Digital pins can normally only output HIGH or LOW. Using the Arduino UNO R4’s fast clock, we drive all 20 pins with Software PWM to render three different waves of light — complete with gamma correction and full source code.
A complete guide to controlling full-color RGB LEDs with Arduino PWM. From basic 8-color digital output to smooth 16.7 million color gradients using three-phase sine waves — with circuit diagrams and ready-to-use sample code.
Read sensor voltages with the Arduino ADC and stream them to the serial monitor in real time. Covers 10-bit vs. 14-bit resolution, the voltage conversion formula, and PWM output — with code that runs on both R3 and R4.
Build a playable electronic piano with an Arduino UNO R4 and a passive piezo buzzer. Complete with a note-to-frequency table, circuit diagram, annotated code, demo videos, and an FAQ covering the usual pitfalls — finished in about an hour.