Station météo à monter soi-même. Elle est bâtie autour d'un devkit de type NodeMCU devKit version 3. Le pack contient:

• Une carte (devkit) de type NodeMCU 1.0 avec un module ESP12-E (intégrant un microcontrôleur ESP8266XE et 4MB de mémoire Flash). La carte est marquée HW-625
• un DHT11
• un circuit intégré BMP180
• un afficheur OLED I2C

• Installer l'IDE Arduino
• Installer la chaîne de compilation pour ESP8266

Configurer la cible en sélectionnant NodeMCU 1.0 parmi les cartes basées sur les microcontrôleurs ESP8266:

• Menu Outils → Type de carte → ESP8266 Boards → NodeMCU 1.0(ESP-12E Module)

La documentation du kit IdeaSpark recommande de flasher le firmware:

• Ai-Thinker_ESP8266_DOUT_8Mbit_v1.5.4.1-a_20171130.bin contenu dans le fichier doc

On peut utiliser l'outil en ligne de commande esptool pour flasher le firmware:

$ esptool.py --port /dev/ttyUSB0 flash_id
esptool.py v2.8
Serial port /dev/ttyUSB0
Connecting....
Detecting chip type... ESP8266
Chip is ESP8266EX
Features: WiFi
Crystal is 26MHz
MAC: 50:02:91:e0:a2:de
Uploading stub...
Running stub...
Stub running...
Manufacturer: ef
Device: 4016
Detected flash size: 4MB
Hard resetting via RTS pin...

cd /tmp
wget "https://github.com/GJKJ/WSKS/blob/master/WSK.rar"

Lancer l'IDE Arduino:

• Menu Croquis → Inclure une bibliothèque → Gérer les bibliothèques
• Rechercher et installer ESP8266 Weather Station et sa dépendance JSON Streaming Parser
• Rechercher et installer ESP8266 OLED Driver for SSD1306 display
• Rechercher et installer Adafruit BMP085 Library ainsi que ses dépendances (Adafruit Unified Sensor et Adafruit BusIO)

Pour faciliter la mise en service de la station, j'ai fait le choix de monter et tester chaque module indépendamment. Une fois le montage validé, le programme pourra être téléversé.

testDHT11.ino

#define pin 14       // ESP8266-12E  D5 read emperature and Humidity data
int temp = 0; //temperature
int humi = 0; //humidity
void readTemperatureHumidity();
void uploadTemperatureHumidity();
 
void setup() {
  Serial.begin(115200);
}
 
void loop() {
 
readTemperatureHumidity();
delay(4000);
 
}
 
//read temperature humidity data
void readTemperatureHumidity(){
  int j;
  unsigned int loopCnt;
  int chr[40] = {0};
  unsigned long time1;
bgn:   
  delay(2000);
  //Set interface mode 2 to: output
  //Output low level 20ms (>18ms)
  //Output high level 40μs
  pinMode(pin, OUTPUT);
  digitalWrite(pin, LOW);
  delay(20);
  digitalWrite(pin, HIGH);
  delayMicroseconds(40);
  digitalWrite(pin, LOW);
  //Set interface mode 2: input
  pinMode(pin, INPUT);
  //High level response signal
  loopCnt = 10000;
  while (digitalRead(pin) != HIGH){
    if (loopCnt-- == 0){
      //If don't return to high level for a long time, output a prompt and start over
      Serial.println("HIGH");
      goto bgn;
    }
  }
  //Low level response signal
  loopCnt = 30000;
  while (digitalRead(pin) != LOW){
    if (loopCnt-- == 0){
      //If don't return low for a long time, output a prompt and start over
      Serial.println("LOW");
      goto bgn;
    }
  }
  //Start reading the value of bit1-40
  for (int i = 0; i < 40; i++){
    while (digitalRead(pin) == LOW){}
    //When the high level occurs, write down the time "time"
    time1 = micros();
    while (digitalRead(pin) == HIGH){}
    //When there is a low level, write down the time and subtract the time just saved
    //If the value obtained is greater than 50μs, it is ‘1’, otherwise it is ‘0’
    //And save it in an array
    if (micros() - time1  > 50){
      chr[i] = 1;
    } else {
      chr[i] = 0;
    }
  }
 
  //Humidity, 8-bit bit, converted to a value
  humi = chr[0] * 128 + chr[1] * 64 + chr[2] * 32 + chr[3] * 16 + chr[4] * 8 + chr[5] * 4 + chr[6] * 2 + chr[7];
  //Temperature, 8-bit bit, converted to a value
  temp = chr[16] * 128 + chr[17] * 64 + chr[18] * 32 + chr[19] * 16 + chr[20] * 8 + chr[21] * 4 + chr[22] * 2 + chr[23];
 
    Serial.print("temp:");
    Serial.print(temp);
    Serial.print("    humi:");
    Serial.println(humi);
 
}

SCL → D1 SDA → D2

test_BH1750FVI.ino

#include <Wire.h>
 
const int Light_ADDR = 0b0100011;   // address:0x23
 
int tempLight = 0;
 
void readLight();
 
void setup() {
   Serial.begin(115200);
 
  Wire.begin();
 
  //initialize light sensor
  Wire.beginTransmission(Light_ADDR);
  Wire.write(0b00000001);
  Wire.endTransmission();
 
}
 
void loop() {
  readLight();
  delay(5000);
}
 
void readLight(){
  // reset
  Wire.beginTransmission(Light_ADDR);
  Wire.write(0b00000111);
  Wire.endTransmission();
 
  Wire.beginTransmission(Light_ADDR);
  Wire.write(0b00100000);
  Wire.endTransmission();
  // typical read delay 120ms
  delay(120);
  Wire.requestFrom(Light_ADDR, 2); // 2byte every time
  for (tempLight = 0; Wire.available() >= 1; ) {
    char c = Wire.read();
    tempLight = (tempLight << 8) + (c & 0xFF);
  }
  tempLight = tempLight / 1.2;
  Serial.print("light: ");
  Serial.println(tempLight);
}

• https://github.com/GJKJ/WSKS
• https://github.com/ThingPulse/esp8266-weather-station
• https://create.arduino.cc/projecthub/luciorocha/ai-thinker-ai-cloud-inside-esp8266-update-firmware-reviewed-3e306c
• https://www.esp8266.com/viewtopic.php?t=6260
• https://robertoostenveld.nl/esp8266-at-firmware/
• https://github.com/espressif/ESP8266_NONOS_SDK
• https://github.com/espressif/ESP8266_AT (n'est plus maintenu)
• https://docs.espressif.com/projects/esp-at/en/latest/
• https://docs.espressif.com/projects/esp-at/en/latest/Get_Started/Downloading_guide.html