Smith Systems offers zero, proximity and standard digital speed sensors. All three are active sensors. The standard sensors operate at 5 to 30 kHz, the zero speed in 0 to 20 kHz, and the proximity sensors from 0 to 2 kHz. They also carry passive speed sensors to convert mechanical motion to A/C voltage without a power supply.

Sensoronix makes speed sensors including hall effect and variable reluctance types, such as analog sine wave speed sensors, with an air gap of 0.005" to 0.150", speed range of 30 to 1000 inches per second, resistance of 40 to 2000 OHM, and a ferrous material target.