Replacing the Pokereno Circuit Board with an Arduino

Shortly after filming the video playing the Pokereno I started losing functions on the Pokereno motherboard. I patiently waited a couple of years hoping a Pokereno would be parted out on eBay... but I had no such luck So I'm working on replacing the entire motherboard with an Arduino Mega. These are ~$20 on eBay and can be programmed to "Listen" for input and trigger output to relays.

The Mega has 65 pins so I can use the Arduino to monitor the 1) coin drop 2) the 36 card positions and then send signals to the 3) Coin-In, Winner, and Game Over lamps as well as trigger the 4) Bell and 5) Ticket Dispenser. Sounds easy right? Given the fact I'm an electronics novice, I prepared to eat an elephant.

First I mapped all the cards to the 22 Pin edge connector. Following the wire colors and verifying with a multimeter I figured out which pins on the edge connector went to the negative side of the bulb sockets.

The 36 cards are wired to the 22 pin (long) edge connector. The lamps are wired to the 14V+ lead on the transformer. When the balls drop into the deck holes the lamps are brought to ground and light up with about 10V of power and the 5 corresponding leads on the edge connector go to ground.

The edge connector is wired in 3 sets of 12. The drawing has the pin number below the corresponding card face. The squares are the backglass lamps the circles are the deck switches. As an example, I drew in one connection for pin 22.

Next up was to come up with a way to send the ~12v ground signal to the Arduino which can only handle a maximum 5V signal. The community at arduino.cc helped me come up with this. Using a couple of resistors I could create a voltage divider to reduce 14v --> 5V

Here we have a working concept, I will need 36 of these to tell the Arduino when a card lights up. After 5 are lit the Arduino will go to the scoring routine and then wait for another coin drop.

Since I'm not equipped to build a nice circuit board with 36 voltage dividers, I decided to stack up 5 optoisolators. I got the 24V --> 5V versions and they trigger just fine with the ~12v signals when the bulbs go to ground.

My buddy Jeff (Bezos) says he can send me an optoisolator for $12. I decided to use 5 of them eliminate the 36 Voltage Dividers.