Novomatic Roulette Wheel, rebuilt

I have recently aquired this small electronic roulette wheel. It was quite cheap, just 150EUR, came from now defunct hungarian casino. Gambling laws changed in Hungary few years ago, leaving just seven casinos countrywide (all under one owner). Now even "toy catcher" crane machines are considered gambling and illegal. It appears that people, who used to own machines a few years ago, now realize the laws won't be reversed anytime soon, so they tender to sell their stuff for cheap.

This wheel is labeled "Novomatic NH-265", I was unable to find any information about it, or how the complete machine looked like. May be it was a small (single player?) machine, as despite a good quality of woodwork, central plastic part has a very cheap look.

This wheel has 4 motors and 4 ball sensors.

Motors are:

Wheel spin
Ball Eject
Ball Lift
Wheel Open/Close

Later 2 motos are connected via H-Bridge, so they can go both ways.

Sensors are:

  Number - optical, triggered when any number hole bypasses sensors mount point.
  Zero - optical, triggered when Zero bypasses the mount point.
  Ball - proximity, triggered when a number with the ball in it is over the sensor.

These three sensors are aligned, so monitoring them we can easily tell what number is currently above the sensors mount point and if there is a ball.

The fourth, optical sensor, is mounted above ball "Home" and the ball is breaking optical path when it is there. (This sensor is not shown in the video above)

There are 4 end point switches. 2 for Wheel Open/Close mechanism and 2 for Ball Lift Up/Down. For now I'm not using them. But would connect later, or may be use motor stall current sensing.

I believe that electronics were aleady repaired/updated at least once, as main PCB has dual H-Bridge, but two motors, that would use the bridge were not connected to it, these two motors had new cabling and DB-15 (retro joystick type) connector for connection to somewhere else. Besides that the board contained only 2 transistors for driving 2 other motos and passthru circuits from main 26 pin connector to smaller 16 pin, going to main sensors board, ball "Home" sensor board and 2 motors (spin and eject).

By the way main PCB is labeled "Electro Chance SRL", they are a gaming solutions provider from Argentina. How they are tied to Novomatic, interesting?

Anyway I have decided to replace this board with my own one, which would have ATMega328p chip onboard to handle all the wheel driving and sensors reading, accept commands and provide results via serial TTL interface. Later I plan to connect it to NodeMCU board with 4M flash, which would run in WiFi AP mode and provide HTML5 based betting field via built in web server. Kind of self-contained party fun machine.

My board:

 ATMega328p - MCU
 L298N - Dual H-Bridge for "Ball Lift" and "Wheel Open" motors.
 PCF8574 - I2C I/O extender, 4 outputs to L298N, 4 inputs for the end switches.

I know, that L298N is quite outdated and there are better chips, but I had it in hand. PCF8574 could be optional, as there are enough I/Os on ATMega328 itself, it is just for experimenting.

This article is my 2nd oldest. It is 544 words long