Add additional Thrusters to arduino/i2c-slave/i2c-slave.ino

[pwoosam]

I have only implemented the elevator thruster (The one that goes up and down). We still need the left and right thrusters to be implemented so that we can send messages to them from the Pi and get them moving. Implementation of the left and right thrusters should be almost identical to my implementation of the elevator thruster.

Here are some examples of messages to the Arduino that move the elevator thruster. The left and right thrusters should be similar.

from i2c_master import Arduino

ard = Arduino()
ard.send('255', register=0x10)   # Move the elevator thruster up at full speed
ard.send('10', register=0x10)    # Move the elevator thruster up at a slow speed
ard.send('0', register=0x10)     # Turns off the elevator thruster
ard.send('-255', register=0x10)  # Move the elevator thruster down at full speed

I would like to be able to move the left and right thrusters in a similar fashion.
For example:

ard.send('255', register=0x11)   # Move the left thruster forward at full speed
ard.send('-255', register=0x12)  # Move the right thruster backward at full speed