Automatische Pflanzenbewässerungskontrolle

#include <Arduino.h>
#include <Wire.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SH110X.h>
#include <RTClib.h>
#include <OneWire.h>
#include <DallasTemperature.h>
#include <Adafruit_ADS1X15.h>


// Forward declarations
int readAverageAnalog(uint8_t pin);
int clampPercent(int value);
int soilRawToPercent(int raw);
float readWaterDistanceCm();
void updatePump();
void updateHeater();
void readSensors();
void drawDisplay();

constexpr uint8_t SOIL_PIN = A0;
constexpr uint8_t MOISTURE_MIN_PIN = A1;
constexpr uint8_t MOISTURE_MAX_PIN = A2;
constexpr uint8_t DAY_TEMP_PIN = A3;
constexpr uint8_t DS18B20_PIN = 2;
constexpr uint8_t ULTRASONIC_TRIG_PIN = 9;
constexpr uint8_t ULTRASONIC_ECHO_PIN = 10;
constexpr uint8_t PUMP_RELAY_PIN = 6;
constexpr uint8_t HEATER_RELAY_PIN = 7;

constexpr uint8_t OLED_ADDRESS = 0x3C;
constexpr uint8_t ADS1115_ADDRESS = 0x48;
constexpr uint8_t RELAY_ON = LOW;   // Typical opto relay modules are active LOW.
constexpr uint8_t RELAY_OFF = HIGH;
constexpr int TANK_HEIGHT_CM = 18;
constexpr float MIN_ALLOWED_TEMPERATURE = 5.0f;
constexpr float MAX_ALLOWED_TEMPERATURE = 35.0f;
constexpr float HEATER_HYSTERESIS_C = 0.5f;
constexpr unsigned long PUMP_PULSE_MS = 2500;
constexpr unsigned long SOAK_TIME_MS = 30000;
constexpr unsigned long SENSOR_INTERVAL_MS = 1000;
constexpr unsigned long DISPLAY_INTERVAL_MS = 1000;

// Calibrate these two values for the actual soil and sensor before normal use.
// Readings fall when the sensor is wetter: dry = larger number, wet = smaller number.
constexpr int SOIL_RAW_WET = 5200;
constexpr int SOIL_RAW_DRY = 11800;

Adafruit_SH1106G display(128, 64, &Wire, -1);
RTC_DS3231 rtc;
OneWire oneWire(DS18B20_PIN);
DallasTemperature temperatureBus(&oneWire);
Adafruit_ADS1115 ads;

bool displayReady = false;
bool rtcReady = false;
bool adsReady = false;
bool pumpRunning = false;
bool heaterRunning = false;
bool pumpLockout = false;
unsigned long pumpStartedAt = 0;
unsigned long pumpStoppedAt = 0;
unsigned long lastSensorAt = 0;
unsigned long lastDisplayAt = 0;

int soilPercent = 0;
int minMoisturePercent = 30;
int maxMoisturePercent = 60;
int waterLevelPercent = 0;
float waterDistanceCm = -1.0f;
float measuredTemperatureC = NAN;
float dayTargetC = 20.0f;
float nightTargetC = 16.0f;
float activeTargetC = 20.0f;
bool isDay = true;

int readAverageAnalog(uint8_t pin) {
  long total = 0;
  for (uint8_t i = 0; i < 8; ++i) {
    total += analogRead(pin);
    delay(2);
  }
  return total / 8;
}

int clampPercent(int value) {
  return constrain(value, 0, 100);
}

int soilRawToPercent(int raw) {
  long percent = map(raw, SOIL_RAW_DRY, SOIL_RAW_WET, 0, 100);
  return clampPercent((int)percent);
}

float readWaterDistanceCm() {
  digitalWrite(ULTRASONIC_TRIG_PIN, LOW);
  delayMicroseconds(3);
  digitalWrite(ULTRASONIC_TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(ULTRASONIC_TRIG_PIN, LOW);
  unsigned long duration = pulseIn(ULTRASONIC_ECHO_PIN, HIGH, 30000);
  if (duration == 0) return -1.0f;
  return duration * 0.0343f / 2.0f;
}

void updatePump() {
  unsigned long now = millis();
  if (pumpRunning && now - pumpStartedAt >= PUMP_PULSE_MS) {
    digitalWrite(PUMP_RELAY_PIN, RELAY_OFF);
    pumpRunning = false;
    pumpLockout = true;
    pumpStoppedAt = now;
  }

  if (pumpLockout && now - pumpStoppedAt >= SOAK_TIME_MS) {
    pumpLockout = false;
  }

  bool tankHasWater = waterLevelPercent > 5;
  if (!pumpRunning && !pumpLockout && tankHasWater && soilPercent < minMoisturePercent) {
    digitalWrite(PUMP_RELAY_PIN, RELAY_ON);
    pumpRunning = true;
    pumpStartedAt = now;
  }

  // The max value ends irrigation immediately; this is the upper safety limit.
  if (pumpRunning && soilPercent >= maxMoisturePercent) {
    digitalWrite(PUMP_RELAY_PIN, RELAY_OFF);
    pumpRunning = false;
    pumpLockout = true;
    pumpStoppedAt = now;
  }
}

void updateHeater() {
  if (isnan(measuredTemperatureC)) {
    digitalWrite(HEATER_RELAY_PIN, RELAY_OFF);
    heaterRunning = false;
    return;
  }

  if (!heaterRunning && measuredTemperatureC <= activeTargetC - HEATER_HYSTERESIS_C) {
    digitalWrite(HEATER_RELAY_PIN, RELAY_ON);
    heaterRunning = true;
  } else if (heaterRunning && measuredTemperatureC >= activeTargetC + HEATER_HYSTERESIS_C) {
    digitalWrite(HEATER_RELAY_PIN, RELAY_OFF);
    heaterRunning = false;
  }
}

void readSensors() {
  int soilRaw = readAverageAnalog(SOIL_PIN);
  soilPercent = soilRawToPercent(soilRaw);
  minMoisturePercent = clampPercent(map(readAverageAnalog(MOISTURE_MIN_PIN), 0, 16383, 0, 100));
  maxMoisturePercent = clampPercent(map(readAverageAnalog(MOISTURE_MAX_PIN), 0, 16383, 0, 100));
  if (maxMoisturePercent < minMoisturePercent + 5) {
    maxMoisturePercent = min(100, minMoisturePercent + 5);
  }

  dayTargetC = map(readAverageAnalog(DAY_TEMP_PIN), 0, 16383, 100, 350) / 10.0f;
  if (adsReady) {
    int16_t nightRaw = ads.readADC_SingleEnded(0);
    nightTargetC = map(nightRaw, 0, 17600, 100, 350) / 10.0f;
  }
  dayTargetC = constrain(dayTargetC, MIN_ALLOWED_TEMPERATURE, MAX_ALLOWED_TEMPERATURE);
  nightTargetC = constrain(nightTargetC, MIN_ALLOWED_TEMPERATURE, MAX_ALLOWED_TEMPERATURE);

  if (rtcReady) {
    DateTime now = rtc.now();
    isDay = now.hour() >= 7 && now.hour() < 22;
  } else {
    isDay = true;
  }
  activeTargetC = isDay ? dayTargetC : nightTargetC;

  temperatureBus.requestTemperatures();
  float newTemperature = temperatureBus.getTempCByIndex(0);
  measuredTemperatureC = (newTemperature == DEVICE_DISCONNECTED_C) ? NAN : newTemperature;

  waterDistanceCm = readWaterDistanceCm();
  if (waterDistanceCm >= 0.0f) {
    waterLevelPercent = clampPercent((int)round((TANK_HEIGHT_CM - waterDistanceCm) * 100.0f / TANK_HEIGHT_CM));
  } else {
    waterLevelPercent = 0;
  }
}

void drawDisplay() {
  if (!displayReady) return;
  display.clearDisplay();
  display.setTextColor(SH110X_WHITE);
  display.setTextSize(1);
  display.setCursor(0, 0);
  display.print("Feuchte: ");
  display.print(soilPercent);
  display.println(" %");
  display.print("Feuchte min.: ");
  display.print(minMoisturePercent);
  display.println(" %");
  display.print("Feuchte max.: ");
  display.print(maxMoisturePercent);
  display.println(" % ");
  display.print("Wasser: ");
  display.print(waterLevelPercent);
  display.println(" %");
  display.print("Temp ");
  if (isnan(measuredTemperatureC)) display.print("--.-");
  else display.print(measuredTemperatureC, 1);
  display.print("/");
  display.print(activeTargetC, 1);
  display.println(" C");
  display.print(isDay ? "Tag " : "Nacht ");
  display.print("P:");
  display.print(pumpRunning ? "AN" : "AUS");
  display.print(" H:");
  display.println(heaterRunning ? "AN" : "AUS");
  display.display();
}

void setup() {
  pinMode(ULTRASONIC_TRIG_PIN, OUTPUT);
  pinMode(ULTRASONIC_ECHO_PIN, INPUT);
  pinMode(PUMP_RELAY_PIN, OUTPUT);
  pinMode(HEATER_RELAY_PIN, OUTPUT);
  digitalWrite(PUMP_RELAY_PIN, RELAY_OFF);
  digitalWrite(HEATER_RELAY_PIN, RELAY_OFF);

  analogReadResolution(14);
  Wire.begin();
  temperatureBus.begin();

  displayReady = display.begin(OLED_ADDRESS, true);
  rtcReady = rtc.begin();
  if (rtcReady && rtc.lostPower()) rtc.adjust(DateTime(F(__DATE__), F(__TIME__)));
  adsReady = ads.begin(ADS1115_ADDRESS);
  if (adsReady) ads.setGain(GAIN_ONE);

  readSensors();
  updatePump();
  updateHeater();
  drawDisplay();
}

void loop() {
  unsigned long now = millis();
  if (now - lastSensorAt >= SENSOR_INTERVAL_MS) {
    lastSensorAt = now;
    readSensors();
    updateHeater();
  }
  updatePump();
  if (now - lastDisplayAt >= DISPLAY_INTERVAL_MS) {
    lastDisplayAt = now;
    drawDisplay();
  }
}