[IoT EDGE V.3 Board] LoRa Communication Test. , Heltec CubeCell Capsule MPU9250

Supphakarin Phoruangrong

4 min readMay 17, 2021

Device

IoT EDGE V.3 Board
LoRa Shield Dragino V.1.4
CubCell Capsule MPU9250 (Accelerator)

Software

Arduino IDE 2.0 Beta(Download)

Library for Arduino IDE

CauCell Capsule (Download)
LoRa (Download)

Model Test

IoT EDGE V.3 Board + LoRa Shield (Receive)
CubCell Capsule MPU9250(Node)

Source Code

IoT EDGE V.3 + LoRa, Gyrosecope (Download)

Explain

ในการทดสอบการใช้งานบอร์ด IoT EAGE V.3 ในบทความนี้ความจะทดสอบการสื่อสารแบบ LoRa ใช้ในการส่งข้อมูลระหว่าง ตัวรับ(Receive) และ ตัวส่งข้อมูล(Node) ในตัวของตัวส่งมี การวัดความเร่ง ของ Heltec MPU9250
ความถี่ที่ใช้งาน 915 MHz โดยจะใช้หลักการในการส่งใช้แบบ LoRa Modulation

Method

Install CubCell Capsule Heltec

Open Arduino 2.0 Beta → File → Preferences → Copy URL → Press on Additional boards manager URLs : → Ok

https://resource.heltec.cn/download/package_CubeCell_index.json

2.Search Board

Tools → Board → Boards Manager → click → Search : CubeCell → Install

3.เขียน Code

IoT EDGE V.3 + LoRa Shield

#include <SPI.h>
#include <LoRa.h>
#define ss 2
#define reset 17
#define dio0 26void setup() {
  Serial.begin(115200);
  while (!Serial);
  LoRa.setPins(ss, reset, dio0);
  Serial.println("LoRa Receiver");if (!LoRa.begin(915E6)) {
    Serial.println("Starting LoRa failed!");
    while (1);
  }
}void loop() {
  // try to parse packet
  int packetSize = LoRa.parsePacket();
  if (packetSize) {
    // received a packet
    Serial.print("Received packet '");// read packet
    while (LoRa.available()) {
      Serial.print((char)LoRa.read());
    }// print RSSI of packet
    Serial.print("' with RSSI ");
    Serial.println(LoRa.packetRssi());
  }
}

Capsule MPU9250

#include "LoRaWan_APP.h"
#include "Arduino.h"
#include <Wire.h>
#include <MPU9250.h>
MPU9250 mySensor;/*
 * set LoraWan_RGB to 1,the RGB active in loraWan
 * RGB red means sending;
 * RGB green means received done;
 */
#ifndef LoraWan_RGB
#define LoraWan_RGB 0
#endif#define RF_FREQUENCY                                915000000 // Hz#define TX_OUTPUT_POWER                             14        // dBm#define LORA_BANDWIDTH                              0         // [0: 125 kHz,
                                                              //  1: 250 kHz,
                                                              //  2: 500 kHz,
                                                              //  3: Reserved]
#define LORA_SPREADING_FACTOR                       7         // [SF7..SF12]
#define LORA_CODINGRATE                             1         // [1: 4/5,
                                                              //  2: 4/6,
                                                              //  3: 4/7,
                                                              //  4: 4/8]
#define LORA_PREAMBLE_LENGTH                        8         // Same for Tx and Rx
#define LORA_SYMBOL_TIMEOUT                         0         // Symbols
#define LORA_FIX_LENGTH_PAYLOAD_ON                  false
#define LORA_IQ_INVERSION_ON                        false#define RX_TIMEOUT_VALUE                            1000
#define BUFFER_SIZE                                 30 // Define the payload size herechar txpacket[BUFFER_SIZE];
char rxpacket[BUFFER_SIZE];static RadioEvents_t RadioEvents;double txNumber;int16_t rssi,rxSize;
void  DoubleToString( char *str, double double_num,unsigned int len);void setup() {
    Serial.begin(115200);
    Wire.begin();
    txNumber=0;
    rssi=0;Radio.Init( &RadioEvents );
    Radio.SetChannel( RF_FREQUENCY );
    Radio.SetTxConfig( MODEM_LORA, TX_OUTPUT_POWER, 0, LORA_BANDWIDTH,
                                   LORA_SPREADING_FACTOR, LORA_CODINGRATE,
                                   LORA_PREAMBLE_LENGTH, LORA_FIX_LENGTH_PAYLOAD_ON,
                                   true, 0, 0, LORA_IQ_INVERSION_ON, 3000 ); 
   }void loop()
{ 
  int aX, aY, aZ, aSqrt, gX, gY, gZ, mDirection, mX, mY, mZ;
  Wire.begin();
  mySensor.setWire(&Wire);
 
  mySensor.beginAccel();
  mySensor.beginGyro();
  mySensor.beginMag();// You can set your own offset for mag values
  // mySensor.magXOffset = -50;
  // mySensor.magYOffset = -55;
  // mySensor.magZOffset = -10;mySensor.accelUpdate();
  aX = mySensor.accelX();
  aY = mySensor.accelY();
  aZ = mySensor.accelZ();
  aSqrt = mySensor.accelSqrt();
  Serial.print("aX:");
  Serial.println(aX);
  Serial.print("aY:");
  Serial.println(aY);
  Serial.print("aZ:");
  Serial.println(aZ);
  Serial.print("aSqrt:");
  Serial.println(aSqrt);mySensor.gyroUpdate();
  gX = mySensor.gyroX();
  gY = mySensor.gyroY();
  gZ = mySensor.gyroZ();
  Serial.print("gX:");
  Serial.println(gX);
  Serial.print("gY:");
  Serial.println(gY);
  Serial.print("gZ:");
  Serial.println(gZ);mySensor.magUpdate();
  mX = mySensor.magX();
  mY = mySensor.magY();
  mZ = mySensor.magZ();
  mDirection = mySensor.magHorizDirection();
  Serial.print("mX:");
  Serial.println(mX);
  Serial.print("mY:");
  Serial.println(mY);
  Serial.print("mZ:");
  Serial.println(mZ);
  Serial.print("mDirection:");
  Serial.println(mDirection);
  
  Wire.end();delay(1000);
  txNumber += 0.01;
  sprintf(txpacket,"%s","Value Aix = ");  //start a package
  sprintf(txpacket+strlen(txpacket),"gX = %d / gY = %d / gZ = %d ",gX,gY,gZ); //add to the end of package
  
  DoubleToString(txpacket,txNumber,3);     //add to the end of package
  
  turnOnRGB(COLOR_SEND,0); //change rgb colorSerial.printf("\r\nsending packet \"%s\" , length %d\r\n",txpacket, strlen(txpacket));Radio.Send( (uint8_t *)txpacket, strlen(txpacket) ); //send the package out 
}/**
  * @brief  Double To String
  * @param  str: Array or pointer for storing strings
  * @param  double_num: Number to be converted
  * @param  len: Fractional length to keep
  * @retval None
  */
void  DoubleToString( char *str, double double_num,unsigned int len) { 
  double fractpart, intpart;
  fractpart = modf(double_num, &intpart);
  fractpart = fractpart * (pow(10,len));
  sprintf(str + strlen(str),"%d", (int)(intpart)); //Integer part
  sprintf(str + strlen(str), ".%d", (int)(fractpart)); //Decimal part
}