How do I decode a sensor's Supervisory Message?

            The wireless sensors will send a periodic supervisory message so that a backend system can verify that the device is still alive and to report error conditions. 
            The supervisory message also contains a payload that contains the status (current) of the sensor.

            Supervisory Message: 0x01
                  Bytes Description
                  0         Supervisory error codes
                  1                 Current Sensor State (different for each sensor type)
                  2         Battery level

                   The current sensor state (byte 1 of the supervisory message) is defined by the individual data sheets. 
                   Byte 2 is used if there is a second sensor state to report.
                   The battery level (byte 3 of the supervisory message) is a two-digit battery voltage.
                   It is designed to be human-readable. For example, if the battery voltage is 2.9V, byte 3 would be 0x29.

            Supervisory Error Codes: Bit Definitions
                  Bits                   Description
                  7:5                Not used
                  4                Tamper detected since last reset
                  3                Current tamper state
                  2                Error with last downlink
                  1                        Battery Low (under 2.75V)
                  0                Radio Comm Error. Communication with the integrated radio has failed and device has been reset.

            Example of Supervisory Message for a Contact Sensor:

            1 0 01 08 01 30

            1 Protocol Version (currently always 0x1)
                    0      Packet Counter (increments by 1 each message and wraps from 0xF to 0x0)
                    01 Message Type Code (Supervisory Message = 0x01)
            08 Error Codes (Current Tamper State = True / Untampered)
            01 Current Sensor State (Contacts Open = 0x01)
            30 Current Battery Level (3.0V = 0x30)

            See Also: 
            Updated: 5 days ago
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