Both the robot and the base station had a lot of code that was
identical, like data structs, constants, radio library etc. The chosen
solution was to extract all shared code into a static library and link
the station and robot against it.
Transmit 'true' from robot to base station if robot sonar distance is
below a set threshold and then turn on ('true' received) or off ('false' received)
base station's signal LED.