Un-digital Thermometer

To go completely retro, we can use dials to represent information. The device below is an example. It is actually thoroughly digital; it uses a DS1302 digital thermometer and the dial is actually a servo motor controlled by an AVR mega8. The only outward indication that the thermometer is digital is a light in the ellipse under the dial that changes from blue to green to red with increasing temperature (I had to use a flash so you can’t see it). The servo motor is a motorized potentiometer, normally used for remote control volume adjustments on modern stereo receivers. I picked up a bunch for $1.00 each, and another set for $2.00 each. They contain a worm gear and a potentiometer for feedback all in a compact and easily mounted package.

The case is from a clock that my wife received as a corporate gift. I removed the cheesy clock mechanism with its fake pendulum, printed a thermometer face, and reused one of the clock hands.

From the back, you can see the motor of the potentiometer.