005+08:00

Update 080514:
Photo below shows my mods. The 8GB SanDisk Cruzer 8GB drive is on the lower right. The wires going to top right is for the bluetooth module. The bluetooth module is placed on the left side of the LCD unit. Few hours of troubleshooting leads me to believe that the USB points on the spare ePCI slot CANNOT be used for bluetooth... no logical explanation... my module just not detected... if I put a thumb drive there, it worked fine so it's not a wiring issue... I end up swapping the spare USB connections... the one on the spare ePCI is used for the thumbdrive and the USB near the WiFi card is used for bluetooth... problem solved... :-)

For those installing WindowsXP onto the EeePC, this link outlines step-by-step process for smallest footprint using nLite freeware.

Original post:
I just couldn't stand not having bluetooth built into the EeePC so... the internet saved the day again... after going through several sites on how to mods the EeePC, I took the plunge as well... While at it, I added additional 8GB of USB drive inside the unit too... As for the USB drive, I used SanDisk Cruzer Micro 8GB... A quick speed check shows that the Cruzer is almost as fast as the built in SDD... only about 15% slower... Should be able to run apps from the USB drive as well... I will be adding my photos of the mods later but for those keen on doing the mods, here's a good reference site... Asus EeePC References

Asus EEE PC... my new toy...

2008-05-07T09:09:00.004+08:00

I've been lugging the Sony Vaio TR3 notebook for the past 4 years. It has served me well and I have nothing much to complaint except that the webcam failed after 1 year. I don't use it anyway so I didn't bother to get it fixed.

My friend 9W2AFY brought the subject of Asus Eee PC for special uses... After doing some study and looked at the unit, I fell in love and bought it last weekend. It was loaded with Xantros Linux and have about 40 applications built-in. Since I have been a Windows user for along time, my familiarity and gadgets are all windows-based. I reinstalled the system with Windows XP Professional the same night... It worked with no problems and surprisingly fast for a Celeron 600MHz system.

Spend the last few days installing other applications including Microsoft Office, MapKing, some utilities and some of my must have applications for my hobby (MikroC, PicKit2, etc). My first thought is that the 4G SDD (Silicon Disk Drive) is kinda small but when you consider the applications you intend to load on it, I still have more than 1G of free space... The small screen limits the type of application you can run (screen is 7", 800 x 480 display).

Pictured below is my Eee PC next to my trusted Sony Vaio TR3 and behind it is a 19" LCD monitor... It's tiny, less than 1kg in weight... no moving parts... decent battery life...

Some link on Eee PC for those who wants to take the plunge...
Asus EeePC Website.
Eee PC News, Mods and Hacks.
or just google "EEE PC Mods Hacks" if you're into mods and hacks (like me)...

For those fellows out there who think I'm crazy... check out this link... and you'll realise that I'm much better that some others out there... :-)

A2ZCNC Monster (mini)Mill...

2008-05-02T12:25:00.003+08:00

They started out as making upgrades for the Sherline mill... giving extra travel... ballscrews... riser blocks... etc

Now, if you were to put all the possible upgrades together, the only original parts remaining are the stepper motor mounts and the spindle assembly... I guess very soon that will go away too...

And here's the 1 million dollar question... who's gonna sponsor the upgrade for me... :-)

The A2ZCNC 'monster' mill...

Here how the tame little Sherline creature looks like before the metamorphosis...

9M2DS 77th Birthday Gathering...

2008-05-02T10:21:00.006+08:00

In honor of his iconic role to the amateur radio community in Malaysia, the local gang in Klang Valley area held a small yet cheerful birthday gathering for 9M2DS, passionately called Pak Dollah, on his 77th birthday. We all wish him a great live for the years to come...

Some photo from the event below:

My new base system setup...

2008-04-24T08:52:00.003+08:00

Finally got the courage to put up my base antenna and home base rig. It's scary doing it during this rainy and thunderstorm heavy period... Just hoping for the best, that the photographer in heaven won't be taking any aerial photo, with a large flash, of my setup any time soon (or later)...

Thank you to a dear friend, the antenna went up and the cable was dragged into my project room. So far the setup has been working well. The setup consist of:

A Diamond X300 Antenna: Dual Band (2m@6.5dB & 70cm@9.0dB), double stack 5/8
20m of Diamond Supergainer Series RG8 cable
An ICOM IC-2200H Mobile Tranceiver: Single Band, VHF, 65W max TX
A MeanWell 12V@12.5A switching power supply.

Antenna mounted direct to the wall with the provided bracket. Did the installation on Sunday when the hardware shops are closed thus no fancy bracket could be bought...

The antenna as viewed from the front of the house... so far no complaint from the neighbors regarding any interference... may be because most are on satellite TV already...

New option for Bluetooth on Amateur Radio Rig

2008-04-16T17:07:00.006+08:00

Further to this blog "Alternative Bluetooth for Amateur Radio", I came across the following device on ebay. Perform the same function and much cheaper... really tempted to get it to try... anyone keen to join... would save some shipping if buying multiple units...

To see what other hams are doing with the unit, just google for "JABRA A210 Amateur Radio"

This video is highlighted by peihong... for those keen on doing this...

Double Sided PCB Milling

2008-04-03T15:51:00.001+08:00

For those with CNC, here's a motivational video to show what you can do...
Video credit goes to MillPCB

DIY GSM Yagi Antenna

2008-04-01T14:12:00.002+08:00

This is another case of too many hobby but too little time...
3G reception at my house is intermittent at best so I decided to consider putting up external antenna for my mobile phone... As usual, I search the net and the following site (click the image) seems to provide most information I need... Now awaiting the cable adapter for my Sony Ericsson phone to arrive from the US...

Reference on Various Sound Pickup Circuits

2008-03-27T15:36:00.005+08:00

Since my venture into the 'remote' mic for the mobile rig, I've been searching for more ways to improve the sound quality. Came across the following website which prove useful as reference.

Sound Pickup and Relevant Schematics

APRS Information / Kits

2008-03-26T13:17:00.005+08:00

The amateur radio in Kuala Lumpur recently held a knowledge sharing session regarding APRS (?)... Unfortunately I was unable to attend due to personal commitment... It is a subject of interest to me so I search the net further for more information... then, being an electronics maniac, I started thinking what to make or buy :-)

Came across the following website providing various products with full schematic, firmware, pcb layout and the rest... a commendable effort by the owner of the site, Dinesh Gajjar. Clicking the image will take you to his APRS section... go check it out...

Update to microphone circuit...

2008-03-24T12:38:00.009+08:00

After less than ideal performance using the unit below (hissing on high gain, whining from engine noise, hollow sound, etc), I did some more digging on the net to look for possible fix... I find this article/document to be very informative and deserve a mention here on my blog for others to checkout...

I'll be changing my opamp tonight with one that has very low 'input bias current'... I have a few LMC6081 on hand and I'll use those... the opamp I use now is CLC449 (obsolete) with about 50uA input bias current... the LMC 6081 is spec'd for 100pA! Orders of magnitude lower than the CLC449...

I'll add the output and grounding resistors as suggested by 9W2DTR... I'll set the output resistor to 100R and the ground resistor to 100k... I'll add some ferrite beads on the power lines as well to tackle the engine noice...

I will update on the performance later... stay tuned... :-)

Update: March 25, 2008
The fixes above worked... audio is cleaner, clearer, louder with no whining...

Remote MIC and PTT switch for Mobile Rig

2008-03-21T08:38:00.006+08:00

I have always wondered why there is no 'hands-free' kit for ham mobile rig... For the handy/portable, you would have the whole range from normal PTT to throat mic to bluetooth unit...

Typical for any mobile rig, you would need to bring the mic to your mouth and press the PTT to talk... I'm not sure what the law actually state, but I assume it's illegal to do this, since talking on the mobile phone without a hands-free kit is illegal here...

So I came up with 'look-like-hands-free' for our mobile rig... It's basically a simple opamp-based electret mic pre-amplifier with very minimal gain and the switch for PTT... The red button is the PTT button and a spare connection is provided near the RJ45 jack for additional trigger... The mic is a normal tie-clip electret mic... The wiring are done for my Kenwood TM-V708 mobile rig but it can be fitted to almost any rig... just need to identify the correct wiring to use...

So, with this unit, I would clip the microphone to my shirt or collar and the box will be somewhere near my center console... pressing the button will not be obvious anymore because it's no longer done within normal field of view... Here's the photo of my 'looks-like-hands-free' mic and PTT for the mobile rig.... :-)

Get the Schematic & PCB Files

New Blog Created for PIC Lessons

2008-03-19T11:49:00.004+08:00

Update: CNAME has been updated. The blog can be accessed using pic.9w2bsr.com

As some of you already know from here, few of the regular gangs will be starting our PIC exploration soon... To facilitate that and to avoid clutter to this blog, I've setup another blog for that purpose... for the moment the site is very bare but expect it to be very active very soon... the link is here... very long until my CNAME is updated...

Deciphering Battery Voltage

2008-03-17T08:50:00.007+08:00

9W2RYZ gave me the following chart which prove useful to those trying to decipher the car battery voltage... BTW, I have coded a new firmware for the battery monitor to do the followings:

The display will alternate between various readings:
-C- realtime voltage; -L- lowest voltage; -H- highest voltage; -T- trend.

For trend, ^t_ indicates declining voltage; -t- indicates constant voltage (<0.2v); onblur="try {parent.deselectBloggerImageGracefully();} catch(e) {}" href="http://4.bp.blogspot.com/_tMtO23Q5vm4/R93ZJINI8qI/AAAAAAAAATs/DG0vpe0CDv4/s1600-h/Battery-Chart.gif">

Alternative Bluetooth for Amateur Radio

2008-03-13T17:11:00.003+08:00

Upon future exploration into the Bluetooth foray, I came across this module on Amazon that might fit the bill for most Amateur Radio bluetooth conversion. It basically connects to your rig speaker and microphone jacks. After the normal pairing, QSO can then be done on a bluetooth headset. The only drawback is that it doesn't have option for triggering your PTT, thus limiting your QSO to VoX basis only...

Teaser for 9W2ALT and 9W2LYZ...

2008-03-13T08:54:00.007+08:00

Here is the startup display of your voltmeters...
They just underwent 7 hours of burn-in test last night...
No problem...
On the topic of battery monitoring, note below is extracted from Wikipedia...

These are general voltage ranges for six-cell lead-acid batteries:

Open-circuit (quiescent) at full charge: 12.6 V to 12.8 V (2.10-2.13V per cell)
Open-circuit at full discharge: 11.8 V to 12.0 V
Loaded at full discharge: 10.5 V.
Continuous-preservation (float) charging: 13.8 V for gelled electrolyte; 13.5 V for AGM (absorbed glass mat) and 13.4 V for flooded

All voltages are at 20 °C, and must be adjusted -0.022V/°C for temperature changes.
Float voltage recommendations vary, according to the manufacturer's recommendation.
Precise (±0.05 V) float voltage is critical to longevity; too low (sulfation) is almost as bad as too high (corrosion and electrolyte loss)

Typical (daily) charging: 14.2 V to 14.5 V (depending on manufacturer's recommendation)
Equalization charging (for flooded lead acids): 15 V for no more than 2 hours. Battery temperature must be monitored.
Gassing threshold: 14.4 V
After full charge the terminal voltage will drop quickly to 13.2 V and then slowly to 12.6 V.

For more information, click here

Sorento Fuel Consumption Chart

2008-03-12T13:34:00.006+08:00

To my Sorento gang, here my fuel consumption chart for the past 65,000km... Long term average is 9.00km/l... Almost 100% using Shell Diesel... Refueling primarily in Taman Desa, KL with occasional outstation refueling... click image for larger picture...

Laser-based referencing...

2008-03-10T10:50:00.007+08:00

I received the laser modules I ordered from DealExtreme last week... Of the lot, I ordered a few that output cross-beam... These were meant to be used on my Sherline as a referencing tools (sorry 9W2GU, another cnc enhancement).

Here's how it was modified... Take the module apart but don't remove the laser from the center piece... Enlarge the original hole at the back (where the wires were) to fit suitable shaft... I used 6mm countersunk screw so I enlarge the hole to match... fix the shaft to the back case... then drill new hole on the side (diameter 3mm or larger) for new exit point for the wires... carefully reassemble... chuck it in your spindle, lower it to your preferred height and focus the lens for a finest line...

For alignment, drill a small hole on any workpiece... then without changing x-y, chuck the laser module in... adjust/tilt the focusing lense so that the lines cross exactly on the drilled hole... Loctite the lense, let it set and you're done...

The modified module...

The result on the Sherline... I was able to focus the lines to about 0.25mm in width... pretty good for a USD4 module and 15 minutes hack...

Simple 2 input NAND circuit

2008-03-06T13:08:00.005+08:00

Someone asked me to troubleshoot a problem... not sure what the circuit looked like... this is one possible way to do it... question or discussion via the chatbox or comments, please...

More explanation can be found here...
BTW, I'm no electronic expert... just a tinkerer who has burnt my fair share of chips, transistors, fuses, and so on... :-)

Battery Monitor Unit - Updated

2008-03-06T08:56:00.006+08:00

The update on the automotive battery monitor project... Design, prototype and coding done... The unit will flash the display if voltage drops below 11.0V or exceeds 15.0V... like everything else, the limits are programmable (not by end-user, advise when ordering)...

I'll offer two options... cased and tested PCB... the casing I'll use will be basic... for nicer casing or direct mounting to dashboard, get the uncased version...
Next photo shows the indicator mounted in the intended casing... ignore the side hole... it was there from a previous project... I didn't have the opportunity to buy new casing... For those who do not like to see the white characters, we can apply the red filter in-front so the character only visible when lit up... BTW, the paper clip used to tilt the unit is not included... :-)

Amateur Radio Rig to Mobile Phone Bluetooth Earpiece

2008-03-03T17:26:00.003+08:00

I had the idea of linking a normal mobile phone bluetooth earpiece to an amateur radio tranceiver using a homebrew bluetooth 'enabling' box. After toying with idea for a while, it daunt upon me that the final price for such box would be about USD150... may not be off interest to many of my gangs...

Well, for those interested on the unit still, there's good news and bad news... the good news is that the box is ready for sale... by someone else... checkout the TalkSafe product range from this site. The bad news is that the price is not attractive enough for me... will explore other options still...

The pendant is finally done... yahooooo

2008-02-29T08:53:00.006+08:00

Finally complete the pendant as it was originally planned. All toooo happy with the outcome. The front label was printed on regular paper using a color laser printer. It was later laminated (top side only) using a lamination machine. The LED holes were punched using the cheap single hole paper puncher... just perfect for the LED holes... The button holes were cut using a circle cutter... the cutter had a minimum hole size of 10mm... slightly bigger than the button but, in the end, it gave a better look to the unit... 3M adhesive spray hold everything flat and permanent... the sides and bottom are covered with black velvet (left over from previous project)... it gave a matte finish and provide good feel when you're holding the pendant...

It is during this kind of moment, I pat myself for being tools collector... I have very strong tendency to buy tools even though I might use it once a year! The hole puncher, the circle cutter and the laminating machine make the whole process very enjoyable...

%^$#%%^$%:-(*:-(*... just realized that the X-Axis LED is wrongly labeled as Z-Axis... arrggghhh... dang....
I'm just gonna leave it as it is... I designed the unit, I know where X-axis led is anyway....

New casing for the pendant

2008-02-28T09:02:00.007+08:00

Here's what got done last night... I milled the bottom half from a solid plastic piece (not sure what type of plastic it is) and then milled the top cover plate. Having a CNC mill make the whole process effortless... Decided not to engrave the legend for the buttons as this is a test unit anyway... will probably paste a full size label later on once I decided what the buttons should do...
Should have use a taller switches, it will give enough 'headroom' to enclose the PIC inside the casing... Nonetheless, it is a beauty in disguise, having the 'open' cover for the PIC will allow me to take it out for reprogramming if I need to fine tune the pendant as the two halves of the casing is permanently glued...
My current thinking on the label and buttons functional mapping...Link to CNCZone thread on this pendant is here... Some more details and discussion there...

Update on Pendant Build...

2008-02-27T09:08:00.004+08:00

27th February Update:
Finished coding the controller and fine tuning last night. Wired it up to the parallel port and it worked well. The indicators are in sync with Mach3 settings (for selected axis and MPG modes). Now, I don't have to look at the screen to know which axis is selected (X, Y, Z) or what MPG mode I'm using (X1, X10, X100, continuous)... a real time saver...

Will be working on the casing tonight...

Mach3 Pendant... Work in Progress

2008-02-26T14:57:00.007+08:00

Just a quick update on the progress of the new pendant for Mach3 that I am working on. The PCB has been completed and populated as shown on the right. The empty socket is meant to hold the PIC microcontroller to manage the quadrature signals to the parallel port. This pendant requires a total of 13 input/output so a second parallel port will be totally used up.

I am currently coding the microcontroller codes and it should be completed before this week ends. After full functional test, I'll decide on suitable casing for the unit... probably another acrylic based enclosure...

4 buttons are reserved for Axis+, Axis-, AxisSelect and JogMode... The rest of the other buttons can be mapped to other functions in Mach3...

New Casing for Webcam & New Clamp

2008-02-22T08:36:00.004+08:00

After initial trial with the webcam for visual workpiece positioning and referencing, I decided to make more robust casing for the webcam. Made out of aluminum with a steel 6mm shaft, the casing is very rigid and robust. Unfortunately, as a result of perfect workmanship, the shortfall of the webcam became evident... It turns out that the sensor on the camera is not perfectly centered along the lense. After assembly, there is a fixed offset of 1mm on x-axis and 0.5mm on y-axis... I could just enter the offset in Mach3 but being the lazy person I am, I wanted the camera to center exactly on target... After tilting the front cover slightly, the camera is now tracking as it is supposed to...

I also make additional clamp for the Sherline. Fabricated by a machine shop, the clamp is made from steel thus it is very rigid (compared to the Sherline clamp which is aluminum). All too happy here both with the functionality and quality of workmanship.
The webcam and clamp side-by-side with the Sherline clamp shown for reference. What a beautiful picture... (for those who know how to appreciate it...)

Amateur Radio Foxhunting Revisited...

2008-02-20T09:24:00.005+08:00

After a long silence about this topic, some brave souls would like to restart this activity. I'm glad to be of help... below are some of the links I've gathered before relating to foxhunting... Photos courtesy and credit to the originating sites...

International Amateur Radio Union Region 3 Site detailing various rules and guidelines for Foxhunt competition...

750mW Homebrew Fox

Yagi Using Measuring Tape
Another Site on Measuring Tape Yagi

Attenuator for the Hunting A Whole Bunch of Information Here
An My Own Fox

PIC-Based PLC for Machine Monitoring...

2008-02-20T09:10:00.003+08:00

After months of working of hobby that spend money, I needed a way to get involved in hobby that generate money... After short discussion with 9W2DTR, I quickly design and built the following circuit in hope it will generate some money for my hobby spending... It's basically a simple analog voltage monitoring device... It compare 2 different analog inputs against 2 different setpoints and triggers the output accordingly... The LCD, button and a simple potentiometer is there to allow for setpoint setting and input monitoring. It's already functional, just waiting for delivery of the suitable chip for the controller from RS Electronics... While the PIC16F716 has a lot of features, it is lacking EEPROM data storage... needed for setpoint storage... Overall board size is 4.0" x 4.5"...

Webcam on Sherline and Mach3

2008-02-14T08:20:00.004+08:00

I received the webcam I ordered yesterday afternoon.

After removal of a few screws and a quick cut with a cutter, the NEW webcam was butchered to what remains as shown in photo below...

The same webcam on the Sherline for size comparison...

Mounted on the chuck... The shank of the webcam pillar is 5mm...

A close up photo of the webcam mounted on the high speed spindle... After a quick alignment, a drop of superglue fixes the plastic ball to the webcam casing...

A screen capture showing the video using Mach3 video overlay... I didn't do a screen capture of the CenterCam image which was better and had more options...

Overall, I'm very happy with the webcam... picture quality is very good, exposure adjustment is perfect even in minimal lighting condition... Possibly want to make better housing for the webcam to ensure perfect alignment everytime it is used... or abuse...

In the pipeline...

2008-02-11T14:01:00.000+08:00

I've been busy thinking what to do next... As those who knows me, I enjoy designing and making things but not necessarily use them... I just enjoy learning...

Here's what to expect in the next few weeks...

I just came across this site on using webcam for workpiece referencing and planning to use it for my Sherline. After looking at ways and means to stick home switches to Sherline, I figure this is an easier alternative. Found webcam below at the local auction site and it seems a perfect fit... Ordered mine and I will update later on results...

I also got hold of a bunch of new PIC16F716 from Farnel recently. Buying them in bulk (25pcs) result in per unit price of slightly above RM4... cheaper than Pasar Road PIC16F84! So from now on, most of my PIC-based project will be based on this chip... The chip has 2k, 4 8bit ADC, 4 CCP/PWM, 2 8bit timers and 1 16 bit timer. The first project will be a Mach3 pendant (yes... another one... no encoder required... no driver required... just a lot of switches...)