Real projects you can open and remix

An HC-SR04 ultrasonic sensor and a buzzer that beeps faster as things get closer. Live-simulatable, great first project.

Soil moisture + DHT11 climate readings on an OLED, with a dry-soil buzzer alert. A real multi-sensor build.

A DHT22 sensor streaming live temperature and humidity onto a 0.96" OLED. The classic I2C display starter.

A rotary encoder cycles an RGB LED through smooth colours, press the knob to freeze the one you like.

Raspberry Pi Pico starter: an LED blinks until you hold the button. Runs truly live in the in-browser simulator.

LED lights after a random delay, hit the button as fast as you can and read your milliseconds on the Serial Monitor.

A photoresistor senses the dark and fades an LED in smoothly, the classic automatic night light.

Red, yellow and green LEDs run a real signal sequence, and a pedestrian button requests a crossing.

An HC-SR04 rides a sweeping servo and prints angle + distance, the makings of a cardboard radar.

Press the button, get a tune: a piezo buzzer plays a short melody with tone(). Arduino Nano flavoured.

The classic memory game: watch the LED sequence, repeat it on the buttons, and survive ever-longer rounds.

A 25/5 focus timer on a 16x2 LCD with a start button and a buzzer that marks every break.

Wave your hand over the photoresistor and the buzzer's pitch follows the shadow, an instrument in 3 parts.

Type a word into the Serial Monitor and watch the LED + buzzer flash it back in real Morse code.

Press to roll: a dice face tumbles on the OLED and lands on your number. Sneaky randomSeed trick included.

A potentiometer smoothly dims an LED on the Raspberry Pi Pico, twist the knob live in the simulator.

Twist the potentiometer, the servo follows, the friendliest possible introduction to motion control.

A random LED pops up, smack its button before it vanishes. Score and speed-up rounds on the Serial Monitor.

Four buttons, four notes, plus an octave-shift key, a pocket piano on a piezo buzzer.

Two buttons drive the paddle in a real Pong-against-the-wall on the OLED, ball physics, score and speed-ups.

Six LEDs sweep Knight-Rider style; a rotary encoder tunes the speed and its button flips patterns.

A servo gauge needle sweeps with distance while an RGB LED shifts green→amber→red and the buzzer closes in.

Three LEDs blink at independent rates with zero delay(), the millis() pattern every real project is built on.