Power consumption protocol

Low power consumption protocol A telemetry unit ( 100 ) is provided for mounting inside a pneumatic tire, which includes a piezoelectric element ( 114 ) supported in a housing ( 112 ), with an actuator ( 136 ) arranged for contact with the element ( 114 ), to deflect the element ( 114 ) in response to external forces acting on the actuator ( 136 ) during rotation of the tire. For every rotation of the tire, cyclic pulses of electrical charge are generated by the deflection of the element ( 114 ). The charge is stored and utilised under a power consumption protocol including the steps of: initiating power to a data measurement circuit for measuring data from the environment local to the unit ( 100 ); disabling power to the data measurement circuit; initiating power to a data transmission circuit; transmitting data from the measurement circuit; and disabling power to the transmission circuit. The power consumption protocol therefore minimises consumption of the generated power, during measurement and transmission of data by the unit ( 100 ).