cross post - looking for circuit suggestions

[CTP]

I also posted this over on Dorkbot Blabber, but want it here too - for
help and for the record. So far my favorite suggestion for simplicity
is an optoisolator. But keep them coming, please!

Hey y'all,

I am looking at getting some of these - http://www.adafruit.com/products/786
- to make some more of my (and my colleagues') pieces coin-op. I
designed the one I was using on Awe Tomata, and while it is fine, I
have good reason to move more in the direction of this unit.

Question is as follows. This unit's output goes high for 40ms when the
right coin is inserted. The timer boards I most often use require a
switch contact to activate. Sure, I could easily put in an MCU to
solve this, but I don't wanna. (oh, and I haven't ever tested the
timer boards to see what the switch contact is doing...I have always
assumed that the closure runs to ground to start the timing cycle)(can
find the schematic for the board so can't say for sure)

Sooooo...any suggestions for analogly converting a 40ms pulse into a
contact closure?

thanks in advance
ctp

[Steven Nelson]

Most coin switches switch ground (logic low) to the I/O (Coin in line which is usually pulled high) If this acceptor produces a logic high for 40 ms then you could just tie it's output with a small resistor ah up to 1k ohm to the base of a small NPN transistor. Tie the Emitter to Ground and the Collector to the timer's input that your trying to trigger.  

ctp

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[Christopher Palmer]

Yea, that was one of the things I was going to try, I just wasn't sure (yet) if that pulse would reliably trigger the timer board was the thing.

Along the way I have resurrected an idea I had a while ago to build my own board with an MCU and a relay and eliminate the timer boards I have traditionally used. More on that sometime soonish.

thanks!

ctp