The keypad uses an onboard ATMega328P to scan the matrix for button presses, decode them, and send them via UART or I²C to an Arduino. [ELECTRONOOBS] has the PCB files available via Patreon for ...

If you’ve ever wanted to make your own VU meter but were scared off by the signal process you need to study this tutorial. The one drawback to the hardware choices made here is that there are ...