Solar Plant Care System

#include <Arduino.h>
#include <Wire.h>
#include <WiFi.h>
#include <WebServer.h>
#include <Preferences.h>
#include <Adafruit_SHT31.h>
#include <BH1750.h>
#include <LiquidCrystal_I2C.h>

constexpr int SOIL1=1, SOIL2=2, FLOW=4, BATTERY=5, PUMP=10, FAN=11, LIGHT=12;
WebServer web(80);
Preferences prefs;
Adafruit_SHT31 sht;
BH1750 bh;
LiquidCrystal_I2C lcd(0x27,16,2);
volatile uint32_t pulses=0;
void IRAM_ATTR pulseISR(){pulses++;}
uint32_t pulseCount(){noInterrupts(); uint32_t n=pulses; interrupts();return n;}
bool shtOK=false,bhOK=false,lcdOK=false, armed=false, fault=false, lowBattery=true;
bool pump=false,fan=false,light=false;
int raw[2]={0,0},dry[2]={0,0},wet[2]={0,0},moist[2]={0,0};
float temp=NAN,rh=NAN,lux=NAN,bat=0,flowRate=0;
float pulsesPerLiter=5880;
uint32_t sampled=0,cycleStart=0,cyclePulses=0,lastFlow=0,lastPulse=0;
uint32_t cooldown=0,windowStart=0,usedPumpMs=0,fanStart=0,lightStart=0;
String ssid,pass, previous[2];
const char PAGE[] PROGMEM=R"HTML(<!doctype html><html><meta name="viewport" content="width=device-width"><title>Plant Solar Demo</title>
<h2>Plant Solar Demo</h2><p>Local dashboard. No cloud required.</p><pre id="v">Loading...</pre>
<form action="/wifi" method="post">Home Wi-Fi name <input name="ssid" maxlength="32"><br>Password <input name="pass" type="password" maxlength="63"><button>Save and connect</button></form>
<p>Calibrate each probe in dry soil, then fully wet, drained soil. Keep its electronics dry. Percent is a relative index, not scientific water content.</p>
<form action="/cal" method="post"><select name="probe"><option value="0">Probe 1</option><option value="1">Probe 2</option></select><button name="point" value="dry">Save dry</button><button name="point" value="wet">Save wet</button></form>
<form action="/arm" method="post"><button name="on" value="1">Arm automatic care</button><button name="on" value="0">STOP / disarm</button></form>
<form action="/clear" method="post"><button>Clear flow fault after checking water</button></form>
<p>One watering zone: both probes must be dry. Max 5 seconds/cycle, 30 minutes between cycles, 30 seconds per rolling hour of uptime. Reboot starts a 30-minute wait. Fan and light are demonstration duty cycles, not full climate control.</p>
<script>setInterval(()=>fetch('/status').then(r=>r.json()).then(v=>document.getElementById('v').textContent=JSON.stringify(v,null,2)),2000);</script></html>)HTML";
int avg(int pin){uint32_t s=0;for(int i=0;i<16;i++)s+=analogRead(pin);return s/16;}
bool calibrated(){return dry[0]-wet[0]>150 && dry[1]-wet[1]>150;}
bool validSoil(){return raw[0]>100 && raw[0]<4000 && raw[1]>100 && raw[1]<4000;}
void stopPump(){if(pump){usedPumpMs+=millis()-cycleStart;cooldown=millis();}pump=false;digitalWrite(PUMP,LOW);}
void allOff(){stopPump();fan=light=false;digitalWrite(FAN,LOW);digitalWrite(LIGHT,LOW);}
void reply(){web.sendHeader("Location","/");web.send(303,"text/plain","");}
String number(float f,int places=1){return isfinite(f)?String(f,places):String("null");}
void status(){
 String s="{\"temperature_C\":"+number(temp)+",\"humidity_pct\":"+number(rh)+",\"lux\":"+number(lux)+",\"battery_V\":"+number(bat,2);
 s+=",\"soil1_raw\":"+String(raw[0])+",\"soil2_raw\":"+String(raw[1]);
 s+=",\"soil1_pct\":"+(calibrated()?String(moist[0]):String("null"))+",\"soil2_pct\":"+(calibrated()?String(moist[1]):String("null"));
 s+=",\"flow_L_min\":"+number(flowRate,3)+",\"volume_L_since_boot\":"+String(pulseCount()/pulsesPerLiter,3);
 s+=",\"armed\":"+String(armed?"true":"false")+",\"flow_fault\":"+String(fault?"true":"false")+",\"low_battery\":"+String(lowBattery?"true":"false");
 s+=",\"pump\":"+String(pump?"true":"false")+",\"fan\":"+String(fan?"true":"false")+",\"light\":"+String(light?"true":"false")+",\"station_ip\":\""+WiFi.localIP().toString()+"\"}";
 web.send(200,"application/json",s);
}
void showLine(int row,String s){while(s.length()<16)s+=' ';s=s.substring(0,16);if(s!=previous[row]){lcd.setCursor(0,row);lcd.print(s);previous[row]=s;}}
void setup(){
 for(int p:{PUMP,FAN,LIGHT}){digitalWrite(p,LOW);pinMode(p,OUTPUT);}Serial.begin(115200);
 pinMode(FLOW,INPUT);attachInterrupt(digitalPinToInterrupt(FLOW),pulseISR,RISING);
 analogReadResolution(12);analogSetAttenuation(ADC_11db);Wire.begin(8,9);Wire.setClock(100000);Wire.setTimeOut(50);
 shtOK=sht.begin(0x44);bhOK=bh.begin(BH1750::CONTINUOUS_HIGH_RES_MODE);
 Wire.beginTransmission(0x27);lcdOK=Wire.endTransmission()==0;
 if(lcdOK){lcd.init();lcd.noBacklight();}
 prefs.begin("plant",false);for(int i=0;i<2;i++){dry[i]=prefs.getInt(("dry"+String(i)).c_str(),0);wet[i]=prefs.getInt(("wet"+String(i)).c_str(),0);}
 ssid=prefs.getString("ssid","");pass=prefs.getString("pass","");
 WiFi.mode(WIFI_AP_STA);WiFi.softAP("PlantSolar-Setup","PlantDemo42");if(ssid.length())WiFi.begin(ssid.c_str(),pass.c_str());
 web.on("/",HTTP_GET,[]{web.send_P(200,"text/html",PAGE);});web.on("/status",HTTP_GET,status);
 web.on("/wifi",HTTP_POST,[]{ssid=web.arg("ssid");pass=web.arg("pass");prefs.putString("ssid",ssid);prefs.putString("pass",pass);WiFi.begin(ssid.c_str(),pass.c_str());reply();});
 web.on("/cal",HTTP_POST,[]{int i=web.arg("probe").toInt();if(i>=0&&i<2&&!pump){int n=avg(i?SOIL2:SOIL1);String key=web.arg("point");if(key=="dry"||key=="wet"){if(key=="dry")dry[i]=n;else wet[i]=n;prefs.putInt((key+String(i)).c_str(),n);armed=false;allOff();}}reply();});
 web.on("/arm",HTTP_POST,[]{armed=web.arg("on")=="1"&&calibrated()&&validSoil()&&!lowBattery&&!fault;if(!armed)allOff();reply();});
 web.on("/clear",HTTP_POST,[]{allOff();armed=false;fault=false;cooldown=millis();reply();});
 web.begin();cooldown=windowStart=millis();Serial.println("Connect PlantSolar-Setup / PlantDemo42 then open http://192.168.4.1");
}
void loop(){
 web.handleClient();uint32_t now=millis();
 if(now-sampled>=2000 || sampled==0){sampled=now;
  raw[0]=avg(SOIL1);raw[1]=avg(SOIL2);
  for(int i=0;i<2;i++)if(dry[i]-wet[i]>150)moist[i]=constrain((dry[i]-raw[i])*100/(dry[i]-wet[i]),0,100);
  uint32_t mv=0;for(int i=0;i<16;i++)mv+=analogReadMilliVolts(BATTERY);bat=mv/16.0f*2/1000;
  if(bat<3.5 || bat>4.3)lowBattery=true;else if(bat>3.8)lowBattery=false;
  temp=shtOK?sht.readTemperature():NAN;rh=shtOK?sht.readHumidity():NAN;
  lux=bhOK?bh.readLightLevel():NAN;if(lux<0)lux=NAN;
  uint32_t n=pulseCount();if(lastFlow)flowRate=(n-lastPulse)*60000.0f/(now-lastFlow)/pulsesPerLiter;lastFlow=now;lastPulse=n;
  if(lcdOK){if((now/5000)%2){showLine(0,"Soil "+String(moist[0])+"/"+String(moist[1])+"%");showLine(1,fault?"FLOW FAULT":(armed?"ARMED ":"SAFE ")+String(bat,2)+"V");}else{showLine(0,String(temp,1)+"C "+String(rh,0)+"%RH");showLine(1,"Lux "+String(lux,0));}}
 }
 if(!armed||lowBattery||!validSoil()||!calibrated()){allOff();return;}
 if(now-windowStart>=3600000UL){windowStart=now;usedPumpMs=0;}
 if(pump){
  if(now-cycleStart>=3000 && pulseCount()==cyclePulses){fault=true;armed=false;allOff();}
  else if(now-cycleStart>=5000 || pulseCount()-cyclePulses>=uint32_t(pulsesPerLiter*.1f) || usedPumpMs+(now-cycleStart)>=30000)stopPump();
  return;
 }
 if(!fault && moist[0]<35 && moist[1]<35 && now-cooldown>=1800000UL && usedPumpMs<30000){
  fan=light=false;digitalWrite(FAN,LOW);digitalWrite(LIGHT,LOW);pump=true;cycleStart=now;cyclePulses=pulseCount();digitalWrite(PUMP,HIGH);return;
 }
 // Time-sliced demonstration limits: fan <=60s/5min, light <=60s/10min.
 bool wantFan=isfinite(temp)&&isfinite(rh)&&(temp>=30||rh>=85)&&(now%300000UL<60000);
 bool wantLight=!wantFan&&isfinite(lux)&&lux<1000&&(now%600000UL>=60000&&now%600000UL<120000);
 fan=wantFan;light=wantLight;digitalWrite(FAN,fan);digitalWrite(LIGHT,light);
 delay(2);
}