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Author Topic: Reverse engineering coin comparator (grey optic)  (Read 611 times)

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Offline somehobo606

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Reverse engineering coin comparator (grey optic)
« on: July 12, 2016, 03:41:19 PM »
I bought a Universal video poker machine but it didn't have a motherboard in it. It seemed to have everything else so I figured I'd just connect all the peripherals to a PC and run poker software. Been a fun project so far but requires me to reverse engineer everything.

Anyone know how the coin comparators work? It's the grey U shaped ones and says "U-87P". It has three wires coming off, I assume one is power, one ground, and one signal. I'm not sure if the power would be 5V, 3.3V, or something weird. I assume the signal is 0V with no coin passing through and matches power voltage when a coin is there.

It's got a high speed hopper in there with 8 wires coming out which I think I lack the patience to reverse engineer :P but if anyone has an owner's manual for the machine I'd love a copy!

Offline UNIMAN

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Re: Reverse engineering coin comparator (grey optic)
« Reply #1 on: July 12, 2016, 06:14:31 PM »
That is an ambitious project I know I wouldn't tackle!! There is no real good manual for the 8304 poker machine. But there is a good manual for the 8116 slot machine.
This manual details inputs/outputs basically same as used in poker machine.

The grey optics are a 5vdc photo-transistor/photo-diode configuration. The three wires are pink 5vdc, black ground, and the other is signal. When in idle state the optic sends a logic HI, when a coin passes through (or anything for that matter) it sends a logic LO. The two that are coupled together are used see the coins incerted. Two are used so only coins going down are counted. Coin must pass first optic and then second optic in proper timing to count, otherwise a TILT is sounded. This is for those who might try a coin on a string (Yo-Yo trick) to cheat the machine. The lower single optic is used when the hopper fills with coins, a ground bar is touched by the coins in the hopper and the mpu engages the diverter solenoid. Incerted coins are "diverted" from going into the full hopper and down to a bucket in the slot stand. This single optic tracks how many coins have been diverted. (this optic not usually used for home use and can be used as a spare)


Offline somehobo606

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Re: Reverse engineering coin comparator (grey optic)
« Reply #2 on: July 14, 2016, 10:29:41 AM »
Great info, thanks! I was wondering what that third sensor was for. I was guessing counterfeits or something.

Project is going pretty well, pretty much done actually. I'm using IGT players edge plus software and running it in MAME. I got a USB encoder and hooked up all the buttons to that. Now I have the coin input working with the sensors. I'm just using one optic, Im not too worried about people cheating (if they're going to steal something in my house they might as well steal the cash lying around in the kitchen).

Worst case I'm going to make my own coin hopper but it'd be cool to use the one in there. Seems like I'll have a lot of timing problems with a high speed hopper though :P


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