Hands-on Introduction to Arduino and ESP32: Wiring, Coding, and Testing Sensors Through Small Experiments.

This project documents the first two weeks of our mechatronics coursework, where we focused on learning by doing. Starting with a breadboard, LEDs, and simple resistive circuits, we gradually introduced microcontrollers (Arduino UNO and ESP32) to interface with sensors, actuators, and displays. Each small experiment—whether blinking an LED, reading ultrasonic distance, or logging temperature to the cloud—built our understanding of electronics, coding, and system integration.

By the end of these sessions we had:

1. Practiced safe wiring and current-limiting on breadboards
2. Controlled LEDs with potentiometers, transistors, and 555 timers
3. Programmed Arduino for basic I/O, PWM brightness, and RGB mixing
4. Worked with sensors such as ultrasonic, IR, gas, soil moisture, and DHT (temperature & humidity)
5. Explored ESP32 features including Bluetooth Low Energy, OLED displays, and cloud logging via ThingSpeak and MIT App Inventor
6. Designed simple PCBs to consolidate our circuits for easier prototyping

This Instructable serves as a step-by-step record of those assignments, giving beginners a roadmap for building a solid foundation in microcontroller-based mechatronics.

The videos document our basic sensor and control experiments with Arduino. We tested a gas sensor, displaying real-time readings on an LCD. When smoke is introduced, the value rises, a red LED lights, and a buzzer sounds. Additional clips show Bluetooth-based control, toggling a single LED on/off and then extending the same setup to independently switch three LEDs.

During the first two weeks we completed a series of small, progressive exercises to build our mechatronics fundamentals. The assignments moved from basic LED circuits to Arduino/ESP32 sensor work and simple PCB design. Here’s the full list of experiments included in this guide:

1. Breadboard LED circuits (single LED, series, parallel, brightness with potentiometer)
2. LED control using NPN transistor and 555 timer
3. Push-button and RGB LED experiments
4. Arduino basics: LED blink, push-button, PWM brightness, RGB control
5. Arduino with sensors: ultrasonic + LCD, ultrasonic + LCD + servo, IR + buzzer, NeoPixel, gas sensor with LCD & buzzer
6. ESP32 projects: BLE LED control, OLED display, DHT + ThingSpeak + MIT App, DHT + OLED, soil-moisture + DHT + gas sensor dashboard, BLE control of 3 LEDs
7. PCB work: RGB LED driver PCB, ESP32 sensor interface PCB (KiCad design, etching, testing)