Week 04 - Embedded Programming

 Posted on February 17, 2026  |  

This week’s assignment was focused on embedded programming using a microcontroller.
The main goals was to learn how to:

  • browse and understand a microcontroller datasheet
  • write and test a program for an embedded system
  • interact with local inputs/outputs
  • communicate with remote wired/wireless connections
  • upload working code and show a functional result

For my individual assignment, I used an Xiao ESP32 C3 development board, soldered male pin headers, and tested it on a breadboard by blinking an LED, then upgrading the circuit with a button input + Serial communication.

Hero Shots

P P

Group Assignment

Tools & Materials

Hardware

  • Xiao ESP32 C3 Dev board
  • Male pin headers
  • Breadboard
  • LED
  • Resistor (220Ω)
  • Push button
  • type-c cable (for power + programming)
  • Macbook Air

Software

  • Arduino IDE
  • ESP32 board package

Microcontroller Datasheet Research (ESP32)

Before writing code, I browsed an ESP32 datasheet (https://documentation.espressif.com/esp32_datasheet_en.pdf) to understand what I am programming and what features the board offers.

I also got help from this more user friendly guide for Xiao ESP32 C3:

P

Key features:

  • GPIO pins: ESP32 has many programmable pins used for input/output
  • PWM support: allows dimming LEDs and controlling motors
  • Wi-Fi + Bluetooth: built-in communication features
  • Multiple power modes: useful for battery powered projects
  • 3.3V logic: important because ESP32 pins are not 5V tolerant in most cases

What I learned from the datasheet:

  • ESP32 pins can behave differently depending on boot mode
  • Some GPIO pins are “special” pins used for booting, flash programming, etc.
  • ESP32 is designed for projects that need both processing + wireless communication, which makes it suitable for my final project plans.

Preparing the ESP32 Board (Soldering Headers)

My ESP32 board came without soldered pins, so I first had to solder male pin headers.

Steps I followed:

  1. Placed the male pin headers into the breadboard (to keep them straight)
  2. Positioned the ESP32 board on top of them
  3. Soldered each pin carefully, checking alignment constantly
  4. Inspected solder joints to ensure:
    • no bridges between pins
    • shiny and solid connections
    • strong mechanical stability

This step was important because without headers, I couldn’t reliably connect the board to a breadboard for prototyping and programming.

Checking the solder:

P

Circuit 1 — Blink LED Test (Local Output)

After soldering, I moved on to a simple embedded test: blinking an LED.

Circuit setup

  • One LED leg (anode) connected to a GPIO pin
  • The other LED leg (cathode) connected to GND
  • A resistor was added in series to protect the LED

P

My wiring logic:

  • The ESP32 turns a pin HIGH → LED turns ON
  • The ESP32 turns a pin LOW → LED turns OFF

Circuit 2 — Button Input + Serial Communication (Input + Output + Wired Communication)

After confirming the ESP32 worked with the blink test, I upgraded the circuit to include:

Local input: push button
Local output: LED
Wired communication: Serial Monitor (type-c)

  • In terms of wiring a push button with 2 legs is added. One of its leg to a gpio pin and the other is to ground.

P

Circuit logic

  • When I press the button → ESP32 reads the input
  • ESP32 turns the LED ON/OFF
  • ESP32 prints the state to Serial Monitor

Programming Process

Installing ESP32 Support in Arduino IDE

To program ESP32 using Arduino IDE, I first installed the ESP32 boards manager.

Steps:

  1. Open Arduino IDE
  2. Go to Preferences
  3. Add ESP32 Board Manager URL (It is in the datasheet)
  4. Go to Boards Manager
  5. Install esp32 by Espressif Systems

Then I selected:

  • Board: ESP32 Dev Module
  • Port: the detected USB serial port

Note: Be sure that you chose the correct board as there are many board to chose from with similar names. At first I did that mistake :P

How Arduino Ide Looks:

P

Source Code

Code 1 — Blink LED

// Fab Academy Week 04 - Embedded Programming
// ESP32 Blink Test

int ledPin = 2;  // GPIO 2

void setup() {
  pinMode(ledPin, OUTPUT);
}

void loop() {
  digitalWrite(ledPin, HIGH);
  delay(500);

  digitalWrite(ledPin, LOW);
  delay(500);
}

Code 2 — Button + Serial Communication

// Fab Academy Week 04 - Embedded Programming
// ESP32 Button + LED + Serial Communication

int ledPin = 2;      // GPIO 2
int buttonPin = 4;   // GPIO 4

void setup() {
  pinMode(ledPin, OUTPUT);
  pinMode(buttonPin, INPUT_PULLUP);  // internal pull-up

  Serial.begin(115200);
  delay(1000);
  Serial.println("ESP32 Button + LED Test Started");
}

void loop() {
  int buttonState = digitalRead(buttonPin);

  if (buttonState == LOW) { // pressed
    digitalWrite(ledPin, HIGH);
    Serial.println("Button Pressed -> LED ON");
  } else {
    digitalWrite(ledPin, LOW);
    Serial.println("Button Released -> LED OFF");
  }

  delay(100);
}

Testing and Results

After uploading the codes to the ESP32, the board successfully ran the programs

The LED blinked continuously (Circuit 1)

Video:

The button correctly controlled the LED (Circuit 2)
Serial Monitor printed live status messages (Circuit 2)

Video:

This confirmed:

  • the ESP32 was properly powered
  • my header soldering was correct
  • my wiring was correct
  • I could compile and upload code successfully

Reflection

This week helped me understand the full process of embedded programming from scratch:

  • hardware preparation (soldering headers)
  • wiring and testing on a breadboard
  • programming through Arduino IDE
  • writing and uploading code
  • basic output behaviors
  • adding input + communication for a more complete embedded system test

The biggest takeaway for me is that embedded programming is not only “writing code”, but also combining hardware setup + correct wiring + understanding what the microcontroller is capable of.

This was an important foundation week because I will need these skills when I start building more advanced outputs (RGB LEDs, displays, and sound) for my final project.