DIY SPY CAR

🕵️‍♂️ DIY SPY CAR · XIAO ESP32-S3 SENSE

⚡ 4WD | FPV Live-Stream | Tactical UI | Night Ops LED | WebSocket Control

🔎 What is SPY CAR?

A compact 4WD reconnaissance robot built around the XIAO ESP32-S3 Sense. Streams live video to any smartphone, features tactical white LEDs, 4 individually controlled N20 motors, real‑time CPU temperature and a military‑style web dashboard. Perfect for FPV exploration, spy‑themed projects or RC fun.

⚙️ How It Works

• XIAO ESP32-S3 Sense captures QVGA video (JPEG) → streamed via HTTP.
• Two DRV8833 dual H‑bridge drivers control 4 N20 motors (tank steering).
• MT3608 boost converter lifts 3.7V LiPo → stable 5V for ESP32 and camera.
• WebSocket server handles real‑time commands (forward/back/pivot/stop) with ultra-low latency.
• Tactical LED bar (4x white LEDs) activated from dashboard.
• Integrated temperature sensor sends core readings to web UI.

📦 Components Required

• XIAO ESP32-S3 Sense – Buy Here
• N20 Motors (4x) – Buy Here
• TP4056 Charging Module – Buy Here
• 3.7V LiPo Battery 1000mAh – Buy Here
• 4mm Slide Switch – Buy Here
• Jumper Wires – Buy Here
• DRV8833 Motor Driver (2x) – Buy Here
• MT3608 Booster Module – Buy Here
• 8mm White LEDs (4x) – Buy Here
• 220 Ohm Resistors (4x) – Buy Here

🖨️ 3D Print Files + Materials

📁 Download STL files (chassis, wheels, top cover, camera mount):

Recommended filaments:
🧱 Base + Top → 3201PA - F Nylone
🛞 Wheels → 1172Pro Nylone
⚫ Tyres → TPU
🔧 Print with 0.2mm layer, 40% infill.

🚀 Order 3D prints from JLC3DP

🔌 Pin Connections (XIAO ESP32-S3 Sense)

Component	XIAO Pin	Notes
DRV8833 #1 (Left motors)	D0, D1, D2, D3	IN1/IN2 – Motor A ; IN3/IN4 – Motor B
DRV8833 #2 (Right motors)	D4, D5, D6, D7	corresponding control pins
LED Bar (4x white) via 220Ω	D8	Active HIGH (tactical light)
MT3608 Boost (5V out)	5V / GND	powers ESP32 & camera
TP4056 + Battery	OUT+ → MT3608 IN+	3.7V LiPo → boost converter

⚡ Important: Adjust MT3608 to 5.0V before connecting to XIAO. Use a slide switch between battery + and TP4056 input for safety.

⚡ Features & Performance

📹 FPV Live Video (QVGA 320x240) / low latency

🎮 WebSocket commands → instant movement

🌡️ Real‑time Core temperature + uptime

💡 Tactical LED Bar (night mode)

🔋 1000mAh LiPo → 45+ min runtime

⚙️ Tank steering & 4WD traction

---

💻 Arduino Firmware (Full Code)

/*
  By SIMPLE CIRCUITS
  SPY CAR - XIAO ESP32-S3 Sense with DRV8833 Dual Motor Drivers
  - 4 N20 motors individually controlled
  - Military Themed Web Interface
  - LED control on D8
  - Internal temperature monitoring
*/

#include <WiFi.h>
#include <WebServer.h>
#include <WebSocketsServer.h>
#include <esp_camera.h>
#include <Arduino.h>

// ==================== WiFi Credentials ====================
const char* ssid = "SPY_CAR_HOTSPOT";
const char* password = "spycar1234";

// ==================== Pin Definitions ====================
#define LEFT_IN1    D0
#define LEFT_IN2    D1
#define LEFT_IN3    D2
#define LEFT_IN4    D3

#define RIGHT_IN1   D4
#define RIGHT_IN2   D5
#define RIGHT_IN3   D6
#define RIGHT_IN4   D7

#define LED_PIN     D8

// ==================== Camera Pin Definitions ====================
#define PWDN_GPIO_NUM     -1
#define RESET_GPIO_NUM    -1
#define XCLK_GPIO_NUM      10
#define SIOD_GPIO_NUM      40
#define SIOC_GPIO_NUM      39
#define Y9_GPIO_NUM        48
#define Y8_GPIO_NUM        11
#define Y7_GPIO_NUM        12
#define Y6_GPIO_NUM        14
#define Y5_GPIO_NUM        16
#define Y4_GPIO_NUM        18
#define Y3_GPIO_NUM        17
#define Y2_GPIO_NUM        15
#define VSYNC_GPIO_NUM     38
#define HREF_GPIO_NUM      47
#define PCLK_GPIO_NUM      13

// ==================== Global Variables ====================
WebServer server(80);
WebSocketsServer webSocket = WebSocketsServer(81);
bool ledState = false;
float cpuTemp = 0;

// ==================== Motor Control Functions ====================
#define MOTOR_FORWARD   HIGH
#define MOTOR_BACKWARD  LOW

void setMotorPins(int in1, int in2, bool forward) {
  if (forward) {
    digitalWrite(in1, MOTOR_FORWARD);
    digitalWrite(in2, MOTOR_BACKWARD);
  } else {
    digitalWrite(in1, MOTOR_BACKWARD);
    digitalWrite(in2, MOTOR_FORWARD);
  }
}

void stopMotorPins(int in1, int in2) {
  digitalWrite(in1, LOW);
  digitalWrite(in2, LOW);
}

void moveForward() {
  setMotorPins(LEFT_IN1, LEFT_IN2, true);
  setMotorPins(LEFT_IN3, LEFT_IN4, true);
  setMotorPins(RIGHT_IN1, RIGHT_IN2, true);
  setMotorPins(RIGHT_IN3, RIGHT_IN4, true);
}

void moveBackward() {
  setMotorPins(LEFT_IN1, LEFT_IN2, false);
  setMotorPins(LEFT_IN3, LEFT_IN4, false);
  setMotorPins(RIGHT_IN1, RIGHT_IN2, false);
  setMotorPins(RIGHT_IN3, RIGHT_IN4, false);
}

void rotateLeft() {
  setMotorPins(LEFT_IN1, LEFT_IN2, false);
  setMotorPins(LEFT_IN3, LEFT_IN4, false);
  setMotorPins(RIGHT_IN1, RIGHT_IN2, true);
  setMotorPins(RIGHT_IN3, RIGHT_IN4, true);
}

void rotateRight() {
  setMotorPins(LEFT_IN1, LEFT_IN2, true);
  setMotorPins(LEFT_IN3, LEFT_IN4, true);
  setMotorPins(RIGHT_IN1, RIGHT_IN2, false);
  setMotorPins(RIGHT_IN3, RIGHT_IN4, false);
}

void stopAllMotors() {
  stopMotorPins(LEFT_IN1, LEFT_IN2);
  stopMotorPins(LEFT_IN3, LEFT_IN4);
  stopMotorPins(RIGHT_IN1, RIGHT_IN2);
  stopMotorPins(RIGHT_IN3, RIGHT_IN4);
}

void toggleLED() {
  ledState = !ledState;
  digitalWrite(LED_PIN, ledState ? HIGH : LOW);
}

void readTemperature() {
  cpuTemp = temperatureRead();
}

// ==================== Camera Initialization ====================
void initCamera() {
  camera_config_t config;
  config.ledc_channel = LEDC_CHANNEL_0;
  config.ledc_timer = LEDC_TIMER_0;
  config.pin_d0 = Y2_GPIO_NUM;
  config.pin_d1 = Y3_GPIO_NUM;
  config.pin_d2 = Y4_GPIO_NUM;
  config.pin_d3 = Y5_GPIO_NUM;
  config.pin_d4 = Y6_GPIO_NUM;
  config.pin_d5 = Y7_GPIO_NUM;
  config.pin_d6 = Y8_GPIO_NUM;
  config.pin_d7 = Y9_GPIO_NUM;
  config.pin_xclk = XCLK_GPIO_NUM;
  config.pin_pclk = PCLK_GPIO_NUM;
  config.pin_vsync = VSYNC_GPIO_NUM;
  config.pin_href = HREF_GPIO_NUM;
  config.pin_sscb_sda = SIOD_GPIO_NUM;
  config.pin_sscb_scl = SIOC_GPIO_NUM;
  config.pin_pwdn = PWDN_GPIO_NUM;
  config.pin_reset = RESET_GPIO_NUM;
  config.xclk_freq_hz = 20000000;
  config.frame_size = FRAMESIZE_QVGA;
  config.pixel_format = PIXFORMAT_JPEG;
  config.grab_mode = CAMERA_GRAB_WHEN_EMPTY;
  config.fb_location = CAMERA_FB_IN_PSRAM;
  config.jpeg_quality = 12;
  config.fb_count = 1;

  esp_err_t err = esp_camera_init(&config);
  if (err != ESP_OK) {
    Serial.printf("Camera init failed with error 0x%x\n", err);
    return;
  }
  
  sensor_t * s = esp_camera_sensor_get();
  if (s) {
    s->set_vflip(s, 1);
    s->set_hmirror(s, 1);
  }
}

// ==================== Web Interface HTML ====================
const char index_html[] PROGMEM = R"rawliteral(
<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no, viewport-fit=cover">
    <title>SPY CAR CONTROLLER</title>
    <style>
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        body {
            background: #0d1117;
            font-family: monospace;
            padding: 20px;
        }
        .container {
            max-width: 500px;
            margin: auto;
            background: #161b22;
            border-radius: 16px;
            padding: 20px;
        }
        button {
            background: #238636;
            color: white;
            border: none;
            padding: 10px 20px;
            margin: 5px;
            border-radius: 8px;
            cursor: pointer;
        }
        .cam {
            background: black;
            text-align: center;
            padding: 10px;
            margin-bottom: 10px;
        }
        img { width: 100%; }
        .info { margin-top: 10px; font-size: 12px; }
    </style>
</head>
<body>
<div class="container">
    <h3>SPY CAR CONTROL</h3>
    <div class="cam"><img id="camera-feed" src="/stream"></div>
    <button id="ledBtn">💡 LED TOGGLE</button>
    <div>
        <button id="fwd">▲ FORWARD</button>
        <button id="rev">▼ BACKWARD</button>
        <button id="left">◀ LEFT</button>
        <button id="right">▶ RIGHT</button>
        <button id="stop">⏹ STOP</button>
    </div>
    <div class="info">Temp: <span id="temp">--</span>°C | Uptime: <span id="uptime">0</span>s</div>
</div>
<script>
let ws;
function connect() {
    ws = new WebSocket(`ws://${location.hostname}:81`);
    ws.onmessage = e => { if(e.data.startsWith('temp:')) document.getElementById('temp').innerText = parseFloat(e.data.split(':')[1]).toFixed(1); };
}
function send(c) { if(ws && ws.readyState === WebSocket.OPEN) ws.send(c+':1'); }
document.getElementById('fwd').onmousedown = () => send('forward');
document.getElementById('fwd').onmouseup = () => send('stop');
document.getElementById('rev').onmousedown = () => send('backward');
document.getElementById('rev').onmouseup = () => send('stop');
document.getElementById('left').onmousedown = () => send('left');
document.getElementById('left').onmouseup = () => send('stop');
document.getElementById('right').onmousedown = () => send('right');
document.getElementById('right').onmouseup = () => send('stop');
document.getElementById('stop').onclick = () => send('stop');
let led = false;
document.getElementById('ledBtn').onclick = () => { led = !led; send('led:' + (led?1:0)); };
setInterval(() => { let img = document.getElementById('camera-feed'); img.src = '/stream?_=' + Date.now(); }, 100);
let start = Date.now();
setInterval(() => { document.getElementById('uptime').innerText = Math.floor((Date.now()-start)/1000); }, 1000);
connect();
</script>
</body>
</html>
)rawliteral";

// ==================== WebSocket Event Handler ====================
void webSocketEvent(uint8_t num, WStype_t type, uint8_t *payload, size_t length) {
  if (type == WStype_TEXT) {
    String command = String((char*)payload);
    int sep = command.indexOf(':');
    if (sep > 0) {
      String cmd = command.substring(0, sep);
      String val = command.substring(sep + 1);
      
      if (cmd == "forward") {
        rotateRight();
      } 
      else if (cmd == "backward") {
        rotateLeft();
      }
      else if (cmd == "left") {
        moveBackward();
      }
      else if (cmd == "right") {
        moveForward();
      }
      else if (cmd == "stop") {
        stopAllMotors();
      }
      else if (cmd == "led") {
        if (val == "1" && !ledState) toggleLED();
        else if (val == "0" && ledState) toggleLED();
      }
    }
  }
}

// ==================== HTTP Request Handlers ====================
void handleRoot() {
  server.send(200, "text/html", index_html);
}

void handleStream() {
  camera_fb_t *fb = esp_camera_fb_get();
  if (!fb) {
    server.send(500, "text/plain", "Camera capture failed");
    return;
  }
  server.sendHeader("Content-Type", "image/jpeg");
  server.sendHeader("Content-Length", String(fb->len));
  server.send_P(200, "image/jpeg", (const char*)fb->buf, fb->len);
  esp_camera_fb_return(fb);
}

void handleNotFound() {
  server.send(404, "text/plain", "Not Found");
}

// ==================== Setup ====================
void setup() {
  Serial.begin(115200);
  Serial.println("\n=== SPY CAR CONTROLLER ===");
  
  pinMode(LEFT_IN1, OUTPUT);
  pinMode(LEFT_IN2, OUTPUT);
  pinMode(LEFT_IN3, OUTPUT);
  pinMode(LEFT_IN4, OUTPUT);
  pinMode(RIGHT_IN1, OUTPUT);
  pinMode(RIGHT_IN2, OUTPUT);
  pinMode(RIGHT_IN3, OUTPUT);
  pinMode(RIGHT_IN4, OUTPUT);
  pinMode(LED_PIN, OUTPUT);
  
  stopAllMotors();
  digitalWrite(LED_PIN, LOW);
  
  initCamera();
  
  Serial.println("Connecting to WiFi...");
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  
  int attempts = 0;
  while (WiFi.status() != WL_CONNECTED && attempts < 30) {
    delay(500);
    attempts++;
  }
  
  IPAddress myIP;
  
  if (WiFi.status() == WL_CONNECTED) {
    myIP = WiFi.localIP();
    Serial.println("WiFi Connected!");
  } else {
    WiFi.mode(WIFI_AP);
    WiFi.softAP(ssid, password);
    myIP = WiFi.softAPIP();
    Serial.println("AP Mode Active");
  }
  
  server.on("/", handleRoot);
  server.on("/stream", handleStream);
  server.onNotFound(handleNotFound);
  server.begin();
  
  webSocket.begin();
  webSocket.onEvent(webSocketEvent);
  
  Serial.print("IP: ");
  Serial.println(myIP);
  Serial.println("SPY CAR CONTROLLER READY");
}

void loop() {
  server.handleClient();
  webSocket.loop();
  
  static unsigned long lastTempUpdate = 0;
  if (millis() - lastTempUpdate > 2000) {
    readTemperature();
    String tempMsg = "temp:" + String(cpuTemp, 1);
    webSocket.broadcastTXT(tempMsg);
    lastTempUpdate = millis();
  }
  
  delay(1);
}

📡 Code highlights: creates WiFi AP "SPY_CAR_HOTSPOT" (pw: spycar1234), serves real‑time dashboard, WebSocket low‑latency driving, camera stream at QVGA, automatic temperature broadcast.

🛠️ Assembly (6 steps)

• 1️⃣ 3D print all parts (Nylon base + TPU tyres).
• 2️⃣ Solder DRV8833 modules, connect motors to outputs and XIAO pins D0-D7.
• 3️⃣ Set MT3608 to 5.0V, connect to 5V/GND of XIAO.
• 4️⃣ Wire slide switch, TP4056, battery and boost converter.
• 5️⃣ LED bar: 4x white LEDs + 220Ω resistors to D8 and GND.
• 6️⃣ Upload sketch, power ON, connect phone to SPY_CAR_HOTSPOT. Open browser → 192.168.4.1

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🔍 Tip: For better night vision, add IR LEDs (940nm) parallel to white LEDs. Adjust camera quality (jpeg_quality) for smoother FPS.