an air pressure sensor for monitoring the pneumatic reservoirs pressure. this would be incredibly useful to have
Do you actually mean a sensor, or just a gauge for a human to view?
Both would be awesome
Physical guage so judges can see you are not over filled, and a sensor so the program can react to low pressure (blink a light, display on LCD screen, stop your arm, etc)
that would be really cool 
… that would be the decider for me 2 get pneumatics