Why bother? How much charge is in the battery. So we can keep the cars going for as long as possible and as fast as possible. To out find the aerodynamic and rolling friction. Display speed. To find out motor temp.
Primary functions Display current speed Display average speed Display motor current Show current battery charge Show how battery charge is going for this stage in the race ie show if the batteries are draining to quickly or have more chargethan is needed for the race.
Possible other functions Control motor speed if motor speed controller is present. This could automatically set the motor speed based on the charge present in the batteries and the race duration. If motor speed is controlled could have a boost facility for overtaking Telemetry of information back to pit crew through radio link. A Laptop computer could be used in the pit for this. Possibly use 27MHz radio control frequencies ? Telemetry could be bi-directional
Work to be done Work out basic design Design Circuit and PCB (adult ?) Make PCB's (the boys) Build the PCB's (the boys) Make a simple test bed: sheet of wood with sensors and a small motor for testing (the boys) Program the computer (adults + boys)