Thursday, December 3, 2009

My wish for this Christmas...

Monday, October 26, 2009

Parabolic Reflector for USB 3G/EDGE/Wifi

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... :-)

Thursday, October 8, 2009

Duit Raya... from Google AdSense

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...

Monday, September 28, 2009

Cheap interactive screen with WII Remote

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

Friday, September 18, 2009

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

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.

Tuesday, September 1, 2009

Naza Sorento 2.5l CRDi Fuel Consumption Chart

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

Tuesday, August 25, 2009

Bye Bye Ferric Chloride...

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.

Monday, August 3, 2009

RFM-USB Interface

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:

  1. Run the RFM12B at USB voltage (normally below 5V) which is over the design max but below the absolute max (of 6V).
  2. Replace the RFM12B with RFM12 (meant for 5V) and run the interface at USB voltage.
  3. Run the PIC at 4.2V (minimum for PIC18F2550) via voltage regulator or simple diode voltage drop.
  4. 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.

Thursday, July 30, 2009

Updated RFM12B-USB Interface

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...

Monday, July 27, 2009

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

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...

Friday, July 17, 2009

Checked your VISA statement lately...?

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...

Wednesday, July 15, 2009

Farnell Did It Again...

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

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... :-)

Friday, July 10, 2009

Creative Problem Solving

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


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

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

Thursday, July 9, 2009

Update: Cytron UIC00A Limitations

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....

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.

Wednesday, July 8, 2009

RFM Slave Testing Units

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.

Wednesday, June 24, 2009

RF Transceiver Module...

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.

Tuesday, June 23, 2009

High voltage and high current equal to...

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...


Wednesday, June 17, 2009

This is weird, but interesting!

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

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.

Tuesday, June 16, 2009

MilliOhm DVM Adapter

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... :-)

Monday, June 15, 2009

SMPS Journey continues...

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...

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.

Wednesday, June 10, 2009

Cadsoft Eagle Training/Familiarization Session

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.

Monday, June 8, 2009

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

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

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... :-)

Wednesday, June 3, 2009

Quick, Cheap, Reliable UV Exposure Box...

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...

Friday, May 29, 2009

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

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.

Tuesday, May 26, 2009

PCB UV Exposure Box DIY

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... :-)

Friday, April 24, 2009

Amateur Radio without Hand-Free

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]

Thursday, April 16, 2009

My Sorento Fuel Consumption Chart

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

Thursday, March 19, 2009

Let's save some fuel...

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.

Friday, March 6, 2009

It's been a while...

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...

Tuesday, February 24, 2009

New Digital PWM Controller for HHO Hydrogen Cell...

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... :-)

Thursday, February 19, 2009

CHEAP, effective, convenient SMD container

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.

  1. It's cheap, translucent and not pre-printed. Simpler for you to print and stick your own.
  2. 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...
  3. 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 :-(

Tuesday, February 17, 2009

CAUTION: To friends using the PIC16F88

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...

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

Tuesday, February 10, 2009

Blink Blink Revisited

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...

Tuesday, February 3, 2009

Icom OPC-478 Programming Cable

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...