Now for the minutiae: there’s an Arduino Uno with built-in Wi-Fi that receives UDP commands from a phone to raise and lower the clock at the appropriate times. The ‘duino is also controlling ...

and an Arduino Uno R3 with an ATmega328P. To do that, he took a bench PSU, added a filter circuit to it, went through the entire ADC range for each board, took a large number of samples at ...