Chief Delphi - Does anyone know what sensors we can use?

Ultrasonic and IR sensors are perfectly legal.

In general, most types of sensors are legal so long as they do not interfere with other drivers or other robots, do not harm people, robots, or the field, and do not violate any other rules regarding the control system, power distribution, etc.

From "The Robot" section of the manual-

Quote:

The FRC robot control system has been designed to provide advanced capabilities for the ROBOTS. The system has been designed around an open architecture that will allow teams to easily develop custom software to control the ROBOT and add electronics and custom circuits to expand the functionality of the ROBOT. Custom circuits may be used to indirectly affect the robot outputs by providing enhanced sensor feedback to the cRIO-FRC to allow it to more effectively control the ROBOT.

and

Quote:

<R68> All outputs from sensors, custom circuits and additional electronics shall connect to only
A. other custom circuits, or the following:
B. additional COTS electronics, or
C. input ports on the Digital Sidecar, or
D. input ports on the Analog Breakout, or
E. the RS-232 DB-9 serial port on the cRIO-FRC, or
F. the Ethernet bus connected to Port 2 of the cRIO-FRC, or
G. the CAN-bus if and only if all Jaguar speed controllers on the CAN-bus are wired in full compliance with Rule <R63> and Rule <R64>, or
H. the sensor inputs on the Jaguar speed controller.