tyler parker
bb1d70c620
Self-contained project code for the "Godot Isn't Just for Games" series: Arduino sketches, the Python serial<->UDP bridge, and the Godot 4 projects, one folder per article.
80 lines
2.5 KiB
Arduino
80 lines
2.5 KiB
Arduino
/*
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* JoystickBridge.ino — Arduino Uno <-> Godot (ArduinoGodot/Main.gd)
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*
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* Talks plain serial lines to the UDP<->serial bridge process, which forwards
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* telemetry to Godot on UDP 4242 and relays LED commands from UDP 4243.
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*
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* PROTOCOL (must match Main.gd)
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* OUT (Uno -> host): "x,y,btn\n" raw 10-bit ADC, e.g. "512,498,1"
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* btn = 1 when the stick's push-button is pressed.
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* IN (host -> Uno): "L1" = LED on, "L0" = LED off (newline optional)
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*
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* WIRING (KY-023 2-axis analog joystick + external LED)
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* Joystick +5V / VCC -> 5V
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* Joystick GND -> GND
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* Joystick VRx -> A0
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* Joystick VRy -> A1
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* Joystick SW -> D2 (uses internal pull-up; pressed = LOW)
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*
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* LED: D13 -> 220 ohm resistor -> LED anode (+, long leg)
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* LED cathode (-, short leg) -> GND
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* (D13 is also the Uno's onboard LED, so it flashes during every upload —
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* a free "is this pin alive" check. 220-330 ohm keeps it near ~15 mA.)
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*/
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const uint8_t PIN_VRX = A0; // joystick X axis
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const uint8_t PIN_VRY = A1; // joystick Y axis
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const uint8_t PIN_SW = 2; // joystick push-button (active LOW)
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const uint8_t PIN_LED = 13; // external LED through a 220 ohm resistor (also onboard LED)
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const unsigned long BAUD = 115200; // must match the bridge process
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const unsigned long SEND_MS = 16; // ~60 Hz telemetry
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unsigned long lastSend = 0;
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char cmdBuf[8];
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uint8_t cmdLen = 0;
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void setup() {
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Serial.begin(BAUD);
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pinMode(PIN_SW, INPUT_PULLUP);
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pinMode(PIN_LED, OUTPUT);
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digitalWrite(PIN_LED, LOW);
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}
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void loop() {
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handleCommands();
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unsigned long now = millis();
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if (now - lastSend >= SEND_MS) {
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lastSend = now;
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int x = analogRead(PIN_VRX); // 0..1023
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int y = analogRead(PIN_VRY); // 0..1023
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int btn = (digitalRead(PIN_SW) == LOW) // pull-up: LOW == pressed
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? 1 : 0; // Godot wants 1 = pressed
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// "x,y,btn\n"
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Serial.print(x);
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Serial.print(',');
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Serial.print(y);
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Serial.print(',');
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Serial.println(btn);
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}
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}
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// Parse newline-terminated commands. Recognizes "L1" / "L0".
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void handleCommands() {
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while (Serial.available() > 0) {
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char c = Serial.read();
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if (c == '\n' || c == '\r') {
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if (cmdLen >= 2 && cmdBuf[0] == 'L') {
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digitalWrite(PIN_LED, cmdBuf[1] == '1' ? HIGH : LOW);
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}
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cmdLen = 0;
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} else if (cmdLen < sizeof(cmdBuf) - 1) {
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cmdBuf[cmdLen++] = c;
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} else {
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cmdLen = 0; // overflow guard: drop the runt line
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}
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}
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}
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