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WIRELESS, SENSING and TIMING PRODUCTS
5.2 Payload Format
The implemented software is based around the GPS and the MPL3115A2 and the packets payload is
composed of 15 bytes. Of course, this payload is only given as an example and the user is free to change
it or to add further information coming from other sensors: The current payload is composed of:
Byte [0]
>
The first byte of the payload indicates the status of LED3 which is controllable from the LoRaServer. The
server can remotely switch this LED ON or OFF.
Byte [1]
>
Byte [2]
>
Byte 1 and 2 represent the atmospheric pressure in dPa (deci-Pascal) as it is measured through the
MPL3115A2. This value can easily be divided by 10 to get the standard hPa value.
Byte [3]
>
Byte [4]
>
Byte 3 and 4 represent the signed value of the temperature (x 100) as it is measured through the
MPL3115A2. This value can easily be divided by 100 to get the temperature with decimal values
Byte [5]
>
Byte [6]
>
Byte 5 and 6 represent the signed value of the altitude (x 10) as it is measured through the MPL3115A2.
This value can easily be divided by 10 to get the altitude with decimal values. It is important to notice that
the value returned is not calibrated. The MPL3115A2 returns the estimate altitude relative to the
atmospheric pressure. Depending on the measurement condition, the value may be within plus or minus
100m. Please, refer to the component datasheet for more details.
Byte [7]
>
The seventh byte of the payload indicates the status of the battery. The status of the battery is returned
as described in the LoRaMAC specification:
0x00:
0x01 to 0xFE:
0xFF:
Revision 2.0 – July 2014
©2014 Semtech Corporation
Value:
0x00 or 0x01
Value:
MSB of the MPL3115A2 measured atmospheric pressure
Value:
LSB of the MPL3115A2 measured atmospheric pressure
Value:
MSB of the MPL3115A2 measured Temperature
Value:
LSB of the MPL3115A2 measured Temperature
Value:
MSB of the MPL3115A2 measured Altitude
Value:
LSB of the MPL3115A2 measured Altitude
Value:
0x00 to 0xFF
The device is connected to an external power source
The battery level, 1 being the minimum and 254 the maximum.
This measurement is a linearized discharge function of the battery and is thus
battery dependent
The LoRaMote was not able to read the battery level
Page 17 of 23
LoRaMote
USER GUIDE
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