Air Quality Station with BMX280 and PMS7003

Description

The program sends periodically LoRaWAN frames with environmental measurements from Bosch BMX280 and Plantower PMS7003 sensors.

Wiring

Build

Build the firmware

export RIOTBASE=~/github/RIOT-OS/RIOT
make

Flashing

Connect the LoRa E5 Mini pins to the STLink flasher

Pin 1: VDD_TARGET (VDD from application) --> NC
Pin 2: SWCLK (clock)                     --> Pin DLK (Yellow)
Pin 3: GND (ground)                      --> Pin GND (Black)
Pin 4: SWDIO (SWD data input/output)     --> Pin DIO (Blue)
Pin 5: NRST (RESET of target STM32)      --> NC

Check steps 7 and 8 in the wiki. Step 7. Open STM32CubeProgrammer, connect ST-LINK to your PC, hold RESET Button of your Device, then click Connect and release RESET Button: Step 8. Make sure the Read Out Protection is AA, if it is shown as BB, select AA and click Apply:

Flash with OpenOCD

Build and flash the firmware

export RIOTBASE=~/github/RIOT-OS/RIOT
make flash-only

Remark: The version of openocd should be 0.11.0+

Console

Open the serial console of the LoRa E5 board

brew install tio
tio -L
tio -b 115200 -m INLCRNL /dev/tty.usbserial-142xxx

or

make term

or

minicom -s

Setting DEVEUI APPEUI APPKEY

By default, the DevEUI, the AppEUI and the AppKey are forged using the CPU ID of the MCU. However, you can set the DevEUI, the AppEUI and the AppKey of the LoRaWAN endpoint into the main.c.

Optional : Configure the following parameters into the program file main.c : FIRST_TX_PERIOD, TX_PERIOD, DR_INIT, ADR_ON, DEBUG_ON and SECRET.

make SECRET=cafebabe02ffffffcafebabe02000001 binfile

The AppKey can be recovered from the DevEUI (displayed at startup) and the SECRET (flashed into the firmware) with the command lines below:

SECRET=cafebabe02000001cafebabe02ffffff                                         
DevEUI=33323431007f1234                                                         
AppEUI=33323431ffffffff                                                        
SHA=$(echo -n $DevEUI$AppEUI$SECRET | xxd -r -p | shasum -b | awk '{print $1}')
AppKey="${SHA:0:32}"
echo $AppKey

The DevEUI, the AppEUI and the AppKey can be set by fixing DEVEUI APPEUI APPKEY into the make command

make DEVEUI=33323431007f1234 APPEUI=33323431ffffffff APPKEY=f482a62f0f1234ac960882a2e25f971b binfile

Downlink

The application can send a downlink message to the endpoint throught your network server.

Downlink payload can be used for

• sending an ASCII message (port = 1)
• setting the tx period of the data (port = 3)
• setting the realtime clock of the endpoint (port = 202)
• rebooting the board immedialy (port = 64)
• rebooting the board after 1 minute (port = 65)
• rebooting the board after 1 hour (port = 66)

Remark: Chirpstack implements the App Clock Sync Specification. The synchronization is done at the LNS level.

Payload format

Uplink

• byte 0: error flags : bit0 if error on BMX280, bit1 if error on PMS7003

If there is no error with BMX280

• byte 1-2 : temperature
• byte 3-4 : pressure
• byte 5-6 : humidity

If there is no error with PMS7003

• byte 7-8 : pm1_0Standard

• byte 9-10 : pm2_5Standard

• byte 10-11 : pm10Standard

• byte 12_13 : pm1_0Atmospheric

• byte 14_15 : pm2_5Atmospheric

• byte 16_17 : pm10Atmospheric

• byte 18_19 : particuleGT0_3

• byte 20_21 : particuleGT0_5

• byte 22_23 : particuleGT1_0

• byte 24_25 : particuleGT2_5

• byte 26_27 : particuleGT10

Javascript decoder for main LNS is codec/decoder.js

TODO

• add GPIO for resetting the PMS7003 (pin RST) : PA9 or PB10
• fix RTC sync

Misc

Basic test

cd ~/github/RIOT-OS/RIOT
cd tests/pkg_semtech-loramac
BOARD=lora-e5-dev LORA_DRIVER=sx126x_stm32wl gmake -j 16 clean flash

Debugging semtech-loramac stack

Set #define ENABLE_DEBUG 1 into the files ~/github/RIOT-OS/RIOT/pkg/semtech-loramac/contrib/semtech_loramac*.c