m5stack env sensor

m5stack-env-sensor.ino

/*
* This code is example to get environment variable and upload to google spreadsheet.
* 
* Requirements:
* - M5STACK (I tested this code on M5STACK FIRE)
* - Adafruit_BMP280 library
* - DHT12 library
*
* Usage:
* - Connect env unit to M5Stack port A.
*/

#include <Wire.h>
#include <WiFi.h>
#include <M5Stack.h>
#include <HTTPClient.h>

#include "DHT12.h"
#include "Adafruit_Sensor.h"
#include "Adafruit_BMP280.h"
#include "preferences.h"

#define BATTERY_LEVEL_SUPPORT true

DHT12 dht12; //Preset scale CELSIUS and ID 0x5c.
Adafruit_BMP280 bme;

unsigned long t = 0;
unsigned long lastUploaded = 0;
const int sensorPollingInterval = 1000 * 1;
const int uploadInterval = 1000 * 60 * 5;

uint8_t hh;
uint8_t mm;
uint8_t ss;
struct tm timeInfo;

void setup() {
  M5.begin();
  Wire.begin();

  M5.Lcd.setBrightness(10);

  Serial.println(F("ENV Unit(DHT12 and BMP280) test..."));

  if (!bme.begin(0x76)) {
    Serial.println("Could not find a valid BMP280 sensor, check wiring!");
    while (1);
  }
  M5.Lcd.println("ENV Unit test...");

  Serial.print("[WiFi] Attempting to connect to SSID: ");
  WiFi.mode(WIFI_STA);
  WiFi.disconnect();
  Serial.println(wifiSSID);

  setupWiFi();
  configTime(9 * 3600L, 0, "ntp.nict.jp", "time.google.com", "ntp.jst.mfeed.ad.jp");
}

void loop() {
  getLocalTime(&timeInfo);
  hh = timeInfo.tm_hour;
  mm = timeInfo.tm_min;
  ss = timeInfo.tm_sec;

  t = millis();

  float tmp = dht12.readTemperature();
  float hum = dht12.readHumidity();
  float pressure = bme.readPressure();
  Serial.printf("Time: %d  Last Uploaded: %d\r\nTemperature: %2.2fC  Humidity: %0.2f%%  Pressure: %0.2fhPa\r\n", t, lastUploaded, tmp, hum, pressure / 100);

  M5.Lcd.setCursor(0, 0);
  M5.Lcd.setTextColor(WHITE, BLACK);
  M5.Lcd.setTextSize(3);
  M5.Lcd.printf("Time: %02d:%02d:%02d\r\nTemp: %2.1fC\r\nHumidity: %2.0f%%\r\nPress: %2.1fhPa\r\n", hh, mm, ss, t, tmp, hum, pressure / 100);

#ifdef BATTERY_LEVEL_SUPPORT
  M5.Lcd.printf("BAT Level  %d%%", getBatteryLevel());
#endif

  if (lastUploaded == 0 || lastUploaded + uploadInterval <= millis()) {
    postJson(tmp, hum, pressure);
    lastUploaded = t;
    Serial.printf("Next upload time after %d seconds\r\n", (lastUploaded + uploadInterval) / 1000);
  }

  delay(sensorPollingInterval);
}

// get battery level from charge IC
// see: https://github.com/m5stack/M5Stack/issues/74
int8_t getBatteryLevel() {
  Wire.beginTransmission(0x75);
  Wire.write(0x78);
  if (Wire.endTransmission(false) == 0 && Wire.requestFrom(0x75, 1)) {
    switch (Wire.read() & 0xF0) {
      case 0xE0: return 25;
      case 0xC0: return 50;
      case 0x80: return 75;
      case 0x00: return 100;
      default: return 0;
    }
  }
  return -1;
}

void setupWiFi() {
  if (WiFi.status() != WL_CONNECTED) {
    Serial.print("[WiFi] waiting for connection");

    WiFi.begin(wifiSSID, wifiPassword);
    while (WiFi.status() != WL_CONNECTED) {
      delay(500);
      Serial.print(".");
    }
    Serial.println("connected!");

    Serial.print("[WiFi] Connected to ");
    Serial.println(wifiSSID);
  }
}

void postJson(float tmp, float hum, float pressure) {
  setupWiFi();

  //make JSON
  char json[100];
  sprintf(json, "{\"temp\": %2.2f , \"humid\": %2.2f, \"pressure\": %2.2f}", tmp, hum, pressure / 100);

  //HTTPClient code start
  HTTPClient http;

  // configure traged server and url
  Serial.print("[HTTP] Begin...\n");
  http.begin(spreadsheetUrl); //HTTP

  Serial.print("[HTTP] POST started...\n");
  // start connection and send HTTP header
  int httpCode = http.POST(json);

  // httpCode will be negative on error
  if (httpCode > 0) {
    // HTTP header has been send and Server response header has been handled
    Serial.printf("[HTTP] POST finished... code: %d\n", httpCode);

    // file found at server
    if (httpCode == HTTP_CODE_OK) {
      String payload = http.getString();
      Serial.println(payload);
    }
  } else {
    Serial.printf("[HTTP] POST... failed, error: %s\n", http.errorToString(httpCode).c_str());
  }

  http.end();
}