Arduino projects, step by step_

• Your inventoryAdd the parts you own and see which projects you can build right away.
• Wire by wireTick off every connection; one wire in the wrong hole is where most first builds fail.
• Shopping listWhatever you are missing, in one list with the quantities.

Projects

• LED BlinkBeginner10 minYour first project: it blinks an LED on the Arduino's pin 13 once a second and writes each change to the Serial Monitor. It teaches you to use a breadboard, an LED and a resistor. The board's own L light is also on pin 13, so it blinks along with the LED. No extra library needed.Open project
• Night Light (LDR)Beginner20 minA night light that turns itself on as the room gets dark. An LDR (light sensor) and a 100 kΩ resistor form a voltage divider; the Arduino reads the light level on pin A0 and, in the dark, dims the LED on pin 9 with PWM. It teaches analog reading, thresholds and PWM. No extra library needed.Open project
• DHT11 Temperature and Humidity MeterBeginner20 minA starter project that measures the room's temperature and humidity with a DHT11 sensor and writes the values to the Arduino IDE's Serial Monitor once a second. Before uploading the code, install the DHTlib library in the Arduino IDE.Open project
• DHT22 Temperature and Humidity MeterBeginner20 minA project that measures humidity and temperature, in both Celsius and Fahrenheit, with a DHT22 sensor and writes them to the Serial Monitor every two seconds. It is more precise than the DHT11 and has a wider measuring range. Before uploading the code, install Adafruit's "DHT sensor library" in the Arduino IDE (and the "Adafruit Unified Sensor" library it asks for).Open project
• HC-SR04 Ultrasonic Distance MeterBeginner20 minA project that measures the distance to the object in front of an HC-SR04 ultrasonic sensor in centimetres and writes it to the Serial Monitor about 10 times a second. The sensor measures how long the echo of its sound wave takes to come back; the code turns that time into centimetres by dividing it by 58. No extra library needed.Open project
• Alcohol Measurement with the MQ-3 SensorBeginner25 minA project that measures alcohol vapour in the air with an MQ-3 gas sensor and writes the analog value and the threshold state to the Serial Monitor every half second. The analog value (0-1023) rises as the alcohol concentration goes up; the Limit value shows whether the threshold set with the trimmer on the board has been crossed. No extra library needed. The sensor's heater gets warm while it runs; on first use, leave the sensor powered for a while (ideally 24 hours), and let it warm up for a few minutes before measuring. The code uses 115200 baud, so pick 115200 in the Serial Monitor too.Open project
• LPG Gas Measurement with the MQ-5 (PPM)Intermediate30 minA project that reads the MQ-5 gas sensor's analog output, turns it first into a voltage and then into the ratio of the sensor's resistance to its resistance in clean air (Rs/Ro), and writes an estimated LPG concentration (PPM), worked out with the datasheet curve formula, to the Serial Monitor every two seconds. At start-up it waits 10 seconds for the heater to settle. In clean air the ratio is high and the PPM low; with gas around, the ADC and PPM values rise clearly. The PPM value is an estimate: for an accurate result, calibrate the sensor in clean air and update the Ro value. No extra library needed.Open project
• Level Measurement with a Water Level SensorBeginner15 minA starter project that reads the water level sensor's analog output and writes the level as Empty, Low, Medium or High to the Serial Monitor once a second. As the sensor's parallel tracks go under water, the resistance drops and the reading rises. The thresholds (100, 400, 450) depend on the water's conductivity and the sensor; watching the raw values first and setting your own thresholds gives better results. Only dip the lower part with the tracks in water; keep the electronics and pins at the top dry. To reduce corrosion, do not leave the sensor powered all the time. No extra library needed.Open project