Clock System Using 3 Analog Panel Meters

With three analog panel meters, the project was able to display a time connected to the Internet.

The computing platform is provided by the Arduino which gets easily connected to an SNTP time server using the Adafruit Etherne Shield while the interface circuitry for the analog meters is made possible by the Adafruit Proto Shield.

A simple driver board is the only real hardware design which contains three meter drivers. The Arduino board contains the 3 different PWM channels for connecting one for each meter. Two potentiometer adjustments are available on each meter driver wherein the MAX adjustment sets the meter into full scale deflection and the ZERO adjustment sets the meter to read 0. A single op-amp is used for each meter driver to sum two signals, select them, and the result is outputted to the meter.

The 3 analog panel meters came from a surplus wherein the 0-5 AMP meter was a shunt between the input terminals of the meter needed to be removed and a new resistor needed to be put in series with the movement. Clipping the shunt and replacing the resistor creates a different meter face.

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