Role
Design & Engineering Lead
Timeline
September 2026
Stack Tags
ESP32
Embedded systems
Firmware
Overview & Problem Statement
BluePad32 turns the ESP32 into a Bluetooth host that can pair directly with a PS4, PS5, Xbox, or Switch controller; no separate Bluetooth module is needed, since it uses the ESP32's built-in radio. To pair a PS4 controller specifically, hold the Share and PS buttons together until the light bar flashes rapidly.
System Architecture & Technical Approach
Pairing accommodates rumble feedback on every button press and logging that tracks how many times each button has been pressed.
Hardware & Software Implementation
// ESP32 + PS4 Controller via Bluepad32 — pairing, button reading,
// vibration feedback, and click logging
#include <Bluepad32.h>
// Button bitmasks (Bluepad32's PS4 mapping)
#define BUTTON_CROSS 0x0001
#define BUTTON_CIRCLE 0x0002
#define BUTTON_SQUARE 0x0004
#define BUTTON_TRIANGLE 0x0008
#define BUTTON_L1 0x0010
#define BUTTON_R1 0x0020
#define BUTTON_L3 0x0040
#define BUTTON_R3 0x0080
#define ANALOG_DEADZONE 30 // ignore small stick drift near center
GamepadPtr myGamepad = nullptr;
bool controllerConnected = false;
// One struct per tracked button — bundles its bitmask, a human-readable
// name for logging, its previous pressed/released state, a running click
// count, and the timestamp of its last press.
struct ButtonTracker {
uint32_t mask;
const char* name;
bool wasPressed;
unsigned long pressCount;
unsigned long lastPressTime;
};
ButtonTracker buttons[] = {
{ BUTTON_CROSS, "Cross", false, 0, 0 },
{ BUTTON_CIRCLE, "Circle", false, 0, 0 },
{ BUTTON_SQUARE, "Square", false, 0, 0 },
{ BUTTON_TRIANGLE, "Triangle", false, 0, 0 },
{ BUTTON_L1, "L1", false, 0, 0 },
{ BUTTON_R1, "R1", false, 0, 0 },
{ BUTTON_L3, "L3", false, 0, 0 },
{ BUTTON_R3, "R3", false, 0, 0 },
};
const int NUM_BUTTONS = sizeof(buttons) / sizeof(buttons[0]);
void onConnectedGamepad(GamepadPtr gp) {
if (myGamepad == nullptr) {
Serial.println("PS4 controller connected!");
myGamepad = gp;
controllerConnected = true;
gp->setColorLED(0, 255, 0);
vibrate(0x80, 0x40, 200); // confirmation buzz on connect
}
}
void onDisconnectedGamepad(GamepadPtr gp) {
if (myGamepad == gp) {
Serial.println("PS4 controller disconnected.");
myGamepad = nullptr;
controllerConnected = false;
}
}
// Centralized vibration helper — every button handler calls this instead
// of repeating the rumble-then-delay-then-stop pattern inline
void vibrate(uint8_t strongMotor, uint8_t weakMotor, int durationMs) {
if (!myGamepad) return;
myGamepad->setRumble(strongMotor, weakMotor);
delay(durationMs);
myGamepad->setRumble(0, 0);
}
void setup() {
Serial.begin(115200);
delay(2000);
Serial.println("Initializing Bluepad32...");
BP32.setup(&onConnectedGamepad, &onDisconnectedGamepad);
BP32.forgetBluetoothKeys();
Serial.println("Hold SHARE + PS until the light bar flashes rapidly to pair.");
Serial.println("Button | Press Count | Time Since Boot (ms)");
}
void loop() {
bool dataUpdated = BP32.update();
if (dataUpdated && controllerConnected && myGamepad != nullptr) {
processButtons();
}
delay(1);
}
void processButtons() {
uint32_t currentState = myGamepad->buttons();
for (int i = 0; i < NUM_BUTTONS; i++) {
bool isPressed = currentState & buttons[i].mask;
// Rising edge — button just went from not-pressed to pressed
if (isPressed && !buttons[i].wasPressed) {
buttons[i].wasPressed = true;
buttons[i].pressCount++;
buttons[i].lastPressTime = millis();
logButtonPress(buttons[i]);
vibrate(0x80, 0x40, 100); // every press gets a short buzz
}
// Falling edge — button released, reset for next press
else if (!isPressed && buttons[i].wasPressed) {
buttons[i].wasPressed = false;
}
}
}
void logButtonPress(const ButtonTracker &btn) {
Serial.print(btn.name);
Serial.print(" | Press #");
Serial.print(btn.pressCount);
Serial.print(" | t=");
Serial.print(btn.lastPressTime);
Serial.println("ms");
}Key Challenges & Technical Trade-offs
Logging every press to Serial with delay(100) for the vibration inside the same loop iteration briefly blocks other button reads, for a build with many simultaneous button presses expected, this would need to move to a non-blocking timer instead of a delay()
Results, Impact & Performance Metrics
Every tracked button now vibrates on press and logs its name, running press count, and timestamp to Serial.