What is the voltage on a AA battery? It would be around 1:30PM if you were using this voltmeter! A PICAXE 18M2 microcontroller is used to read an analog value, calculate what time it represents and then uses a stepper motor to spin the adjustment knob to have the clock show the voltage using the hour and minute hands. 🙂
Read more about the Analog Clock Voltmeter
“The max input voltage for the ADC on the PICAXE 18M2 is about 5VDC.  To tame the input signal for the PICAXE a simple 3:1 voltage divider (10K, 10K, 10K) was implemented.  This limited the input voltage into the PICAXE to 4VDC.  A trim pot was also used to adjust for the input impedance of the PICAXE and to help calibrate the measurement results.”