Coin Acceptor – 12v to 3v

Other Miscellaneous
1

Greetings,

I’m trying to connect the[ 3-coin acceptor to a RaspberryPi. I have a 12v power supply for the acceptor and a separate 5v supply for the pi. I believe, if I read correctly, that the COIN pin pulls to ground for coin acceptance pulses, but I don’t understand if this will read as ground for my pi, or pose any danger to it, and I’d prefer to not fry it finding out. Is this signal readable (are the ground values the same) or should I have some sort of interface between them to “step-up/down” the ground to the correct signal for the pi?

Thanks](Coin Acceptor - Programmable (3 coin types) - COM-11719 - SparkFun Electronics)

2

Hello redbassett.

These are powered by 12 volts, but the output wires don’t send a voltage without some help.

The COIN and COUNTER wires on this are [open collector outputs that shunt those wires to ground when activated. What you will need to do is add a 10K pullup resistor to each wire that connects them to 3.3 volts and when they activate, they pull that to ground causing the 3.3 volts to go away. Make sure the pullup resistors connect to 3.3 volts rather than 5 or you can damage your Pi.](Open collector - Wikipedia)