Almere, The Netherlands

Oscar,
Node 02013D42 is my node, not Arjan's. It is a MicroChip Technology Mote.
The default application sends the light intensity and temperature in the payload: 5 ASCII characters for light (01023 full scale) and 3 ASCII characters for temperature (e.g. 023).
For testing purposes, my node is also remotely controllable, providing the ability to send anything you want. So in the TTN logs/MQTT broker, you will find many different payload formats that others have used to test their back-ends.