Embedded programming

Group Assignment:

• Demonstrate and compare the toolchains and development workflows for available embedded architectures.
• Document your work to the group work page and reflect on your individual page what you learned

Individual Assignment:

• Browse through the datasheet for your microcontroller.
• Write a program for a microcontroller, and simulate its operation, to interact (with local input &/or output devices) and communicate (with remote wired or wireless connection)

What is embedded programming?

An embedded system (also known as “embedded”, “embedded” or “integrated”) is a computing system designed to perform specific functions, and whose components are integrated on a motherboard.

Group Assignment

Group assignment

Reflections

During the group project, I was able to learn more about embedded system architectures, such as toolchains and development workflows for embedded architectures. This involves analyzing how embedded systems are designed, developed, tested, and debugged using different environments. It was a very enriching project; it allowed me to learn and expand my knowledge, allowing me to better understand how different architectures work. Several years ago, I worked with PIC, one of the most classic and popular microcontrollers in the 8-bit PIC series. Although more modern models exist today, it is still very useful for learning basic concepts about embedded systems.

Individual Assignment

• Browse through the datasheet for your microcontroller.

For the development of this task I chose to work with Seeed Studio XIAO ESP32C3 which is a compact and powerful mini IoT development board based on the Espressif ESP32-C3 chip, below I will explore all its data sheet and technical information,For more details, please consult. ESP32C3 series datasheet

Introduction to Seeed Studio ESP32-C3

1.-Especifications

Category	Specification
Microcontroller	ESP32-C3 (32-bit RISC-V, up to 160 MHz)
Flash Memory	4 MB
SRAM	400 KB
Wireless	Wi-Fi 802.11 b/g/n (2.4 GHz) Bluetooth 5.0 (BLE + Mesh)
USB Interface	USB Type-C
GPIOs	11 digital I/O pins All GPIOs support PWM
ADC Channels	4 channels (12-bit resolution)
Interfaces	1 × UART 1 × I2C 1 × SPI
Operating Voltage	3.3 V
Power Supply	5 V via USB or external source
Current Consumption	Deep Sleep: ~44 µA Light Sleep: ~10 mA Active with Wi-Fi: ~75 mA
Charging Current	100 mA / 350 mA (configurable)
Reset Button	Yes
Boot Button	Yes
Dimensions	21 mm x 17.5 mm
Operating Temperature	-40 °C to 85 °C
Weight	2 g (approx.)
Development Support	Arduino, PlatformIO, ESP-IDF, MicroPython

2.-Features and details

3.-.-Hardware overview

4.-Pin Out

• Write a program for a microcontroller, and simulate its operation, to interact (with local input &/or output devices) and communicate (with remote wired or wireless connection)

Programming with the ESP32C3 microcontroller

Analyzing the technical characteristics of the XIAO ESP32C3 microcontroller from Seeed Studio, it is a miniature IoT development board based on the dual WiFi/Bluetooth ESP32-C3 chip from Espressif. The ESP32-C3 is a 32-bit RISC-V CPU, which includes an FPU (Floating Point Unit) for 32-bit single-precision arithmetic with high computing power. It has excellent radio frequency performance, supporting the IEEE 802.11 b/g/n WiFi and Bluetooth (BLE) protocols. This board includes an external antenna to increase signal strength in your wireless applications. It also has a small and exquisite format combined with a single-side surface mount design. It is equipped with rich interfaces and has 11 digital I/O pins that can be used as PWM pins and 3 analog I/O pins that can be used as ADC pins. Which will serve to develop my final project, which consists of designing and manufacturing a police robot to provide security.

Arduino IDE Loading Screen

To start developing our sketches, we must install the IDE provided by the Arduino project on our computer. We simply enter the following download link, select the file corresponding to our type and version of operating system (Windows, Mac OS, Linux) and follow the standard installation steps of any native application of our operating system.

Simulate LED lighting with button on ESP32-C3 (Wokwi)

Once we have the Arduino IDE installed, before working with the Arduino environment, we'll first simulate our circuit using Wokwi. The goal is to turn an LED on and off using a button. This circuit is quite simple, but we'll explain it step by step anyway.

• We are going to use a button connected to GPIO10 (D10).
• We will control an LED on GPIO2 (D0).
• When the button is pressed, the LED lights up.

The circuit is shown as follows

Simulation using HC-SR04 ultrasonic sensor, to measure distance and display it on serial monitor

The circuit is shown as follows

Explanation of the code

1. Define the sensor pins

#define TRIG_PIN 3  // Pin GPIO 03 of the XIAO ESP32C3
#define ECHO_PIN 2  // Pin GPIO 02 of the XIAO ESP32C3
										

• TRIG_PIN: Sends the ultrasonic pulse.
• ECHO_PIN: Listens for the returning echo.

2. Setup function

void setup() {
	Serial.begin(115200);
	pinMode(TRIG_PIN, OUTPUT);
	pinMode(ECHO_PIN, INPUT);
}
										

• Serial.begin(115200): Starts the serial monitor for debugging.
• pinMode(...): Sets TRIG as output and ECHO as input.

3. Loop function — measure distance continuously

void loop() {
										

🟢 Send the ultrasonic pulse

	digitalWrite(TRIG_PIN, LOW);
	delayMicroseconds(2);
	digitalWrite(TRIG_PIN, HIGH);
	delayMicroseconds(10);
	digitalWrite(TRIG_PIN, LOW);
										

• First, make sure the TRIG pin is LOW for 2 microseconds (stabilization).
• Then send a HIGH signal for 10 microseconds — this triggers the ultrasonic burst.
• Finally, set TRIG to LOW again.

⏱️ Measure echo duration

	long duration = pulseIn(ECHO_PIN, HIGH);
										

• pulseIn(...): Measures how long the ECHO pin stays HIGH (i.e., how long the sound took to bounce back).
• The value is returned in microseconds (µs).

📏 Convert time to distance

	float distance = duration * 0.034 / 2;
										

• The speed of sound is approximately 0.034 cm per microsecond.
• Divide by 2 because the sound travels to the object and back (round trip).

Print the result:

if (duration == 0) {
	Serial.println("No response from sensor");
} else {
	Serial.print("Distance: ");
	Serial.print(distance);
	Serial.println(" cm");
}						  

Simulation of XIAO ESP32-C3 with SSD1306 OLED display on Wokwi

For this simulation we will use the I2C communication protocol, which is a very common type of synchronous serial communication in electronics to connect microcontrollers with peripherals such as sensors, displays, memories, etc.

components to use

• SSD1306 OLED Display (I2C)
• HC-SR04 Sensor (distance)
• XIAO ESP32-C3

We will explain step by step

The circuit is shown as follows

explanation of the programming

1. At startup, the microcontroller configures the pins for the ultrasonic sensor and OLED display.
2. A startup message is displayed on the OLED to indicate the system is ready.
3. The microcontroller sends a short pulse (10 microseconds) to the TRIG pin of the HC-SR04 sensor.
4. The sensor emits an ultrasonic wave that bounces off the nearest object.
5. When the wave returns, the sensor sets the ECHO pin high; the duration of this signal represents the round-trip travel time of the sound wave.
6. The microcontroller measures that duration and calculates the distance using the formula:
   distance = (duration × 0.034) / 2
7. The measured distance is displayed on the OLED screen and also printed to the serial monitor.
8. This process repeats continuously every 500 milliseconds.

This operation allows real-time distance measurement of any object in front of the sensor. It's ideal for projects like proximity detectors, smart parking systems, robotics, and more.