How To Connect Your First LoRa Device ( STM32L072CZ Microcontroller ) Using B-L072Z-LRWAN1 And The Shield X-NUCLEO-IKS01A2 From STMicroelectronics

LoRa Device ( B-L072Z-LRWAN1 + X-NUCLEO-IKS01A2 )

                                                  

 

Hello , In our Previous Articles Entitled " How To Connect Your First LoRa Gateway " We Built our First LoRa Gateway and Today we Will Connect Our first LoRa Device To our Gateway Step by Step.

Link to Our Previous Article : Link 

 ** Let's Start our Project ** 

Today i will show you guys How to Setup , Build and Connect Your first Device step by step .
First of all we need to buy some component for our Project so :

Hardware needed :

 - B-L072Z-LRWAN1 Board From STMicroelectronics

 - X-NUCLEO-IKS01A2 From STMicroelectronics  

 - Our LoRa Gateway 

Software needed :

- IAR Embedded Workbench

- STM32 ST-LINK utility 

Link To Download it : Link 

- LoRaWAN software expansion for STM32Cube

Link To Download it : Link 

First of all , Let's Talk about The Features of Each Board  :

- B-L072Z-LRWAN1 :

This Board contain an STM32L072CZ Microcontroller , This Microcontroller Belongs to the category Of LOW Power ( LP : Low Power ) and 32 MHz max CPU frequency . Also Our Board Contain an SX1276 Transceiver . The transceiver features the LoRa long-range modem, providing ultra-long-range spread spectrum communication and high interference immunity, minimizing current consumption . Our Board is Based on : 

The CMWX1ZZABZ-091 LoRa/Sigfox™ module (Murata) :

• - 860-930MHz LPWA Module
• - Chipset: Semtech (SX1276) + STM (STM32L)
• - Modulation: FSK, OOK and LoRa Modulation

• - Small form factor LoRaWAN module
• - MCU Chipset: STM32L0 Series
• - CPU: ARM Cortex-M0+
• - Peripheral Interfaces: I2C, UART, USB, SPI
• - Pre-certified radio regulatory approvals: 868 & 915 MHz spectrum

Finally , This Board is amazing , it can Be Connect Like a Sigfox Device or Like a LoRa Device.

* All The Technical Documentation you can Check it Here : Link *

- X-NUCLEO-IKS01A2 :

The X-NUCLEO-IKS01A2 is a motion MEMS and environmental sensor evaluation board system :

- LSM6DSL:

MEMS 3D accelerometer (±2/±4/±8/±16 g) + 3D gyroscope (±125/±245/±500/±1000/±2000 dps)

- LSM303AGR:

MEMS 3D magnetometer (±50 gauss) + MEMS 3D accelerometer (±2/±4/±8/±16 g)

- LPS22HB:

MEMS pressure sensor, 260-1260 hPa absolute digital output barometer

- HTS221:

Capacitive digital relative humidity and temperature

- DIL 24-pin:

Socket available for additional MEMS adapters and other sensors (UV index)

* All The Technical Documentation you can Check it Here : Link *

Our LoRaWAN Device Support Three Type of Class :

- Class A ( Bi-Directional End Devices ) :

• End-devices of Class A allow for bi-directional communications whereby each end-device's uplink transmission is followed by two short downlink receive windows.      

- Class B ( Bi-Directional End-Devices with scheduled receive slots ) :

• In addition to the Class A random receive windows, Class B devices open extra receive windows at scheduled times.

PNG : Ping Slots
BCN : Beacon ( Beacon Period )

What's Beacon ? 
In Class B, the gateway broadcasts a periodic beacon every 128s . the beacon transmission is protected by a reserved period Called Beacon Period and it took 5.12s .
*) This is An Exemple for the Beacon ( BCN ) :

What's Ping Slots ?
 Between two beacons, each end-device opens N reception slots called ping slots .

What's Ping Period ?
The ping period is the delay between two ping slots, and is constant. The offset between the beacon
and the first ping slot is pseudo-randomly chosen after each beacon by each end-device .

In The Link Bellow , You Can Check and See More Information About The Beacon Period ( BCN ) and Ping Slots ( PNG ) and Also More information About LoRaWAN Class B .

Link 

- Class C ( Bi-Directional End-Devices with maximum receive slots ) :

• End-devices of Class C have nearly continuously open receive windows, only closed when transmitting.

Diagram Explanatory for the three class of LoRaWAN

LoRaWAN Class A :

Advantages : 

- Lowest power consumption = longest battery life

Disadvantages :

- Long latency

Example : 

- Battery powered sensors

LoRaWAN Class B :

Advantages : 

- Deterministic latency

Disadvantages :

- Higher power consumption

Example : 

- Battery powered actuator end-device

LoRaWAN Class C :

Advantages : 

- Lowest receive latency

- End-device has continuous receive window

Disadvantages :

- Highest power consumption (expect end-device to be mains powered)

Example : 

- Mains power low-latency actuator end-device

Now, You Know which Class of LoRaWAN will be used , We will Just Send The Values of Our Sensors Motion and Battery Level From our Device To The Gateway. So ....... Yes is the Class A .

LoRa Architecture 

Steps : 

1) Creating Your device on The Things Network :

 - Go To https://www.thethingsnetwork.org and Login to Your Account .

 - Go To Console .

- Click on Applications .

 - Access your application on The Things Network .

- Select Devices and click Register Device .

- Create Your Device ID to indentify your device on the network. On Device EUI, click on random      button to generate it, then click Register.

- Our device was created on the network . The Activation Method is OTAA by default, We will click on Settings to change it.

- Select the Activation Method ABP and disable Frame Counter Checks The Device Address, Network Session Key and App Session Key will be generated Automatically. Click Save.

 What's OTAA Method ? 

What's ABP Method ? 

Difference Between OTAA and ABP ? 

2) Configuring B-L072Z-LRWAN1 Development Board :

- Go To The File That you Downloaded Named ( I-CUBE-LRWAN ) and Extract it .
- We Need This Project Example ( End_Node ) Follow my steps :
        1- Click on STM32CubeExpansion_LRWAN_V1.2.1 ( The Extracted Folder )

File Location ( Path ) :

The Exact Location ( Path )  :


C:\The_Location_Of_I_CUBE_LRWAN_Folder\STM32CubeExpansion_LRWAN_V1.2.1\Projects\B-L072Z-LRWAN1\Applications\LoRa\End_Node\EWARM


- Open IAR Embedded Workbench
- Click On Project Then Click on Add Existing Project 

- Choose Lora.ewp

- Now , Right Click on " LoRa - mlm32l07x01 " 

Add the define "X_NUCLEO_IKS01A2" on Defined Symbols Then Click on OK

Or Copy and Paste :

STM32L072xx

USE_B_L072Z_LRWAN1

USE_HAL_DRIVER

 REGION_EU868

 X_NUCLEO_IKS01A2 

- Now , We will Make Some Change . Go To : Projects\End_Node\main.c\Commissioning.h.

In The Commissioning.h File :

- Do Ctrl + f For Fast Search 

Changes in Commissioning.h File :

1- #define OVER_THE_AIR_ACTIVATION         0

2- #define STATIC_DEVICE_EUI                          1

3- #define STATIC_DEVICE_ADDRESS              1

- Open the "Device Overview" of your device on the Things Network. Use the information to change lines as the following images . 

Changes The Informations in Red Box with Your Informations Fron TheThingsNetwork :

- LORAWAN_DEVICE_EUI ------------ with ----------- ( LoRaWAN Device EUI )
- LORAWAN_JOIN_EUI ------------ with ----------- ( LoRaWAN Application EUI )
- LORAWAN_APP_KEY ------------ with ----------- ( LoRaWAN App Session Key )
        

- LORAWAN_DEVICE_ADDRESS ------------ with ----------- ( LoRaWAN Device Adress )
- LORAWAN_F_NWK_S_INT_KEY ------------ with ----------- ( Network Session Key )
- LORAWAN_S_NWK_S_INT_KEY ------------ with ----------- ( Network Session Key )
- LORAWAN_NWK_S_ENC_KEY ------------ with ----------- ( Network Session Key )

- LORAWAN_APP_S_KEY ------------ with ----------- ( LoRaWAN App Session Key )

Attention !

Choose Hex Format For :

- LoRaWAN Device EUI

- LoRaWAN Application EUI

- LoRaWAN App Session Key

- Network Session Key

Follow images :

We Completed our Modification in This File ( Commissioning.h ) . So We Save our Modification .

- Next we Have Some Modification in An other File . This File Named ( hw_conf.h ) Go To :       Projects\End_Node\main.c\hw_conf.h .(See The Picture Below)

Remove the comments from :


- #define   DEBUG

- #define   LOW_POWER_DISABLE

- #define   SENSOR_ENABLED

We Completed our Modification in This File ( hw_conf.h ) . So We Save our Modification

- Now we will Save All , Build and Download our Code .

My Results : 

3) Make a Decoder for Your Payload Format : 

- You must be receiving a hexadecimal payload on The Things Network. So , Now We Will Simplify The Understanding of This Data Let's Begin .

Copy and Paste The Code Below in The Payload Formats :

function Decoder(bytes, port) { 
 // Decode an uplink message from a buffer 
 // (array) of bytes to an object of fields. 
 var decoded = {}; 
 // Decode bytes to int 
 var batteryInt = bytes[7] 
 var humidityInt = (bytes[5] << 8) | bytes[6]; 
 var pressureInt = (bytes[1] << 8) | bytes[2]; 
 var temperatureInt = (bytes[3] << 8) | bytes[4]; 
 // Decode int to float 
 decoded.battery = (batteryInt*100)/254        // Battery in % 
 decoded.humidity = humidityInt / 10;          // Humidity in % 
 decoded.pressure = pressureInt / 10;          // Pressue in hPa 
 decoded.temperature = temperatureInt / 100;   // Temperature in °C 
 return decoded; 

} 

Data Received :