Week 6: Embedded Programming

First, starting off with our group assignment in which we compared microntrollers and performed blink tests on two different boards:

Group Assignment

Binary Code

This week, I found that understanding some computer and programming fundamentals was very helpful and actually fascinating. So I went about this week in a kind of winding way, mostly focusing on reading up on the basics and later experimenting with some programming on the Seeed Studio Xiao RP2040 to produce some basic soundwaves.

Binary is a base-2 number system representing numbers using a pattern of ones and zeroes. Early computer systems had mechanical switches that turned on to represent 1, and turned off to represent 0. By using switches in series, computers could represent numbers using binary code.

Each digit in a binary number is called a bit, and each bit represents a power of 2. Binary code is the foundation of all digital technology and computing systems. In computers, binary code is used to represent data and instructions because it can be easily interpreted by electronic circuits that can distinguish between high and low voltage levels, corresponding to the binary digits 1 and 0, respectively.

3D printing is the manufacturing of solid objects by the deposition of layers of material (such as plastic) in accordance with specifications that are stored and displayed in electronic form as a digital model.

HIGH = 1
LOW = 0

By arranging these binary digits in different patters, complex data such as text, images, and sound can be represented and processed by computers.

A logic gate is a device that performs a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. The primary way of building logic gates uses diodes or transistors acting as electronic switches.

There is a world of information out there and further resources for individual study and practice. Just getting an understanding of the very basics of computers and programming was something I was needing to also "get" computer logic better and see how it's reflected in code and programming languages.

Here are some links I found helpful:

Binary system basics

Fab Lab Barcelona's code examples

How computers store information

Logic levels

Electronics tutorials page

Blink test and beyond

This week we compared microcontrollers and performed a blink test using our Quentorres boards we milled previously, whch is equipped with the Seeed Studio Xiao RP2040. We also tested it on our Barduino boards equipped with the ESP32. You can reference the Group Assignment to find it layed out. I stuck with the Arduino UNO and made a basic synthesizer.

Building a Basic Synthesizer

Materials needed:

Seeed Studio XIAO RP2040 board or Arduino UNO board

Breadboard

Jumper wires

Piezo buzzer or speaker (for sound output)

Potentiometer (optional, for adjusting pitch or volume).

Basic step by step Guide

Connect the Components: Connect the piezo buzzer or speaker to one of the digital pins (e.g., GPIO0) on the XIAO RP2040. If using a potentiometer, connect it to an analog pin (e.g., A0) to control pitch or volume.

Write the Synthesizer Code: Choose your preferred programming environment (Arduino, MicroPython, or CircuitPython). Write a program that generates sound tones by toggling the digital pin connected to the buzzer. You can create simple waveforms (sine, square, triangle) by varying the pin state at specific frequencies.

Generate Sound Tones: Use pulse-width modulation (PWM) to create different frequencies. Adjust the PWM duty cycle to change the pitch of the sound. Experiment with different frequencies to create musical notes.

Optional: Add Potentiometer Control: If using a potentiometer, read its analog value using analogRead(). Map the analog value to a frequency range (e.g., 200 Hz to 2000 Hz) for pitch control. Adjust the volume by mapping the analog value to PWM duty cycle.

Upload the Code: Upload your synthesizer code to the XIAO RP2040 or Arduino UNO. You should hear sound tones from the piezo buzzer or speaker.

Experiment and Enhance: Play around with different waveforms (square, sawtooth) for varied sounds. Add more features like envelope shaping (attack, decay, sustain, release) for more realistic tones. Explore MIDI input/output for connecting your synthesizer to other devices.

Code to generate soundwave using Arduino IDE:

// Generate a square wave on pin 9
  digitalWrite(28, HIGH); // Set the pin high
  delay(1);            // Half period duration (adjust as needed)
  digitalWrite(28, LOW);  // Set the pin low
  delay(1);            // Half period duration (adjust as needed)

In the above image, the beeping is continuous, so I added a button in order to control the sound.

I also experimented with getting a reading on an Oscilloscope using the setup of a Fab Lab member who was working on a pre-amplifyer.

Finally, I experimented on producing sounds with the touch sensors on the Barduino board and triggered different beeps:

Here's the code for the Barduino touch sensor tests:

void setup() {
  // Set pin 9 as an output
  pinMode(4, INPUT);
  pinMode(5, INPUT);
  pinMode(6, INPUT);
  pinMode(7, INPUT);
  pinMode(1, OUTPUT);
  Serial.begin(115200);
}
void loop() {
  int touch = touchRead(4);
  Serial.println(touch);
  delay (1);
  if (touch >=30000){ 
    digitalWrite(1, HIGH);
    delay(1);
    digitalWrite(1, LOW);
    delay(1);}
else {
  digitalWrite(1, LOW);  // Set the pin low
  delay(1);            // Half period duration (adjust as needed)
}
  int touch1 = touchRead(5);
  Serial.println(touch);
  delay (1);
  if (touch1 >=30000){ 
    digitalWrite(1, HIGH);
    delay(10);
    digitalWrite(1, LOW);
    delay(10);}
else {
  digitalWrite(1, LOW);  // Set the pin low
  delay(10);            // Half period duration (adjust as needed)
}

  int touch2 = touchRead(7);
  Serial.println(touch);
  delay (1);
  if (touch2 >=30000){ 
    digitalWrite(1, HIGH);
    delay(0.5);
    digitalWrite(1, LOW);
    delay(0.5);}
else {
  digitalWrite(1, LOW);  // Set the pin low
  delay(0.5);            // Half period duration (adjust as needed)
}
}