VGA Monitor Used for Displaying Waveforms

The project aims to show how waveforms and signals can be displayed on a VGA monitor using a few resistors, capacitors, and an ATtiny84 microcontroller that runs at 20MHz.

The goal is to create a very simple circuit by using one of the smallest AVR, the ATtiny84 which has large memory of around 8k flash although physically small. To generate a vertical line on a VGA monitor, just one 20MHz crystal, one VGA connector, 4 resistors, and 5 capacitors are sufficient. Depending on the voltage and input pin of the microcontroller, this vertical line swings left to right. The line will dance if music is applied at the pin.

The device is capable of updating 800×600 VGA screen with refresh rate of 60Hz. Through ADC channel, it takes audio signals and displays it as a vertical waveform on the screen. An electret microphone can also be connected to the ADC channel using a specially designed preamp so that the coice can also be seen on the screen.

Instead of a regular TV, a VGA was chosen because it has no 60Hz vs 50Hz issue and is not interlaced which may add difficulty.