Updated 12/20/2011

Safety first! Wear eye protection and never touch a powered robot!

Note: Do not use Loctite or thread locks on the assembly. They are not necessary and may cause damage to the Lexan.

Note: This guide follows the assembly guide. The Sabertooth has already been installed.

Software:
  - Basic Micro Studio

Use an exacto knife to carefully pry the black tab up and slip the red wire out of the black housing as shown in Figure 3.

Bend the red wires up and use electrical tape to cover them as shown. This will prevent accidental shorts.

Schematic - Figure 5.

Schematic - Figure 5.

Now it's time to have some fun!

This program requires the Sabertooth's Switch 1 to be flipped to the "Off" or "Independent Control" position.

Upon powering up the robot, you should hear four ascending notes. Pressing A once results in a beep and slow forward motion (10%) on the left channel only. Pressing nine more times results in 100% power. Continuing to press A will make the motor act as above, except only for the right channel. The C button will control the left motor in a similar manner. Pressing the B button will reset the speed and direction of both left and right.

Note: The Sabertooth's red Error LED will light to indicate overheating or current limit. The green Status1 LED will glow dimly when power is applied, and brightly when it's receiving pulses from the microcontroller. The green Status2 LED will flash out the detected number of lithium cells when lithium mode is enabled.

Download this file (a4wd1tst1.zip) and run it. For this program, on the Bot Board II, the "B" button is throttle and the "A" and "C" buttons are steering.

Upon powering up the robot, you should hear four ascending notes.  Pressing B once results in a beep and slow forward motion (10%). Pressing nine more times results in 100% power. After the motor is at 100% power, pressing B will reduce the speed in 10% increments until it stops. Continue to press B to make the robot move as above, only in reverse.

Press Reset, then B twice. Now press C a few times to see the robot make a gradual left turn. Pressing A a few times will return to forward motion, and continuing to press A will result in gradual right turn.

Experiment with these buttons to understand how throttle and steering can be used to control the vehicle's motion.

Note: The Sabertooth's red Error LED will light to indicate overheating or current limit. The green Status1 LED will glow dimly when power is applied, and brightly when it's receiving pulses from the microcontroller. The green Status2 LED will flash out the detected number of lithium cells when lithium mode is enabled.

When you're done with this testing program, flip the Sabertooth's Switch 1 back into the "Independent Control" position!
 

The code supports three Sharp GP2D12 sensors; two in the front and one in the back.

Make sure you place the robot's right sensor on the robot's right side, facing left! Place the robot's left sensor on the robot's left side, facing right! This overlap ensures there isn't a blind spot in the center. If you switch the positions of the sensors accidentally, the robot will turn into objects, instead of away.

Attach the other GP2D12 sensor at the rear of the robot as shown. Use double-sided foam tape to hold it in place.

Schematic - Figure 11.
 

 
Schematic - Figure 11.

This program allows the robot to roam around the room without bumping into things. It uses three Sharp GP2D12 analog distance sensors to "see" things in its environment. Feel free to experiment with the variables and math in the main section of the program. The robot does a very good job navigating without getting stuck. The motor control is based on the GP2D12 sensors with a bias for forward motion. The robot will sometimes back up and turn even though there are no specific instructions to do so. Look for this and other emergent behaviors during your experimentation.