Abstract: A wireless data display system has a receiver/display unit tuned to the same frequency as a sensor/transmitter unit for monitoring wheel rotation for a vehicle such as a bicycle. The two units are preferably battery powered, and their circuits are designed for low power consumption. Both units have directed antennas positioned in alignment with each other. The receiver includes a tunable antenna to enhance signal reception and reduce sensitivity to a transmitter of an adjacent system, as well as filter and latch circuitry to reduce interference from EMI or RFI or from adjacent operation of a similar transmitter/receiver pair.

Abstract: A device which monitors the characteristics of an image cast upon a radiation sensitive substrate. This includes a shadow casting object or mask and at least one source of radiation disposed above the object or mask so that the image cast on the substrate can be analyzed.