Project: Pinball

Controlling the pinball mechanics

The mechanics, that is mostly solenoids, will be controlled by the main logic computer through a microcontroller and driver electronic.

This microcontroller (MC) will also "poll" several switches and other sensors in the game.

Microcontroller board

The old board design (PB-B03) used an 80C535N microcontroller, clocked at its maximum speed of 12 MHz.

I am currently changing my design plans to use an Atmel AVR microcontroller, which will control a CAN bus to which several types of I/O modules can be connected. This solves several problems I had with the matrix design before, at the cost of more money. As this is a single hand-made hobby machine, I accept this.

Further details on that bus are yet to be defined.

Power driver circuitry

To power the coils, I plan to use two coupled transistors like BC238 driving a 2N3055.

Vcc will be +5V. There will be an opto coupler between the microcontroller board and the power driver circuitry to add an extra level of protection. The PB-B03 must not be fried.

The four or five bumpers I want to use in the game, though, will not be directly controlled by the I/O board, but directly connected to the appropriate ball sensors to make them fire, thus taking load off the main computer. The I/O board will only have the option to turn these bumpers off if the game requires this, and get notice of the bumper sensors firing through the switch matrix for scorekeeping.


Last page update: 2010-05-04