Low-Cost Pest-Detecting Car

#include <Arduino.h>
#include <Wire.h>
#include <WiFi.h>
#include <WebServer.h>
#include "esp_camera.h"

const char *AP_NAME = "Carro-Plagas";
const char *AP_PASSWORD = "plagas123";

#define IR_SENSOR_PIN 3
#define I2C_SDA_PIN 13
#define I2C_SCL_PIN 14
#define FLASH_LED_PIN 4
const uint8_t PCF8574_ADDRESS = 0x20;
const unsigned long MAX_DRIVE_MS = 20000;

#define PWDN_GPIO_NUM 32
#define RESET_GPIO_NUM -1
#define XCLK_GPIO_NUM 0
#define SIOD_GPIO_NUM 26
#define SIOC_GPIO_NUM 27
#define Y9_GPIO_NUM 35
#define Y8_GPIO_NUM 34
#define Y7_GPIO_NUM 39
#define Y6_GPIO_NUM 36
#define Y5_GPIO_NUM 21
#define Y4_GPIO_NUM 19
#define Y3_GPIO_NUM 18
#define Y2_GPIO_NUM 5
#define VSYNC_GPIO_NUM 25
#define HREF_GPIO_NUM 23
#define PCLK_GPIO_NUM 22

WebServer server(80);
bool activitySeen = false, flashOn = false, driving = false;
int lastSensorState = HIGH;
unsigned long lastChangeMs = 0, driveStartedMs = 0;

void writeMotorByte(uint8_t value) { Wire.beginTransmission(PCF8574_ADDRESS); Wire.write(value); Wire.endTransmission(); }
void stopCar() { writeMotorByte(0x00); driving = false; }
void driveForward() { writeMotorByte(0x05); driving = true; driveStartedMs = millis(); }
void setFlash(bool on) { flashOn = on; digitalWrite(FLASH_LED_PIN, on ? HIGH : LOW); }

void sendHome() {
  String page = R"HTML(<!doctype html><html lang="es"><head><meta name="viewport" content="width=device-width,initial-scale=1"><title>Carro detector de plagas</title><style>body{font-family:Arial;margin:22px;background:#f4f7ed;color:#20331c}button{font-size:17px;padding:12px;margin:4px;border-radius:8px;border:0;background:#5b842f;color:white}.stop{background:#a33}img{max-width:100%;border-radius:8px;border:3px solid #5b842f}</style></head><body><h1>Carro detector de plagas</h1><p id="state">Leyendo...</p><button onclick="go()">Iniciar recorrido</button><button class="stop" onclick="stop()">Detener carro</button><button onclick="foto()">Tomar foto</button><button onclick="flash()">Encender/apagar luz</button><p><img id="photo" alt="La foto aparecerá aquí"></p><p>El carro se detiene si el sensor nota algo muy cerca. Revisa la foto: el sensor no identifica especies por sí solo.</p><script>async function estado(){let r=await fetch('/status');let j=await r.json();document.getElementById('state').textContent=j.driving?'El carro avanza despacio':(j.activity?'Actividad detectada: carro detenido':'Carro detenido, listo');}async function go(){await fetch('/go');estado();}async function stop(){await fetch('/stop');estado();}function foto(){document.getElementById('photo').src='/capture?t='+Date.now();}async function flash(){await fetch('/flash');}setInterval(estado,700);estado();</script></body></html>)HTML";
  server.send(200, "text/html; charset=utf-8", page);
}
void sendStatus() { String json = String("{\"activity\":") + (activitySeen ? "true" : "false") + ",\"driving\":" + (driving ? "true" : "false") + "}"; server.send(200, "application/json", json); }
void capturePhoto() { camera_fb_t *frame = esp_camera_fb_get(); if (!frame) { server.send(503, "text/plain", "La camara no pudo tomar una foto"); return; } server.sendHeader("Content-Disposition", "inline; filename=foto.jpg"); server.setContentLength(frame->len); server.send(200, "image/jpeg", ""); server.client().write(frame->buf, frame->len); esp_camera_fb_return(frame); }

bool startCamera() {
  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.pixel_format=PIXFORMAT_JPEG; config.frame_size=FRAMESIZE_VGA; config.jpeg_quality=12; config.fb_count=psramFound()?2:1; return esp_camera_init(&config)==ESP_OK;
}

void setup() {
  pinMode(IR_SENSOR_PIN, INPUT); pinMode(FLASH_LED_PIN, OUTPUT); setFlash(false);
  Wire.begin(I2C_SDA_PIN, I2C_SCL_PIN); stopCar();
  if (!startCamera()) return;
  WiFi.mode(WIFI_AP); WiFi.softAP(AP_NAME, AP_PASSWORD);
  server.on("/", HTTP_GET, sendHome); server.on("/status", HTTP_GET, sendStatus); server.on("/capture", HTTP_GET, capturePhoto);
  server.on("/go", HTTP_GET, [](){ activitySeen=false; driveForward(); server.send(200,"text/plain","Recorrido iniciado"); });
  server.on("/stop", HTTP_GET, [](){ stopCar(); server.send(200,"text/plain","Carro detenido"); });
  server.on("/flash", HTTP_GET, [](){ setFlash(!flashOn); server.send(200,"text/plain",flashOn?"Luz encendida":"Luz apagada"); });
  server.begin();
}
void loop() {
  server.handleClient(); int sensorState=digitalRead(IR_SENSOR_PIN);
  if (sensorState!=lastSensorState && millis()-lastChangeMs>80) { lastChangeMs=millis(); lastSensorState=sensorState; if (sensorState==LOW && driving) { activitySeen=true; stopCar(); } }
  if (driving && millis()-driveStartedMs>=MAX_DRIVE_MS) stopCar();
}