For Richard Hopkins and Jen Harmel's complete instructions on how to build your own penny slot machine, microcontroller code, and a video of the slot machine in action, click here. To view the parts list, click here.
Gamblers who play engineering students Richard and Jen's handy desktop slot machine simply insert a coin and press a button or pull a handle. Three stepper motor microcontrollers generate a random number between 0 and 7, using this number to spin the three reels to new positions. For a cool visual effect, the reels are spun through multiple rotations. If the reels arrive at a winning combination, "winner" is displayed on an LCD, chimes ring, and a central microcontroller sends pulses to a relay that runs a set of solenoids that push out the winning coins. Viva Las Vegas!
Desktop Slot Machine Parts List
Allied Part #
Parallel 16×2 LCD Display
Bipolar stepper motor driver
1 kV resistor
10 kV resistor
4.7 kV resistor
22 pF capacitor
0.1 µF capacitor
22 kV ceramic photocell
5V dc relay
4 MHz crystal oscillator
NPN power transistor
Additional parts required: 5 PIC 16F84A microcontrollers; 1 bright white LED; 3 bipolar stepper motors; 3 H-bridge with flyback diodes; 1 computer power supply; 1 slot machine N.O. spin button; 1 digital sound module; 1 amplified computer speakers; 1 car emergency brake handle; 1 doorbell
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