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A car tach/speedometer that I designed and built for my Z28 Carmaro back in 1978. Not only did it read out speed and engine RPM but I programmed each of the LEDs to come on at different engine RPMs; one for normal range, one for orange line and one for red line of the engine. Because it is a relative sophisticated circuit using TTL chips, it is a rats nest of wires and circuit boards inside. The display units are actually fiber optic, not LED, output displays.
