Build an Obstacle-Avoiding Robot
A complete build with parts list, wiring table and full Arduino code for a two-wheel robot that scans with an ultrasonic sensor and steers around obstacles.
→ misses chair legs, raise STOP_CM
section 8, the grey band
Projects
Complete builds with parts lists, wiring and code.
Automatic Plant Watering System
Build a soil-moisture-controlled watering system with a capacitive sensor, a relay or MOSFET, a small pump and Arduino code with safety limits.
→ limit waterings per day!
Digital Thermometer with an OLED Display
Build a waterproof digital thermometer with a DS18B20 probe and a 0.96 inch SSD1306 OLED, showing live temperature plus the minimum and maximum.
→ blank screen? try address 0x3D
Build a Reaction-Time Game
A two-button Arduino game that waits a random time, lights an LED and measures who reacts first in milliseconds, with anti-cheat and a buzzer.
→ use millis(), and catch early presses
Build an Arduino Parking Sensor
A garage parking assistant with an HC-SR04 sensor, a buzzer that beeps faster as you get closer and LEDs that go from green to red.
→ map distance to beep interval, not delay()
Build a Bluetooth-Controlled Robot Car (HC-05)
A complete build of a two-wheel robot car you drive from an Android phone, with parts list, safe HC-05 wiring, motor driver connections and full Arduino code.
→ divide the TX line down to 3.3 V
Build an Arduino Weather Station with a BME280 and OLED
A compact indoor weather station that shows temperature, humidity, pressure and a simple forecast trend on an OLED, with parts list, I2C wiring and full Arduino code.
→ BMP280 ≠ BME280: check before you buy
Build an RFID Door Lock with Arduino (RC522 and a Servo)
A complete RFID lock project: read cards and key fobs with the RC522 module, check them against a list of allowed IDs, and unlock a servo latch with LED and buzzer feedback. Full wiring and code.
→ The RC522 runs on 3.3 V, not 5 V
Build an Arduino Clock with a DS3231 RTC and OLED Display
A desk clock that keeps accurate time even when unplugged, using the DS3231 real-time clock module and an SSD1306 OLED. Wiring, setting the time, full code and the ZS-042 battery warning.
→ Check the battery circuit before inserting a CR2032
Build a Temperature-Controlled Fan with Arduino (DS18B20 + MOSFET)
A fan that speeds up as it gets warmer: DS18B20 sensor, logic-level MOSFET and PWM speed control, with a fan curve, hysteresis, kick-start, silent 31 kHz PWM and a fail-safe. Full wiring and code.
→ Fail safe: if the sensor dies, the fan runs at full speed
Arduino Traffic Light with Pedestrian Button (Beginner Project)
Build a realistic traffic light with a pedestrian crossing: five LEDs, one button, and code that uses a state machine and millis() so the button always responds. Parts list, wiring and full code.
→ The button works at any moment because nothing uses delay()
Arduino Water Tank Level Monitor with HC-SR04 and LCD
Build a water tank level indicator with an HC-SR04 ultrasonic sensor, a 16x2 I2C LCD and a buzzer. Shows the level in percent and liters with a bar graph, filters bad readings and sounds a low-level alarm.
→ keep the sensor 5 cm above full water
Arduino Radar: Sweep an HC-SR04 with a Servo and Show It on an OLED
Build a mini sonar radar with an SG90 servo, an HC-SR04 ultrasonic sensor and a 0.96 inch SSD1306 OLED. Wiring, the full sketch that draws range rings, a sweep line and detected objects, and how the polar-to-screen math works.
→ angle + distance → x, y on the screen