In part 1 of converting the Claw's original electronics to a Raspberry Pi I first need to analyse the existing electronics controller to plan the specifications of the new controller board and the workings of it currently.

The current machine has 3 Separate PCBs, the main controller, the "Super Card" board and the coin adaptor.

The Coin Adaptor
board is located in the front of the machine and to begin with I believed this was the main board with Dip switches, However all this board does is interface the coin mechanism to the main controller using a single wire to signal coin insertion. The Dip switches adjust how many plays are given per coin. (It's currently set to 20P per play).

The Super Card Board is located in the top of the machine, it has a selection of LEDs. One row is of 3MM LEDs which seem to just do a random pattern, the next row of 5MM LEDs are a similar row but instead are for the "Super Card Game". The LEDs blink in order from left to right of which if you land the LED on either of the 1 coin or 2 coin extra positions you win that many games for free.

The alternative is that you can land on a centre position which sets the claw to the highest strength possible and almost guarantees a win.

The Main Controller Board is located in the back of the unit and controls the whole system. It has a 8052 CPU which interfaces with multiple components including a UM3567 & 8910 for music and a API8001 for Speach.

It has primarily 7 Relays to control the motors in the machine and then GPIO to control the buttons, coin mech, super card etc.

So what do we need to replicate
The main part to replicate is the main functions which are:

  • Motor 1 - Forward Back
  • Motor 2 - Left Right
  • Motor 3 - Up Down
  • Claw Electro Magnet
  • Button Forward & Right
  • Speaker driver

So what to use to replace it?

While I could use other boards the base of it's going to be a Raspberry Pi.
I could use a Raspberry Pi 3 or Compute module. The compute module has more built in GPIO however costs more to use as you have to integrate the power circuitry.

So the alternative is the Raspberry Pi 3, Furthermore if I develop it to all use either purely the I2C or SPI Bus then I can upgrade it to future Pi models with just one connection.

So that's the plan! Next blog post will be searching through parts and coming up with a plan for the circuit board.