# Tachometers (Revolution Counters)
Tachometers (also known as revolution-counter sensors (opens new window)) can be used to measure the rate of rotation turning vehicle parts like rotors, engines, or wheels.
Currently PX4 just logs RPM data: it is not used for state estimation or control.
This section lists the tachometer sensors supported by PX4 (linked to more detailed documentation). More detailed setup and configuration information is provided in the topics linked below (and sidebar).