Digital Tachometer

This digital tachometer was made from a Maplins electronics kit.

The display unit only had 2 digits and the standard design displayed speed in hundreds and thousands of revolutions.

A x10 converter disc was made to give greater output sresolutiona st lower speeds.

The disc had 10 light/dark contrast areas to give 10 pulses per revolution. This made the display show tens and hundreds of revolutions.

The System Components.

A signal indicator was added to the input line. This green LED flashed for each pulse received from the transducer. It was usful during set up to ensure the tranducer was positioned correctly.

The sensor was an infra-red transceiver/receiver which was mounted on a magnetic base with an adjustable angle.









This photo shows the rev-counter in action.

The x10 converter was used with the Stirling engine to test the tachometer.

The image shows the engine running at about 310 revs/minute.

Tachometer Measuring the Stirling Engine Speed.