Abstract: Inflation pressure of an inflated article, e.g. a wheel tire 12, is measured by pressure sensing apparatus 10 located on the inflated article. Portable apparatus 20 is brought into proximity with the sensing apparatus 10 and a power signal is transmitted for the portable apparatus to energise the sensing apparatus. The portable apparatus acquires pressure data signals output by the sensing apparatus, processes these data signals and displays an inflation pressure value. The power signal and pressure data signals are transmitted by engaging a probe 24 provided as part of the portable apparatus with a cylindrical body member 13 of the sensing apparatus. A particular advantage of the portable apparatus is in acquiring and displaying inflation pressure values of aircraft undercarriage wheel tires because the aircraft power does not have to be switched on and the cockpit entered to obtain inflation pressure readings.

Abstract: Vehicle wheel tire inflation pressure, e.g. an aircraft undercarriage wheel tire, is measured in real time by a sensor assembly mounted on a rotary part of the wheel. The assembly includes a piezoresistive cell exposed to inflation gas pressure and an electronics module comprising an assembly of three printed circuit boards (PCB). A power signal transmitted from the vehicle to the electronics module via a rotary transformer is conditioned by PCB to provide an energising signal for the cell. Pressure and temperature signals output by the cell are received by the PCB and converted to digital form before being applied to address locations in a look-up table of PCB which holds pre-calibrated cell outputs. Data from the look-up table is processed to obtain a corrected real time pressure value which is transmitted to the vehicle. If desired, a temperature value may also be transmitted.