cayenne.lpp.decode action

Action

The Cayenne LPP (Low Power Payload) provides a convenient way to send data over LPWAN (Low-power, wide-area networks). The LPP protocol https://github.com/myDevicesIoT/cayenne-docs/blob/master/docs/allows for compact binary packets to be sent and decoded without knowledge about the data structure.

The Cayenne LPP enables the devices to send different sensor data in different frames. Each sensor data is prefixed with two bytes that contain the Data Channel and Data Type information.

The format of the data is as follows:


Data1 Channel	Data1 Type	Data	Data2 Channel	Data2 Type	Data	...
1 Byte	1 Byte	N Bytes	1 Byte	1 Byte	N Bytes	...

Data Channel: Uniquely identifies each sensor in the device across frames. For example, Temperature sensor
Data Type: Identifies the data type in the frame. For example, Temperature

Each data type uses one or more bytes to send the data according:


Type	IPSO	LPP	Hex	Data Size	Data Resolution per bit
Digital Input	3200	0	0	1	1
Digital Output	3201	1	1	1	1
Analog Input	3202	2	2	2	0.01 Signed
Analog Output	3203	3	3	2	0.01 Signed
Illuminance Sensor	3301	101	65	2	1 Lux Unsigned MSB
Presence Sensor	3302	102	66	1	1
Temperature Sensor	3303	103	67	2	0.1 °C Signed MSB
Humidity Sensor	3304	104	68	1	0.5 % Unsigned
Accelerometer	3313	113	71	6	0.001 G Signed MSB per axis
Barometer	3315	115	73	2	0.1 hPa Unsigned MSB
Gyrometer	3334	134	86	6	0.01 °/s Signed MSB per axis
GPS Location	3336	136	88	9	Latitude: 0.0001 ° Signed MSB Longitude: 0.0001 ° Signed MSB Altitude: 0.01 meter Signed MSB

Examples

For example, Device with temperature and acceleration sensors:

Table 1. Device with 2 temperature sensors
Payload (Hex)	03 67 01 10 05 67 00 FF
Data Channel	Type	Value
03 ⇒ 3	67 ⇒Temperature	0110 = 272 ⇒ 27.2°C
05 ⇒ 5	67 ⇒Temperature	00FF = 255 ⇒ 25.5°C

Table 2. Device with temperature and acceleration sensors - Frame N
Payload (Hex)	01 67 FF D7
Data Channel	Type	Value
01 ⇒ 1	67 ⇒Temperature	FFD7 = -41 ⇒ -4.1°C

Table 3. Device with temperature and acceleration sensors - Frame N+1
Payload (Hex)	06 71 04 D2 FB 2E 00 00
Data Channel	Type	Value
06 ⇒ 6	71 ⇒Accelerometer	X: 04D2 = +1234 ⇒ +1.234G Y: FB2E = -1234 ⇒ -1.234G Z: 0000 = 0 ⇒ 0G

Table 4. Device with GPS
Payload (Hex)	01 88 06 76 5f f2 96 0a 00 03 e8
Data Channel	Type	Value
01 ⇒ 1	88 ⇒GPS	Latitude: 06765f ⇒ 42.3519 Longitude: F2960a ⇒ -87.9094 Altitude: 0003E8 ⇒ 10 meters

Action

On the Adding trigger page, under Binary, drag cayenne.lpp.decode to the canvas.

Canvas

When dragged onto the canvas, the appearance of the action is a rectangle with two routing points.

The left routing point (red) is the failure route. This route will be taken if there is an error during execution.

The right routing point (green) is the success route. This route will be taken if action executes successfully.

Form

Parameters


Name	Type	Required	Description
Input	String	Yes	The cayenne.lpp string to be converted.

Action variable

This action returns multiple values for each channel sent in the packet. In the examples below, Y is the channel number that is received.


Name	Type	Description
$(action.X.channels.Y.name)	String	The name of the sensor type, this will be a human-readable name such as Analog Input or Temperature Sensor.
$(action.X.channels.Y.key)	String	The string key for the sensor type, this will be ideal as a programmatic key such as analogIn or temperature.
$(action.X.channels.Y.value)	Varies	For numerical sensor types, this value will be a floating point value. For accelerometer and gyrometer, the result will be an object with x, y, and z values. For GPS, the result will be an object with lat, lng, and alt fields.