Tutorial: LoRa

This page shows the tutorial for LoRa experiments.

Platform and programming environments

Arduino + Lora

• Lora is a wireless communication module，we also need a MCU to contral it like Raspberry Pi（树莓派）、Arduino and so on. (Here we choose Arduino).
• More about Arduino
• Lora

Configuration Environment

Lora通信实例

• 使用Arduino进行Lora开发，首先需要环境配置：

1. 下载和安装Arduino IDE [Arduino下载]
2. 在IDE中添加开发板 我们要在IDE上编写代码烧录到板子上运行，首先需要把板子信息加载到IDE里面，这样，IDE才能识别到开发板。以我们使用的Dragino开发板为例：

具体步骤：
 在PC上打开IDE --> 点击File --> preference-->在Additional Boards Manager URLs里添加以下URL：http://www.dragino.com/downloads/downloads/YunShield/package_dragino_yun_test_index.json
 转到tools --> Boards --> Boards Manager,找到Dragino信息并安装它
 这样，我们的Dragino开发板就成功的关联到了IDE里面，可以打开IDE --> Tools的开发板，就能找到Dragino

• 用数据线将开发板连接到电脑，从IDE选择开发板，然后选择的Tools选择端口(开发板连接的端口)。下面是Lora通信的示例代码：

Client：

#include <SPI.h>
#include <RH_RF95.h>

RH_RF95 rf95;
float frequency = 433.0;

void setup() 
{
 Serial.begin(9600);
 while (!Serial) ; // Wait for serial port to be available
 Serial.println("Start LoRa Client");
 if (!rf95.init())
   Serial.println("init failed");
 // Setup ISM frequency
 rf95.setFrequency(frequency);
 // Setup Power,dBm
 rf95.setTxPower(18);
 // Setup Spreading Factor (6 ~ 12)
 rf95.setSpreadingFactor(12);
 // Setup BandWidth, option: 7800,10400,15600,20800,31200,41700,62500,125000,250000,500000
 //Lower BandWidth for longer distance.
 rf95.setSignalBandwidth(125000);
 // Setup Coding Rate:5(4/5),6(4/6),7(4/7),8(4/8) 
 rf95.setCodingRate4(5);
}

void loop()
{
 Serial.println("Sending to LoRa Server");
 // Send a message to LoRa Server
 uint8_t data[] = "Hello, this is device 1";
 rf95.send(data, sizeof(data));
 rf95.waitPacketSent();
 // Now wait for a reply
 uint8_t buf[RH_RF95_MAX_MESSAGE_LEN];
 uint8_t len = sizeof(buf);
 delay(1000);  
}

• Server：

#include <SPI.h>
#include <RH_RF95.h>

RH_RF95 rf95;
int led = A2;
float frequency = 433.0;

void setup() 
{
 pinMode(led, OUTPUT);     
 Serial.begin(9600);
 while (!Serial) ; // Wait for serial port to be available
 Serial.println("Start Sketch");
 if (!rf95.init())
   Serial.println("init failed");
 // Setup ISM frequency
 rf95.setFrequency(frequency);
 // Setup Power,dBm
 rf95.setTxPower(13);
 // Defaults BW Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC on
 Serial.print("Listening on frequency: ");
 Serial.println(frequency);
}

void loop()
{
 if (rf95.available())
 {
   // Should be a message for us now   
   uint8_t buf[RH_RF95_MAX_MESSAGE_LEN];
   uint8_t len = sizeof(buf);
   if (rf95.recv(buf, &len))
   {
     digitalWrite(led, HIGH);
     RH_RF95::printBuffer("request: ", buf, len);
     Serial.print("got request: ");
     Serial.println((char*)buf);
     Serial.print("RSSI: ");
     Serial.println(rf95.lastRssi(), DEC);
     
     // Send a reply
     uint8_t data[] = "And hello back to you";
     rf95.send(data, sizeof(data));
     rf95.waitPacketSent();
     Serial.println("Sent a reply");
     digitalWrite(led, LOW);
   }
   else
   {
     Serial.println("recv failed");
   }
 }
}