Your first five projects

Start with project 1 and work your way up. Each one follows the same pattern: sense → think → act, and the last one adds share.

Project 1: Automatic night lamp

1. Connect the LDR and 10 kΩ resistor in a line between 5V and GND; join their middle point to pin A0.
2. Connect the LED and 220 Ω resistor from pin 13 to GND.
3. Upload the night-lamp code from Chapter 7.
4. Cover the LDR with your hand. The LED should switch on!

Project 2: Intruder alarm

1. PIR pins: VCC to 5V, GND to GND, OUT to pin 2.
2. Buzzer to pin 8, LED (with resistor) to pin 13.
3. Code idea: if pin 2 is HIGH, then turn on the buzzer and LED for 3 seconds.
4. Wait one minute after powering on; the PIR needs time to settle.

Project 3: Thirsty-plant alarm

1. Sensor: VCC to 5V, GND to GND, AOUT to A0.
2. Read the number with the sensor in dry soil, then in wet soil.
3. Code idea: if the reading says "dry", then beep twice every minute.
4. Level up: later, add a relay and a small pump so the plant waters itself.

Project 4: Smart dustbin

1. Ultrasonic: VCC to 5V, GND to GND, TRIG to pin 9, ECHO to pin 10.
2. Servo: brown to GND, red to 5V, orange to pin 6.
3. Code idea: if a hand is closer than 20 cm, then turn the servo to 90° (lid open), wait 3 seconds, then back to 0°.
4. Tape the servo arm to the lid and the sensor to the front of the bin.

Project 5: Phone-controlled light

1. Create a Blynk account and a new device template.
2. Connect the LED and resistor from GPIO 2 to GND (many ESP32 boards also have a built-in LED on GPIO 2).
3. Upload Blynk's example code with your WiFi name, password and Blynk details filled in.
4. Add a button in the app linked to the LED. Tap it, and your light turns on through the internet!

Congratulations: project 5 is a real IoT device. It senses your command, thinks, acts and shares over the internet.