Quote Originally Posted by KB Aluminium View Post
Hi Les,

Nice to see it all coming together nicely for you :)

Thanks Kris, I am getting there, slowly!

Charge Pump continued...

I ran a quick test this morning and the charge pump circuit worked fine through the opto-isolator. While I was testing the circuit, it occurred to me that my Estop flip flop on the IO board was no longer needed. It also occurred to me that I could use the Estop switch with the charge pump, to make a true hardware emergency stop. All I needed to do was take the NC side of the Estop switch to +5v, the NO to Gnd and the Common to Pin 5 of the 4538N. I also added a bi-color LED indicator and a 2 pin connector to take a feed over to the IO board so that Mach3 knows when the Estop occurs.

Here's the 3rd version of the circuit...

Click image for larger version.  Name: charge_pump.png  Views: 552  Size: 36.8 KB  ID: 11683

As I now have a PC PSU inside with ample 5v & 12v lines, I can also loose the 5v regulator circuit from the IO board. Hopefully this extra space will allow me to use some proper connector blocks. I simply didn't have space to fit them before, within the free version of Eagle's size limit (100mm x 80mm).