Thursday, November 15, 2007

Spindle Index Addition to Sherline/Mach3

I've been wanting to add a spindle speed sensor to my Sherline/Mach3 setup for a long time. After several failed attempt of using reflective IR optical sensor, I managed to locate and procure a hall effect sensor (from RS Electronics) to settle the matter once and for all. I had two different sensors, proportional output sensor and latch sensor. Looking for easiest way to setup the sensor, I went with the latch sensor approach.

For such setup, I only needed the sensor (Allegro UGN3177UA), a pull-up resistor (10k) and two small magnets. Three wires goes from the sensor to my driver board and PC (+5V, GND, Sensor Output). Since the sensor output is toggle using magnet polarity, the magnets are mounted to the spindle as shown below, one polarity facing up per magnet, giving a consistent 50:50 duty cycle on the output. The pocket for the magnet were milled in the acrylic using the Sherline, of course. Works on the first power up. Mounted to the Sherline using scrap acrylic, double sided tape and cable ties. Now... the DigiSpeed controller looking very tempting... hmmmm....

3 comments:

9W2DTR said...

hmmm.. very tempting.... well, still a long way to go for me... all I need to do now is to complete the whole setup before any other things..

good job there...

Anonymous said...

good one.
so where did you connected that sensor output?
to mach's index input? is it displaying the RPM correctly?

Basir Atan said...

As mentioned, the circuit worked flawlessly from first power up... It was connected to the index input in Mach3 via parallel port as you would expect...