Tire pressure indicator including pressure gauges that have a self-generating power capability

A tire pressure indicator for a set of pneumatic tires of a vehicle, said tire pressure indicator comprising a plurality of pressure gauges, each of which includes:

• a casing formed with an aperture and adapted to be mounted on a respective one of the pneumatic tires such that air in the respective one of the pneumatic tires flows into said casing via said aperture;
• a signal generating device disposed in said casing and capable of transmitting wirelessly a pressure signal corresponding to pressure of the air in the respective one of the pneumatic tires;
• and
• a power supplying device disposed in said casing and connected electrically to said signal generating device so as to supply electric power for operating said signal generating device, said power supplying device including a self-generating voltage unit which has a spring plate with a mounting end secured to said casing and an opposite distal end, a weighting block secured to said distal end, and a piezoelectric unit secured to said spring plate, said spring plate being capable of deforming so as to subject said piezoelectric unit to mechanical stress when the pneumatic tire to which said casing is mounted is in motion so as to enable said piezoelectric unit to generate a voltage output.