This is an interesting voltmeter project that display the measured voltage on a TV screen, in giant digits as well as with analog bar. It also records the maximum and minimum values of measurements. The project was built by Alberto Ricci Bitti and was published in the May 1999 issue of Elektor Electonics.
The circuit uses Atmel’s AVR 90S1200 microcontroller with the Maxim’s MAX192 analog to digital converter that has 8 channels multiplexer for its 10-bit ADC. The hardware to generate the composite video signal is extremely simple; the complexity goes to the software part because the video synthesis requires very accurate timing measurements.
This free embedded project also found using:
- block diagram of digital voltmeter using atmega microcontroller