ZsensorINA226.ino

/*  
  OpenMQTTGateway Addon  - ESP8266 or Arduino program for home automation 

   Act as a wifi or ethernet gateway between your 433mhz/infrared IR signal  and a MQTT broker 
   Send and receiving command by MQTT
 
    INA226 reading Addon
  
    From the orgiginal work of Matthias Busse http://shelvin.de/ein-batteriemonitor-fuer-strom-und-spannung-mit-dem-ina226-und-dem-arduino-uno/
    MQTT add - 1technophile
    
    Contributors:
    - 1technophile
  
    This file is part of OpenMQTTGateway.
    
    OpenMQTTGateway is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    OpenMQTTGateway is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
// Pinout
// INA226 - Uno - Mega - NODEMCU
// SCL    - A5  - 21 - D1
// SDA    - A4  - 20 - D2
//

#ifdef ZsensorINA226
#include <Wire.h>

float rShunt=0.1; // Shunt Widerstand festlegen, hier 0.1 Ohm
const int INA226_ADDR = 0x40; // A0 und A1 auf GND > Adresse 40 Hex auf Seite 18 im Datenblatt

//Time used to wait for an interval before resending temp and hum
unsigned long timeINA226 = 0;

void setupINA226() {
  Wire.begin();   
  // Configuration Register Standard Einstellung 0x4127, hier aber 16 Werte Mitteln > 0x4427
  writeRegister(0x00, 0x4427); // 1.1ms Volt und Strom A/D-Wandlung, Shunt und VBus continous
}

void MeasureINA226(){
    if (millis() > (timeINA226 + TimeBetweenReadingINA226)) {//retriving value of temperature and humidity of the box from DHT every xUL
        timeINA226 = millis();
        trc(F("Creating INA226 buffer"));
        StaticJsonBuffer<JSON_MSG_BUFFER> jsonBuffer;
        JsonObject& INA226data = jsonBuffer.createObject();
        // Topic on which we will send data
        trc(F("Retrieving electrical data"));
        // Bus Spannung, read-only, 16Bit, 0...40.96V max., LSB 1.25mV
        trc(F(" Volt: "));
        float volt = readRegister(0x02) * 0.00125; 
        trc(volt);
        trc(F(" V, Current: "));
        // Seite 24: Shunt Spannung +- 81,92mV mit 16 Bit, LSB 2,5uV
        int shuntvolt = readRegister(0x01);
        if (shuntvolt && 0x8000) {// eine negative Zahl? Dann 2er Komplement bilden
          shuntvolt = ~shuntvolt; // alle Bits invertieren
          shuntvolt += 1;         // 1 dazuzählen
          shuntvolt *= -1 ;       // negativ machen
        }
        float current = shuntvolt * 0.0000025 / rShunt; // * LSB / R
        trc(current);
        trc(F(" A, Power: "));
        float power=abs(volt*current);
        trc(power);
        trc(F(" W"));
      
        char volt_c[7];
        char current_c[7];
        char power_c[7];
        dtostrf(volt,6,3,volt_c);
        dtostrf(current,6,3,current_c);
        dtostrf(power,6,3,power_c);
        INA226data.set("Volt", (char *)volt_c);
        INA226data.set("Current", (char *)current_c);
        INA226data.set("Power", (char *)power_c);
        pub(subjectINA226toMQTT,INA226data);
    }
}

static void writeRegister(byte reg, word value) {
  Wire.beginTransmission(INA226_ADDR);
  Wire.write(reg);
  Wire.write((value >> 8) & 0xFF);
  Wire.write(value & 0xFF);
  Wire.endTransmission();
}

static word readRegister(byte reg) {
  word res = 0x0000;
  Wire.beginTransmission(INA226_ADDR);
  Wire.write(reg);
  if (Wire.endTransmission() == 0) {
    if (Wire.requestFrom(INA226_ADDR, 2) >= 2) {
      res  = Wire.read() * 256;
      res += Wire.read();
    }
  }
  return res;
}

#endif