In the figure above the principal device to device communication with IoT hub can be seen. The goal for this project is to send a message from one device to another device. The Raspberry Pi sends a message to the Philipps Hue when he sees the Raspberry Pi face recognition program. The Philipps Hue receives the message and changes the color according to the recognized person.
This messaging process needs to be done in combination with the IoT Hub. In detail a message from the Raspberry Pi (Device 1) is sent to a custom endpoint of the IoT Hub. This message is stored in a service bus queue or a storage container or something similar and then processed by an azure function or logic app which establishes a connection with the target device (Device 2).
In this project it is possible to create a face recognition with the raspberry pi and when a face gets detected a message is sent to the IoT hub. It’s possible to send messages from the IoT hub to the raspberry pi. But it could not be possible to create a device to message message, even though a message could be stored in a storage container and the logic app could react to this message.