Solar Panel Tracking Cleaner

#include <Wire.h>
#include <Adafruit_INA219.h>
#include <Adafruit_BME280.h>
#include <soc/gpio_struct.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <ESP32Servo.h>

#define DS18B20_PIN 4
#define AZIMUTH_SERVO_PIN 25
#define ELEVATION_SERVO_PIN 26
#define TB_AIN1_PIN 16
#define TB_AIN2_PIN 17
#define TB_PWMA_PIN 18
#define TB_STBY_PIN 19
#define CLEANER_HOME_PIN 32
#define CLEANER_FAR_PIN 33
#define LDR_NW_PIN 36
#define LDR_NE_PIN 39
#define LDR_SW_PIN 34
#define LDR_SE_PIN 35
#define DUST_PIN 27

const int SERVO_MIN_DEG = 15;
const int SERVO_MAX_DEG = 165;
const int TRACK_DEADBAND = 120;
const int DUST_CLEAN_THRESHOLD = 2500;
const uint32_t SENSOR_PERIOD_MS = 2000;
const uint32_t CLEAN_TIMEOUT_MS = 30000;

Adafruit_INA219 ina219;
Adafruit_BME280 bme;
OneWire oneWire(DS18B20_PIN);
DallasTemperature panelTemperature(&oneWire);
Servo azimuthServo;
Servo elevationServo;

int azimuthDeg = 90;
int elevationDeg = 90;
uint32_t lastSampleMs = 0;
uint32_t cleanerStartMs = 0;
bool cleanerRunning = false;
bool cleanerReturning = false;

int readAverage(int pin) {
  uint32_t sum = 0;
  for (int i = 0; i < 8; ++i) {
    sum += analogRead(pin);
    delay(2);
  }
  return sum / 8;
}

void stopCleaner() {
  ledcWrite(TB_PWMA_PIN, 0);
  digitalWrite(TB_AIN1_PIN, LOW);
  digitalWrite(TB_AIN2_PIN, LOW);
  cleanerRunning = false;
  cleanerReturning = false;
}

void runCleanerTowardFarEnd() {
  digitalWrite(TB_STBY_PIN, HIGH);
  digitalWrite(TB_AIN1_PIN, HIGH);
  digitalWrite(TB_AIN2_PIN, LOW);
  ledcWrite(TB_PWMA_PIN, 180);
  cleanerStartMs = millis();
  cleanerRunning = true;
  cleanerReturning = false;
}

void returnCleanerHome() {
  digitalWrite(TB_AIN1_PIN, LOW);
  digitalWrite(TB_AIN2_PIN, HIGH);
  ledcWrite(TB_PWMA_PIN, 180);
  cleanerStartMs = millis();
  cleanerRunning = true;
  cleanerReturning = true;
}

void updateTracker(int nw, int ne, int sw, int se) {
  int left = nw + sw;
  int right = ne + se;
  int top = nw + ne;
  int bottom = sw + se;

  if (abs(left - right) > TRACK_DEADBAND) azimuthDeg += (right > left) ? 1 : -1;
  if (abs(top - bottom) > TRACK_DEADBAND) elevationDeg += (top > bottom) ? 1 : -1;
  azimuthDeg = constrain(azimuthDeg, SERVO_MIN_DEG, SERVO_MAX_DEG);
  elevationDeg = constrain(elevationDeg, SERVO_MIN_DEG, SERVO_MAX_DEG);
  azimuthServo.write(azimuthDeg);
  elevationServo.write(elevationDeg);
}

void reportMaintenance(int ldrMean, int dust, float busVoltage, float currentmA, float panelC, float airC, float humidity) {
  bool lowSolarOutput = ldrMean > 1800 && busVoltage < 4.0F;
  bool dirtyPanel = dust > DUST_CLEAN_THRESHOLD;
  bool hotPanel = panelC > 75.0F;
  Serial.printf("LDR=%d dust=%d PV=%.2fV %.0fmA panel=%.1fC air=%.1fC RH=%.1f%%\n", ldrMean, dust, busVoltage, currentmA, panelC, airC, humidity);
  if (lowSolarOutput) Serial.println("MAINTENANCE: panel voltage is low despite bright light; inspect panel, wiring, and charger/load.");
  if (dirtyPanel) Serial.println("MAINTENANCE: dust input exceeds the cleaning threshold.");
  if (hotPanel) Serial.println("MAINTENANCE: panel temperature is high; inspect ventilation and compare output trend.");
  if (dirtyPanel && !cleanerRunning && digitalRead(CLEANER_FAR_PIN) == HIGH) runCleanerTowardFarEnd();
}

void setup() {
  Serial.begin(115200);
  analogReadResolution(12);
  Wire.begin(21, 22);
  pinMode(CLEANER_HOME_PIN, INPUT_PULLUP);
  pinMode(CLEANER_FAR_PIN, INPUT_PULLUP);
  pinMode(TB_AIN1_PIN, OUTPUT);
  pinMode(TB_AIN2_PIN, OUTPUT);
  pinMode(TB_STBY_PIN, OUTPUT);
  digitalWrite(TB_STBY_PIN, HIGH);
  ledcAttach(TB_PWMA_PIN, 20000, 8);
  stopCleaner();
  azimuthServo.setPeriodHertz(50);
  elevationServo.setPeriodHertz(50);
  azimuthServo.attach(AZIMUTH_SERVO_PIN, 500, 2500);
  elevationServo.attach(ELEVATION_SERVO_PIN, 500, 2500);
  azimuthServo.write(azimuthDeg);
  elevationServo.write(elevationDeg);
  panelTemperature.begin();
  if (!ina219.begin()) Serial.println("INA219 not found; check its 3.3V, GND, SDA, and SCL wires.");
  if (!bme.begin(0x76)) Serial.println("BME280 not found; check its 3.3V, GND, SDA, SCL, and SDO-to-GND wires.");
}

void loop() {
  if (cleanerRunning) {
    if (!cleanerReturning && digitalRead(CLEANER_FAR_PIN) == LOW) {
      returnCleanerHome();
      Serial.println("Cleaner reached the far limit and is returning home.");
    } else if (cleanerReturning && digitalRead(CLEANER_HOME_PIN) == LOW) {
      stopCleaner();
      Serial.println("Cleaner returned to the home limit.");
    } else if (millis() - cleanerStartMs > CLEAN_TIMEOUT_MS) {
      stopCleaner();
      Serial.println("Cleaner stopped because its travel timeout expired.");
    }
  }
  if (millis() - lastSampleMs < SENSOR_PERIOD_MS) return;
  lastSampleMs = millis();
  int nw = readAverage(LDR_NW_PIN);
  int ne = readAverage(LDR_NE_PIN);
  int sw = readAverage(LDR_SW_PIN);
  int se = readAverage(LDR_SE_PIN);
  int dust = readAverage(DUST_PIN);
  updateTracker(nw, ne, sw, se);
  panelTemperature.requestTemperatures();
  float panelC = panelTemperature.getTempCByIndex(0);
  float airC = bme.readTemperature();
  float humidity = bme.readHumidity();
  float busVoltage = ina219.getBusVoltage_V();
  float currentmA = ina219.getCurrent_mA();
  reportMaintenance((nw + ne + sw + se) / 4, dust, busVoltage, currentmA, panelC, airC, humidity);
}