Rolling ball game with steel ball on inclined plane - uses proximity sensors embedded in distributed target points, and with self-checking circuit

摘要

To allow a steel ball slowly rolling down by gravity to be unaffected in its path by mechanical sensors, proximity detectors (2) are built into each of the target areas of the game board. The detector is placed just below the surface and consists of one half ferrite (6) with coil (5) connected to an oscillator (3). The same may be a Colpitts oscillator the inductive element of which would be the coil (5) whose magnetic loading varies dependent on whether a steel ball is above the pot core or not. The emitter resistor is chosen to limit the energy level of the oscillations so that when further attenuation occurs due to currents induced in a steel ball, the oscillations break down altogether. This change can be converted into a logic level change for input to a microprocessor controlled score encoder and arithmetic circuit to add up any number of target scores. The system also comprises a self-checking circuit to ensure that all the embedded proximity sensors work reliably. The circuit consists essentially of an electronically switchable load connected to each of the pot core coils (5).