Introduction: Crazy Mouse

About: I'm a mechanical engineer, and I like computer programming, mechanics, electronics and specially the robotics.

Crazy Mouse is a computer mouse that runs away when you are going to catch it!

Making this mouse is very easy: a light sensor detects the shadow of hand on the mouse and activates a timer that turns on a motor for about a second and the motor makes mouse running.
If you want to make your own mouse read the rest of this instructable.

Step 1: Things You Need

To make the circuit board you need the followings:
  -Copper Boards
  -Printed Circuit (Find files on next step)
  -22k Resistor
  -47uF Electrolyte Capacitor
  -TIP122 Transistor
  -555 IC
  -10k Potentiometer
  -Some Wire
  -Soldering Iron
  -Soldering Wire
  -Circuit Boards Acid
  -Paper Tape
  -Wire Cutter
  -1mm Drill

To make the mouse you need the followings:
  -Old Computer Mouse
  -Small Motor
  -4 AA Batteries
  -A piece of Rubber Tube
  -1N4148 Diode
  -0.1uF Ceramic Capacitor (104)
  -Soldering Iron
  -Soldering Wire
  -Some Wire
  -Some Tools

Step 2: The Circuit

Download the circuit PDF file and print it on an A6 glossy paper with a laser printer.
R1 = 22k Resistor
POT = 10k Potentiometer
C1 = 47uF Capacitor
J  = Jumper = A piece of Wire
U1 = 555 IC
Q1 = TIP122 Transistor
PHTCLL = Photocell
MOTOR = Small Motor
BAT = 3-6V Power Supply

Step 3: Making Circuit Board

1. Clear the copper side of the board from oxides with sandpaper.
2. Put the both sides of printed circuit on the board and fix them with paper tape.
3. Put the board between some pieces of paper and press the hot iron (without steam) on it for a while. (BE CAREFUL: The hot iron may lead to firing of papers)
4. Remove the printed circuit of the board.
5. Soak board in a bowl of circuit board acid and wait till all the visible copper disappears. (BE CAREFUL: You are working with acid)
6. Wash the board and clear it with sandpaper.
7. Make holes with 1mm drill.

Step 4: Soldering Circuit Parts

Place all of the circuit components on their positions and solder them.
Notice the correct direction of the IC, transistor and capacitor.
Solder two wires for power supply, two wires for the motor, two wires for the potentiometer and two wires for the photocell and solder the photocell on the small board.

Step 5: Making Mouse Case Ready

Open the mouse cover and remove its useless components and parts. (There are some SPDT switches and some shaft encoders in the mouse you can use them in other projects!)
Make a place for motor and potentiometer with your tools.
Drill a small hole on the back of the mouse to place the photocell behind it.

Step 6: Placing the Motor

Put the rubber tube on the motor shaft and attach the motor inside the mouse with some glue.
The motor must be able to rotate the mouse ball.

Step 7: Placing the Potentiometer

Attach the potentiometer to the mouse wheel and fix its position with some glue.

Step 8: Soldering Motor Components

Find the motor poles that make the mouse move forward with two wires and batteries.
Solder the 1N4148 diode reverse to the motor connectors. (Back EMF protection)
Solder the 100nF ceramic capacitor to the motor connectors. (Noise protection)
Do not solder these components on the board or somewhere far from the motor, solder them right on the motor.
Solder the motor wires coming from the circuit to the motor.

Step 9: Attaching Photocell

Attach the photocell right behind the hole you made on the mouse back with glue.

Step 10: Power Supply

Solder two of mouse wires to the circuit power supply wires.
Cut the connector at the other end of the mouse wire and solder the wires to a battery holder.
You can use the power coming through the mouse wire from the computer main board instead of cutting mouse connector and using 4 batteries but it is not recommended because it may cause damages to your main board.

Step 11: Ready to Action

1. Close the mouse cover.
2. Hide the batteries behind the computer.
3. Rotate the mouse wheel till the motor turns off.
4. Gently rotate back the mouse wheel till the motor turns on.
5. Rotate the mouse wheel a little in reverse direction and wait about a second, continue this till the motor turns off.
6. Put the mouse ball under the mouse.

Step 12: Optimization

If you want the mouse to run more use a higher value electrolyte capacitor.
If you want the mouse to work in darker areas use a higher value potentiometer.
And if you use a gearbox after motor and connect it to a wheel instead of mouse ball, certainly you will get better result.

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