Published February 2, 2023

Monitoring of a LoRa antenna

Transmit information about the status of an energy-autonomous LoRa antenna, monitoring through a web interface

AdvancedWork in progress420

Things used in this project

Hardware components

Arduino MKR WAN 1310

DHT22 Temperature Sensor

Phasesun Phgaesun sunPlus 100

TP-Link Box 300Mbps Wireless N4G LTE Router

The Things Industries The Things Gateway

Batterie 12.7V 17AH RS PRO Sealed Lead-Acid Battery General Purpose Gel

ddr-15g-5

Régulateur solaire Steca, tension du panneau solaire 12 V, 24 V

SEN0291

Kit Carte Breakout Sigfox BRKWS01-RC1+Antenne 868Mhz

Seeed Studio Polymer Lithium Ion Battery - 2200mAh 3.7V

Chargeur utilisé pour charger de simples batteries en lithium-ion/lithium-polymère de 3,7 ou 4,2 V

Software apps and online services

Arduino IDE

KiCad

Ubidots

The Things Industries The Things Stack

Story

IoT is a rapidly expanding field. As the majority of appliances are subject to autonomy constraints, energy-efficient means of communication should be adopted. This involves the use of alternative communication networks, one of the most widespread being the LoRa network. Its popularity comes in particular from its low cost as well as its low consumption due to its relatively low throughput and relatively short range. Therefore, antennas should be installed to ensure reliable coverage of an area. Installed outdoors and subject to special conditions, its condition should be constantly monitored. Our project therefore aims to deploy an autonomous LoRa gateway in energy as well as the implementation of its monitoring through a Web interface.

Energy autonomy

Steca solar controller converts the voltage of the solar panel from 17v to 12v to charge the battery and then deliver energy to our system. The panel provides enough energy for our system to be self-contained.

Sensors

We used a 12v -> 5v converter to charge our 3.7v battery that will power the Arduino board. Even if our 12V battery is no longer charged, we have the 3.7V battery that will be our backup battery for the Arduino board.

With the divider bridge at the bort of the 12V battery we have an idea about the level of charge.

The sensors are connected to our Arduino. The power meter allows us to have the power value delivered by our solar panel to our 12V battery. The DHT22 sensor allows us to have the temperature and the humidity values.

Sending Data

We send the data with The Things Network. We created a webhook on TTN in connection with Ubidots. Then we recover the data from Ubidots after decoding to draw the curves so that the user could follow the status of the LoRa antenna. This data is sent every 5 minutes.

Perspective

We wanted to use Sigfox so that if the LoRa antenna no longer works, we can send our messages by Sigfox. But unfortunately, we do not have the Sigfox subscription. However, a place was granted to add a Sigfox antenna on the PCB.

Schematics

Code

gateway_lora.ino

#include <MKRWAN.h>
#include "DHT.h"
#define DHTTYPE DHT22
#include <Wire.h>
#include "DFRobot_INA219.h"

DFRobot_INA219_IIC     ina219(&Wire, INA219_I2C_ADDRESS4);

float ina219Reading_mA = 1000;
float extMeterReading_mA = 1000;
LoRaModem modem;
String appEui = "0000000000000010";
String appKey = "EE6231CA556EFD1B077B4C5CCEDCA01D";
bool connected;
int err_count;
short con;

// DHT Sensor
uint8_t DHTPin = 4;        
// Initialize DHT sensor.
DHT dht(DHTPin, DHTTYPE);                
float temperature;
float humidity;
void initDHT(){
  pinMode(DHTPin, INPUT);
  dht.begin();
}

void setup() {
  pinMode(A1, INPUT) ;
  initDHT();
  modem.begin(EU868);
  delay(1000); 
  // First use of capteur de puissance
  while(ina219.begin() != true) {
     delay(2000);
  }
  //Linear calibration
  ina219.linearCalibrate(ina219Reading_mA, extMeterReading_mA);
   connected=false;
  err_count=0;
  con =0;
}

void loop() {
  float resultBinary = analogRead(A1); // Rsultat de la mesure en binaire de la broche A0 (sur 10 bits de 0 (0 Volts)  1023 (5 volts) )
  temperature = dht.readTemperature(); 
  humidity = dht.readHumidity();
  // use the capteur de puissance
  while(ina219.begin() != true) {
        delay(2000);
  }
  if ( !connected ) {
    int ret=modem.joinOTAA(appEui, appKey);
    if ( ret ) {
      connected=true;
      modem.minPollInterval(60);
      modem.dataRate(5); // switch to SF7
      delay(100); // because ... more stable
      err_count=0;
    }
  }
  if ( connected ) {
    int err=0;
    modem.beginPacket();
    temperature *= 100;
    humidity*=100;
    short batterie = (((((3.3*resultBinary/1024)/1.02)*352/82)-11.1)/1.6)*100;
    modem.write((short) temperature);
    modem.write((short) humidity); 
    modem.write((short) ina219.getPower_mW());
    modem.write(batterie);
    err = modem.endPacket();
    err_count = 0;
    // wait for 5min
    delay(300000);
   }
}