// Autonomous RC Car — ExoSynk flagship demo // // Layers: // 1. Obstacle avoidance via HC-SR04 (pulseIn on D3, trigger on D2) // 2. Tilt / crash detection via MPU6050 over I²C (addr 0x68) // 3. Status: NeoPixel strip on D12 (headlights + brake lights) // OLED on I²C (addr 0x3C) shows mode + distance // tone() on D8 for horn / alert beeps // 4. Remote override via HC-05 BT — press S to halt, F to force forward // // Watch the car drive on the World · RC panel (auto-opens when L298N is placed). const ENA = 5, IN1 = 6, IN2 = 7; // left motor const ENB = 9, IN3 = 10, IN4 = 11; // right motor const TRIG = 2, ECHO = 3; const HORN = 8, STRIP = 12; const MPU = 0x68, OLED = 0x3c; let mode = "ROAM"; // ROAM | STOP | OVERRIDE let lastStatusMs = 0; function drive(L, R) { digitalWrite(IN1, L > 0 ? HIGH : LOW); digitalWrite(IN2, L < 0 ? HIGH : LOW); analogWrite(ENA, Math.min(255, Math.abs(L))); digitalWrite(IN3, R > 0 ? HIGH : LOW); digitalWrite(IN4, R < 0 ? HIGH : LOW); analogWrite(ENB, Math.min(255, Math.abs(R))); } function stop() { drive(0, 0); } function lamp(r, g, b) { for (let i = 0; i < 8; i++) neoPixel.setPixel(STRIP, i, r, g, b); neoPixel.show(STRIP); } function distanceCm() { digitalWrite(TRIG, LOW); for (let i = 0; i < 400; i++) {} // tight settle digitalWrite(TRIG, HIGH); for (let i = 0; i < 800; i++) {} digitalWrite(TRIG, LOW); const us = pulseIn(ECHO, HIGH, 30000); return us / 58; } function readAccelX() { Wire.beginTransmission(MPU); Wire.write(0x3b); // ACCEL_XOUT_H Wire.endTransmission(); Wire.requestFrom(MPU, 2); const hi = Wire.read(), lo = Wire.read(); let raw = (hi << 8) | lo; if (raw & 0x8000) raw -= 0x10000; // sign-extend to int16 return raw / 16384; // g } function oledPrint(msg) { Wire.beginTransmission(OLED); Wire.write(0x40); // data stream for (let i = 0; i < msg.length; i++) Wire.write(msg.charCodeAt(i)); Wire.endTransmission(); } function setup() { for (const p of [ENA, IN1, IN2, ENB, IN3, IN4, TRIG, HORN]) pinMode(p, OUTPUT); pinMode(ECHO, INPUT); Wire.begin(); Serial.begin(9600); Serial.println("ExoSynk RC Car online."); lamp(0, 64, 255); oledPrint("ExoSynk RC"); tone(HORN, 660, 120); } async function loop() { // --- 1. BT remote override ------------------------------------------------- while (BT.available()) { const c = String.fromCharCode(BT.read()); if (c === 'S') { mode = "OVERRIDE"; stop(); lamp(255, 0, 0); tone(HORN, 440, 200); BT.println("HALTED"); } if (c === 'F') { mode = "OVERRIDE"; drive(220, 220); lamp(255, 255, 255); BT.println("FWD"); } if (c === 'L') { mode = "OVERRIDE"; drive(-150, 200); lamp(255, 200, 0); } if (c === 'R') { mode = "OVERRIDE"; drive(200, -150); lamp(255, 200, 0); } if (c === 'A') { mode = "ROAM"; BT.println("AUTO"); } } // --- 2. Crash / tilt detect ----------------------------------------------- const ax = readAccelX(); if (Math.abs(ax) > 0.6 && mode !== "OVERRIDE") { mode = "STOP"; stop(); lamp(255, 96, 0); tone(HORN, 300, 400); Serial.print("TILT "); Serial.println(ax); await delay(300); mode = "ROAM"; } // --- 3. Autonomous roam ---------------------------------------------------- if (mode === "ROAM") { const cm = distanceCm(); if (cm < 12) { // Obstacle — back-up-and-turn lamp(255, 0, 0); drive(-180, -180); await delay(250); drive(180, -180); await delay(350); } else if (cm < 30) { lamp(255, 200, 0); drive(120, 120); } else { lamp(0, 200, 80); drive(200, 200); } if (millis() - lastStatusMs > 500) { oledPrint(`${Math.round(cm)}cm `); lastStatusMs = millis(); } } await delay(40); }