Digital Speedo Built for Datsun 1200

The project was built in 1995 which aims to replace the unreliable analog speedometer of a 1971 Datsun 1200.

The construction uses a PCB for the power regulation and input circuitry which is connected to the output display using some lengths of multi-core data cable. A 7-core data cable connects the PCB and breadboard. The PCB and breadboard were installed under the center console in the Datsun and on top of the dash is the output display located in the line-of-sight.

A 4-digit 7-segment display that uses 16mm high digits is taken from an electronic alarm clock to create the output display. To keep the direct sun off the display, a small shade visor was made out of thin card with black paint inside as it ensure the eligibility of the display in bright sunlight.

Just behind the gear box are two strong magnets attached to the opposite sites of the tailshaft. The sensor is created using a coil taken from a solenoid from some electro-mechanical device. To provide an easy method of mounting it underneath the car, the coil was screwed to a section of aluminum plate with silicone coating.

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