Step 6: Electronics
- the motor controller 2x25 Sabertooth http://www.dimensionengineering.com/sabertooth2x25.htm
- the arduino Uno
- and, the accelerometer.
The Accelerometer needs to be mounted preferably at axle height and vertical. The four holes on the circuit board should be facing down and the chip side to the back.
We used double sided tape as it's a good insulator and sticky!!!!!!! Make sure it's in a nice waterproof area and maybe even heat shrink it water tight. A glue coated heatshrink is good for this. We used shield cable for the wiring as it will stop any added noise getting into the system.
Make sure it is held on tight. If not you will have a bucking bull chair! Believe me I know about this!
The unit has a few switches to add.
- The dead man switch. The big red button that has to be held at all times to make the unit work.
- Main Power. Cuts power to everything. Ours was built into the battery holder.
- Joystick. Allows you to turn left/right and drive forward in up coming code.
- Tilt Adjustment. Allows you to adjust your balance point
Find a good safe, easy to use spot to mount these. Connect all units together and wire these up as per the wiring diagram.
The wiring is pretty much the same as Xenonjohn's Skateboard but without the resistors.
See our circuit diagram below.
Once it is all wired and the code has been uploaded, it's time to test. Puts ome bricks underneath it to lift the wheels off the ground. Tilt it forward and turn the main switch on. Wait your four seconds for the Acceleromoter to calibrate and hold down the deadman switch. The wheels shouldn't start yet.
Slowly tilt the unit back until the Accelerometer is vertical. The motors should start up and you should be able to slowly move it back and forward to slow and speed them up. Check the rotation to make sure that the wheels are going the right way. If not, then power the unit down and swap the polarity for that motor.
Now, you should be ready to drive the unit around.