wemos_chirp.ino

#include <SPI.h>
#include <ESP8266WiFi.h>
#include <Wire.h>
#include <SFE_MicroOLED.h>

#define PIN_RESET 255  //
#define DC_JUMPER 0  // I2C Addres: 0 - 0x3C, 1 - 0x3D

MicroOLED oled(PIN_RESET, DC_JUMPER);

// Wifi and ThingSpeak settings
const char* ssid = "YourSSID";
char* password = "YourPassword";
 
const char* server = "api.thingspeak.com";
const char* api_key = "YourApiKey";

// Measurement interval (seconds)
const int sleepTimeS = 10; // 10 secs
#define LED D4

int moisture, light, i;
 
WiFiClient client;

void printFormattedFloat(float x, uint8_t precision) {
char buffer[10];

  dtostrf(x, 7, precision, buffer);
  Serial.print(buffer);

}

void postChirp(int moisture, int light){
  if (client.connect(server,80)) {
  Serial.println("Connect to ThingSpeak - OK");
  
  String dataToThingSpeak = "";
  dataToThingSpeak+="GET /update?api_key=";
  dataToThingSpeak+=api_key;
   
  dataToThingSpeak+="&field1=";
  dataToThingSpeak+=String(moisture);

  dataToThingSpeak+="&field2=";
  dataToThingSpeak+=String(light);
   
  dataToThingSpeak+=" HTTP/1.1\r\nHost: a.c.d\r\nConnection: close\r\n\r\n";
  dataToThingSpeak+="";
  client.print(dataToThingSpeak);

  int timeout = millis() + 5000;
  while (client.available() == 0) {
    if (timeout - millis() < 0) {
      Serial.println("Error: Client Timeout!");
      client.stop();
      return;
      }
    } 
  }
}

void writeI2CRegister8bit(int addr, int value) {
  Wire.beginTransmission(addr);
  Wire.write(value);
  Wire.endTransmission();
}

unsigned int readI2CRegister16bit(int addr, int reg) {
  Wire.beginTransmission(addr);
  Wire.write(reg);
  Wire.endTransmission();
  delay(1100);
  Wire.requestFrom(addr, 2);
  unsigned int t = Wire.read() << 8;
  t = t | Wire.read();
  return t;
}

// Setup wire and serial
void setup(){
  Wire.begin();
  Serial.begin(9600);
  pinMode(LED, OUTPUT);
  delay(10);

  oled.begin();
  oled.clear(PAGE);
  oled.clear(ALL);
  oled.setCursor(0, 0);
  
  oled.print("WLAN: ");
  oled.display();
  Serial.println("Connecting to wifi...");
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED){
    
    // Blink LED when connecting to wifi
    digitalWrite(LED, LOW);
    oled.setCursor(30, 0);
    oled.print("ASSOC");
    oled.display();
    delay(250);
    digitalWrite(LED, HIGH);
    oled.setCursor(30, 0);
    oled.print("     ");
    oled.display();
    delay(250);
  }
  
  oled.setCursor(30, 0);
  oled.print("     ");
  oled.setCursor(30, 0);
  oled.print("OK");
  oled.display();
  Serial.println("WiFi connected");

  oled.display();

  oled.setCursor(0, 10);
  oled.print("SWITCH NOW");
  oled.display();
  while(i < 10){   
    writeI2CRegister8bit(0x20, 3);
    light = readI2CRegister16bit(0x20, 4);
    oled.setCursor(0, 20);
    oled.print(light);
    oled.display();
    i++;
    delay(100);
  }
  oled.clear(PAGE);
  oled.clear(ALL);
}

// main loop
void loop(){
  Serial.print("Moisture: ");
  moisture = readI2CRegister16bit(0x20, 0);
  Serial.println(moisture);  //read capacitance register
  
  writeI2CRegister8bit(0x20, 3);                  //request light measurement 
  delay(10000);                                   //this can take a while
  Serial.print("Light: ");
  light = readI2CRegister16bit(0x20, 4);
  Serial.println(light);  //read light register
   
  Serial.println("=============");
  
  oled.clear(PAGE);
  oled.clear(ALL);
  oled.setCursor(0, 10);
  oled.print("MOI: ");
  oled.print(moisture);
  oled.setCursor(0, 20);
  oled.print("LUM: ");
  oled.print(light);
  oled.display();
  
  delay(38900);
  postChirp(moisture, light);
}