Creating a Radio Controller with ESP32 and Touchscreen Interface
===========================================================
As a hobbyist, I wanted to create a radio controller that could switch between different German stations using an ESP32 microcontroller and a touchscreen interface. In this project, I'll guide you through the steps of creating a custom radio controller that can easily switch between five different radio stations.
Hardware Components
-----------------
* ESP32 microcontroller
* 5x GPIO pins for input and output
* I2S amplifier board for converting digital audio signal to analogue
* 20W ClassD amplifier board for amplifying the audio signal
* Old available speaker inside the radio (optional)
* STM32 DISCO Development board with touchscreen LCD
Software Components
-----------------
* TouchGFX library for creating a graphical user interface
* STM32CubeIDE for programming the ESP32 microcontroller
* Custom code for switching between radio stations and handling touchscreen input
Step 1: Setting up the Hardware
------------------------------
First, let's set up the hardware components. I defined 5 pins of the microcontroller as inputs and added some simple lines of code to switch over to the selected radio station as soon as the corresponding pin gets connected to a high voltage.
```c
// Set up GPIO pins for input and output
const int radioPin1 = 2;
const int radioPin2 = 4;
const int radioPin3 = 5;
const int radioPin4 = 6;
const int radioPin5 = 8;
void setup() {
// Initialize GPIO pins as inputs
pinMode(radioPin1, INPUT);
pinMode(radioPin2, INPUT);
pinMode(radioPin3, INPUT);
pinMode(radioPin4, INPUT);
pinMode(radioPin5, INPUT);
// Initialize I2S pins for outputting digital audio signal
Serial.begin(115200);
}
void loop() {
// Read input from GPIO pins
int radio1 = digitalRead(radioPin1);
int radio2 = digitalRead(radioPin2);
int radio3 = digitalRead(radioPin3);
int radio4 = digitalRead(radioPin4);
int radio5 = digitalRead(radioPin5);
// Switch to selected radio station
if (radio1 == HIGH) {
// Code to switch to radio station 1
} else if (radio2 == HIGH) {
// Code to switch to radio station 2
} else if (radio3 == HIGH) {
// Code to switch to radio station 3
} else if (radio4 == HIGH) {
// Code to switch to radio station 4
} else if (radio5 == HIGH) {
// Code to switch to radio station 5
}
}
```
Step 2: Creating the Graphical User Interface
------------------------------------------
Next, I created a graphical user interface using TouchGFX library on the STM32 DISCO Development board. The UI consists of toggle buttons for each radio station that can be selected and deselected.
```c
// Create toggle buttons for radio stations
ToggleButton radio1Button(100, 200);
ToggleButton radio2Button(150, 200);
ToggleButton radio3Button(200, 200);
ToggleButton radio4Button(250, 200);
ToggleButton radio5Button(300, 200);
void setup() {
// Initialize UI components
radio1Button.begin();
radio2Button.begin();
radio3Button.begin();
radio4Button.begin();
radio5Button.begin();
// Add logic to switch to selected radio station when button is pressed
}
void loop() {
// Read input from UI buttons
if (radio1Button.isPressed()) {
// Code to switch to radio station 1
} else if (radio2Button.isPressed()) {
// Code to switch to radio station 2
} else if (radio3Button.isPressed()) {
// Code to switch to radio station 3
} else if (radio4Button.isPressed()) {
// Code to switch to radio station 4
} else if (radio5Button.isPressed()) {
// Code to switch to radio station 5
}
}
```
Step 3: Handling Touchscreen Input
--------------------------------
To handle touchscreen input, I defined additional GPIO pins as outputs and added a couple of lines of code to turn them on or off when the corresponding button is pressed.
```c
// Define additional GPIO pins for output
const int gpio1 = 10;
const int gpio2 = 11;
void setup() {
// Initialize GPIO pins as outputs
pinMode(gpio1, OUTPUT);
pinMode(gpio2, OUTPUT);
// Add logic to turn on or off GPIO pins when button is pressed
}
void loop() {
// Read input from UI buttons
if (radio1Button.isPressed()) {
digitalWrite(gpio1, HIGH);
} else {
digitalWrite(gpio1, LOW);
}
if (radio2Button.isPressed()) {
digitalWrite(gpio2, HIGH);
} else {
digitalWrite(gpio2, LOW);
}
}
```
Step 4: Amplifying the Audio Signal
---------------------------------
To amplify the audio signal, I used a 20W ClassD amplifier board. The amplifier board takes the digital audio signal from the ESP32 microcontroller and amplifies it to a higher level.
```c
// Initialize amplifier board
const int amplifierPin = 12;
void setup() {
// Initialize amplifier pin as output
pinMode(amplifierPin, OUTPUT);
}
void loop() {
// Read input from I2S pins
int i2s1 = analogRead(0); // replace with your I2S pin
int i2s2 = analogRead(1); // replace with your I2S pin
// Amplify audio signal using amplifier board
analogWrite(amplifierPin, map(i2s1, 0, 1023, 0, 255));
}
```
Conclusion
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In this project, we created a custom radio controller that can switch between five different German stations using an ESP32 microcontroller and a touchscreen interface. We also amplified the audio signal using a ClassD amplifier board. With this project, you can create your own radio controller with a user-friendly interface and advanced features like amplifying the audio signal.