Self-powered tire monitoring system

In a vehicle including a frame and a component mounted to the frame, a component monitoring system comprising:

• an energy providing system affanged to generate energy upon rotation of the tire;
• a sensor system coupled to said energy providing system to be provided with energy by said energy providing system, said sensor system obtaining data about a first property of the component and converting the data into signals;
• and
• a communication system arranged on the frame and wirelessly communicating with said sensor system to receive the signals from said sensor system and derive from the signals the data obtained by said sensor system, whereby a reactive system on the frame of the vehicle is responsive to the data obtained by said sensor system,
• said sensor system including a SAW device reactive to changes in the first property of the component, first and second oscillators coupled to said SAW device and whose resonance is determined by said SAW device such that an oscillation frequency of said first oscillator varies with the first property and an oscillation frequency of said second oscillator does not vary with the first property, and circuitry to process the oscillation frequencies of said first and second oscillators to transmit signals at a frequency dependent only on the first property to be received by said communication system and which enable said communication system to derive the first property of the component.