Arduino: build a line-following robot
A 2WD robot that follows a black electrical-tape line using three IR reflectance sensors. Bang-bang control done honestly, PID optional.
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#arduino
43 tutorials
Arduino: a full traffic light with pedestrian button
Build a traffic light with a pedestrian crossing button using a proper state machine. The project that teaches event timing without delay().
Arduino: Simon-says memory game
Build the Simon memory game with 4 buttons, 4 LEDs, and a buzzer. State machines, tone(), and the game loop that scales to any difficulty.
Arduino: motion-activated night security light
A real outdoor-style light: PIR triggers, an LDR confirms it is dark, a relay drives a 12V lamp. The AND logic that stops false triggers.
Arduino: build a light-following robot with LDRs
A 2WD robot that chases a flashlight beam using two LDR eyes and bang-bang steering. Phototaxis for twelve dollars of parts.
Arduino: read a 4x4 membrane keypad with 8 pins
Read a 4x4 keypad with 8 Arduino pins instead of 16 by scanning rows and columns. The matrix-scan trick behind every keyboard ever made.
Arduino: animations on an 8x8 LED matrix (MAX7219)
Drive an 8x8 LED matrix with a MAX7219 and Arduino. Build frame-based animations: a smiley, a wave, and a scrolling pixel text. One chip, three wires.
Arduino: real timekeeping and alarms with the DS3231 RTC
Give your Arduino a real clock with the DS3231 RTC module. Set the time, read it back, and fire alarms that survive power loss, drift, and reboot.
Arduino: control it from an Android app with MIT App Inventor
Drive an Arduino over Bluetooth from an Android app you build yourself with MIT App Inventor, no Java, one HC-06 module, two-way control.
Arduino: build a digital clock with DS3231 + OLED
Build a desk clock that never drifts: a DS3231 RTC keeps time, a 0.96 inch SSD1306 OLED shows it big. Two I2C devices on the same two wires, plus a button to set it.
Arduino: long-range 2.4 GHz radio links with nRF24L01
Two Arduinos talking over 2.4 GHz with nRF24L01 modules, no WiFi, no phone, one capacitor and a library. Sensor links that run for months.
Arduino: electronic dice roller with 7-segment display
Roll a die with a button press: a 7-segment display shows 1 to 6 with a tumble animation. Direct-drive wiring, a segment map, and honest randomness on the Uno.
Arduino: Ethernet web server when Wi-Fi is not an option
Put an Arduino on your LAN with a W5500 Ethernet module and serve sensor pages from any browser. The wired path when Wi-Fi drops, roams, or is not allowed.
Arduino: location and time from a NEO-6M GPS module
Read latitude, longitude, and the exact UTC time from a $12 NEO-6M GPS module over serial. Wiring, the TinyGPS++ library, and why the fix takes 5 minutes outside.
Arduino: build a digital scale with a load cell and HX711
Turn a $8 load cell into a working digital scale with the HX711 amp and an Arduino Uno. Wiring, the calibration step everyone skips, and 1 g resolution.
Arduino: decode any IR remote with the IRremote library
Wire a 3-pin IR receiver to an Arduino and decode any TV or AC remote with the IRremote library. NEC, Sony, RC5, and the switch statement that turns buttons into actions.
Arduino: build an obstacle-avoiding robot from scratch
A 2WD Arduino robot that drives forward and dodges what is in front of it, using an HC-SR04 on a servo and an L298N driver. The full build, wiring to behavior.
Arduino: read high temperatures with a K-type thermocouple and MAX6675
Wire a K-type thermocouple and a MAX6675 to an Arduino and read oven, kiln, and solder-pot temperatures up to 1024 C. Includes the polarity trap.
Arduino: read water quality with the TDS module
Measure total dissolved solids with the Gravity TDS module on an Arduino: clean wiring, temperature compensation, calibration, and what TDS cannot tell you.
Arduino: voice control with a DFPlayer or voice-recognition module
Voice control on Arduino without the cloud: the DF2301Q offline voice module drives lights and sounds, and a DFPlayer Mini gives the project a voice back.
Arduino: build a gas alarm with the MQ-2
Build an MQ-2 gas and smoke alarm on an Arduino: wiring, warm-up, calibration, buzzer code, and the honest limits of a DIY detector.
Arduino: line-follower with the TCRT5000 array and PID
The PID line-follower: three TCRT5000 analog sensors feed one weighted error signal, and the robot steers in proportion to how far off the line it is.
Arduino: microwave radar motion detection with the RCWL-0516
Detect motion through walls and plastic with the RCWL-0516 microwave radar module. Doppler sensing that ignores temperature, sunlight, and thin drywall.
Arduino: datalogger with RTC + SD card for timestamped sensor files
Log sensor readings to an SD card with real timestamps from a DS3231 RTC. CSV files your spreadsheet opens directly, and a clock that survives power cuts.
Arduino: receive 433 MHz RF remote signals and replay them
Sniff, decode, and replay 433 MHz RF remotes (wireless doorbells, plug sockets) with a superheterodyne receiver and RCSwitch. One Arduino, two boards.
Arduino: drive a 4-digit display with the TM1637
Wire a TM1637 4-digit 7-segment display to an Arduino and print numbers, a clock, and a scrolling counter. Two pins, one library, no soldering.
Pico: program the Pico with the Arduino core (when C++ is the right tool)
Install the arduino-pico core, upload a blink sketch, and learn when the Pico deserves C++ instead of MicroPython: interrupts, timing precision, and memory headroom.
Arduino: persist data with EEPROM, the right way
Save a calibration value or a small setting to EEPROM so it survives a power cycle. The 1 KB on the Uno is enough for hundreds of values if you use it carefully.
Arduino: read a rotary encoder, position and direction
Wire a rotary encoder to two interrupt pins and track position, direction, and speed. The pattern that lets a motor know where it is.
Arduino: drive a DC motor with the L298N H-bridge
Wire an L298N module to an Arduino and control a DC motor forward, reverse, and at variable speed with PWM. The H-bridge pattern that runs most hobby robots.
Arduino: hardware interrupts, the right way to react to events
Wire a button to an interrupt pin and react to it instantly. The pattern that makes pin-change detection feel like magic, and the rules you cannot break.
Arduino: read an HC-SR04 ultrasonic distance sensor
Wire an HC-SR04 to an Arduino and read distance in centimeters. The 40 kHz chirp, the trigger pulse, the echo timing, and the math that turns a microsecond count into a number you can use.
Arduino: the watchdog timer, recover from hangs automatically
Add a watchdog timer to your Arduino sketch so the chip resets itself when it hangs. The pattern that keeps field-deployed projects from being bricked by a stuck sensor.
ESP32: install the toolchain the right way
Set up the Arduino IDE for ESP32 the way that does not break six months from now. Boards manager URLs, USB drivers, and the port detection traps.
Arduino: drive a 28BYJ-48 stepper motor with a ULN2003 driver
Wire a small stepper motor to an Arduino using the ULN2003 driver board. Precise position control without the expensive hardware.
Arduino: control relays for home automation
Drive a relay module from an Arduino to switch mains-powered devices. The most common home automation building block, with all the safety stuff included.
Arduino: drive a 16x2 LCD display (with I2C backpack)
Add a 16x2 character LCD to your Arduino using the I2C backpack. Show text, custom characters, and read sensor values on a screen.
Arduino: read temperature with a DS18B20 one-wire sensor
Wire a DS18B20 temperature sensor to an Arduino using the OneWire protocol. Multiple sensors on one pin, accurate to 0.5C.
Arduino: use I2C to talk to sensors and displays
I2C is the two-wire protocol that connects most Arduino sensors. This tutorial covers the wiring, the address scan, and the most common gotchas.
Arduino: control a servo motor
Drive a hobby servo (SG90, MG996R) from an Arduino. The shortest path from Arduino to 'something moved.'
Arduino: read a potentiometer and print the value
Wire a 10k potentiometer to an Arduino analog pin and read its position with analogRead. The second project after blink.
ESP32: read a DHT22 temperature and humidity sensor
Wire a DHT22 to an ESP32, install the library, and stream readings over Serial every 2 seconds. The shortest useful ESP32 project.
Arduino: blink an LED (the classic first project)
The minimum Arduino sketch. Blink the onboard LED on pin 13. If you have never programmed an Arduino, start here.