Motion Activated Led Dice

Introduction

I’ve always wanted to build an electronic led dice, but something different from what we see on the internet. Making it motion controlled… now that’s new!   Many new cell phones that have accelerometers built in also have dice games. These dice move when shaking the cell phone. My Led Dice project will also work with a shake motion but without the use of the expensive accelerometers.

Parts List

R1                   500 ohms resistor
R2                   500 ohms resistor
R3                   500 ohms resistor
R4                   500 ohms resistor
R5                   500 ohms resistor
R6                   500 ohms resistor
R7                   500 ohms resistor
R8                   10K resistor
C1                   100nF cap
Led1 to 7        5mm flat led
Piezo               Piezo HPE-120
IC1                  16F688 microcontroller from Microchip
S1                    Normal On/Off switch
 
Others:
Box
AAA x2 battery support
PCB
Spring, screws and wire
Hex program for the microcontroller

PCB

The PCB used for this Project is single layer and its size is 31.27 mm x 42.25mm.

I’ve used x2 AAA batteries to supply 3V to this circuit making it small and light.

Download PCB files at the bottom.

The Trigger

The trigger is a mechanical device and it will sense the shaking movement. One contact will be on a spring and the other contact will be on a wire. The spring has a screw on it’s end and it will act as a weight. Placing the box on it’s side, the spring needs to have enough strength not to bend with it’s own weight. Shaking will make the spring to move and touch the wire closing the circuit and this way the microcontroller will know when it’s time to roll the dice.

Adding a small amount of polymorph will secure the spring and give a better final look.

Hex Programm

The Hex program must be saved in the microcontroller’s memory before soldering on the PCB.
The fuses OSC and MCLR fuses must be set as follow:
 
INTOSCIO                 on
MCLR                         off

Testing

Turning on the circuit, the microcontroller will initialize and light on and off all leds.
 
Shaking the box will roll the dice. The leds will simulate the rolling of the dice and the piezo will sound until the final number is displayed.
 
Once the final number is displayed it’s possible to sort another number simply by shaking the box again.

Conclusion

It’s a pretty cheap and easy to make circuit.
 
Will add more fun to any board game.

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