ESP32-PaxCounter/docs/payloadformat.md
2022-11-20 19:15:53 +01:00

4.5 KiB

Payload format

You can select different payload formats in paxcounter.conf:

  • Plain uses big endian format and generates json fields, e.g. useful for TTN console

  • Packed uses little endian format and generates json fields

  • CayenneLPP generates MyDevices Cayenne readable fields

!!! danger "Decrepated information from the things network v2"

If you're using [TheThingsNetwork](https://www.thethingsnetwork.org/) (TTN) you may want to use a payload converter. Go to TTN Console - Application - Payload Formats and paste the code example below in tabs Decoder and Converter. This way your MQTT application can parse the fields `pax`, `ble` and `wifi`.

To add your device to myDevices Cayenne platform select "Cayenne-LPP" from Lora device list and use the CayenneLPP payload encoder.

To track a paxcounter device with on board GPS and at the same time contribute to TTN coverage mapping, you simply activate the [TTNmapper integration](https://www.thethingsnetwork.org/docs/applications/ttnmapper/) in TTN Console. Both formats *plain* and *packed* generate the fields `latitude`, `longitude` and `hdop` required by ttnmapper. Important: set TTN mapper port filter to '4' (paxcounter GPS Port).

Hereafter described is the default plain format, which uses MSB bit numbering. Under /TTN in this repository you find some ready-to-go decoders which you may copy to your TTN console:

plain_decoder.js | plain_converter.js | packed_decoder.js | packed_converter.js

Port #1: Paxcount data

byte 1-2:		Number of unique devices, seen on Wifi [00 00 if Wifi scan disabled]
byte 3-4:		Number of unique devices, seen on Bluetooth [ommited if BT scan disabled]

Port #2: Device status query result

byte 1-2:		Battery or USB Voltage [mV], 0 if no battery probe
byte 3-10:		Uptime [seconds]
byte 11: 		CPU temperature [°C]
bytes 12-15:	Free RAM [bytes]
byte 16:		Last CPU core 0 reset reason
bytes 17-20:	Number of restarts since last power cycle

Port #3: Device configuration query result

byte 1:		Lora DR (0..15, see rcommand 0x05) [default 5]
byte 2:		Lora TXpower (2..15) [default 15]
byte 3:		Lora ADR (1=on, 0=off) [default 1]
byte 4:		Screensaver status (1=on, 0=off) [default 0]
byte 5:		Display status (1=on, 0=off) [default 0]
byte 6:		Counter mode (0=cyclic unconfirmed, 1=cumulative, 2=cyclic confirmed) [default 0]
bytes 7-8:	RSSI limiter threshold value (negative, MSB) [default 0]
byte 9:		Scan and send cycle in seconds/2 (0..255) [default 120]
byte 10:	Wifi channel hopping interval in seconds/100 (0..255), 0 means no hopping [default 50]
byte 11:	Bluetooth channel switch interval in seconds/100 (0..255) [default 10]
byte 12:	Bluetooth scanner status (1=on, 0=0ff) [default 1]
byte 13:	Wifi antenna switch (0=internal, 1=external) [default 0]
byte 14:	0 (reserved)
byte 15:	RGB LED luminosity (0..100 %) [default 30]
byte 16:	Payloadmask (Bitmask, 0..255, see rcommand 0x14)
byte 17:	0 (reserved)
bytes 18-28:	Software version (ASCII format, terminating with zero)

Port #4: GPS data (only if device has fature GPS, and GPS data is enabled and GPS has a fix)

bytes 1-4:		Latitude
bytes 5-8:		Longitude
byte 9:			Number of satellites
bytes 10-11:	HDOP
bytes 12-13:	Altitude [meter]

Port #5: Button pressed alarm

byte 1:		static value 0x01

Port #6: (unused)

Port #7: Environmental sensor data (only if device has feature BME)

bytes 1-2:	Temperature [°C]
bytes 3-4:	Pressure [hPa]
bytes 5-6:	Humidity [%]
bytes 7-8:	Indoor air quality index (0..500), see below

Indoor air quality classification:
0-50		good
51-100		average
101-150 	little bad
151-200 	bad
201-300 	worse
301-500 	very bad

Port #8: Battery voltage data (only if device has feature BATT)

bytes 1-2:	Battery or USB Voltage [mV], 0 if no battery probe

Port #9: Time/Date

bytes 1-4:	board's local time/date in UNIX epoch (number of seconds that have elapsed since January 1, 1970 (midnight UTC/GMT), not counting leap seconds)

Ports #10, #11, #12: User sensor data

Format is specified by user in function `sensor_read(uint8_t sensor)`, see `src/sensor.cpp`.