[Pplug]

I need to add a charge pump to an existing machine to kill machine movements and the spindle starting when the computer is off. Ideally it would just be a passthrough board with a db25 male on one end and a female on the other that would just enable output when Mach sends its signal on pin 1 or whatever the default is.

Has anybody seen such a beast? If so, where? If I can't find one that exactly meets my needs, what are my options for charge pumps without having to purchase a new BOB?

[john-100]

I guess your looking for some thing like CNC4PC's C4

http://cnc4pc.com/Tech_Docs/C4r6_2%20USER_MANUAL.pdf

the C4 does not pass the printer port signals
what breakout board do you have , you may have an unused output you can use to with the C4 board
for instance , with a 5 axis BOB and only 4 stepper drivers you could use the unused axis step or direction signal

John

[Al_The_Man]

If you feel like winding your own and If you have the Charge pump pin on the P.C. PP. you could use a simple 555 missing pulse detector.
Use strip board and a couple of $ worth of components.
There are probably many examples as the 555 is everywhere.
Al.

[Pplug]

The CNC4PC solution isn't as plug-and-play as I would like it to be but I'm not afraid of wiring things up. I think I might just be able to use it to actuate an enable pin on the BOB I'm using.

Al, thanks for the idea but when a pre-made solution is only $30, how can you say no to it?

[Al_The_Man]

Al, thanks for the idea but when a pre-made solution is only $30, how can you say no to it?

Easy if it cost me $3.50 to make.
Al.

[Pplug]

I get $40 an hour to work and this is at least an hours worth of work to get the parts(including prototyping board), wire the board, solder it and then install and test. That's if nothing goes wrong!

I've been down this route before and it just doesn't pay in the long run. If the board cost $100, then we're talking! 😀