Using nrf9160-DK and nrfCloud - Control GPIO from the nrfCloud

Question

There are many examples available where nrf9160 is reporting data to nrfcloud or some other service. However I cannot find an example where an external application over MQTT or nrfcloud REST API would perform an activity. I am using nrf9160DK as my dev board, I will port the code to Feather later on. 
 I guess I found a piece of code where this kind of connection is handled(multi service mqtt example), connection.c -> cloud_event_handler function -> case NRF_CLOUD_EVT_RX_DATA_GENERAL. 
 Somehow I got lost where to continue next. I guess I would know how to create another sensor(just recreate temperature example), however I would like to turn on/off a GPIO pin. I know how to any retrieve data from nrfcloud with Insomnia by using GET method. But I dont know how would I handle POST command in this case. 
 It seems that legacy version of asset tracker had one example with Thingy:91, but it is not available anymore(or at least I cannot find it). 
 Thanks, 
 Robert

justin_nordic · Accepted Answer

You can use the SendDeviceMessage endpoint to send data to your device. The topic field in the message needs to be a topic your device is subscribed to. So if you are using a current version of the nrf_cloud firmware library (as the MQTT multi-service sample does), you can use the c2d/r topic, which would be formatted in your message as follows: "d/ /c2d/r" An example curl command: curl --location ' https://api.nrfcloud.com/v1/devices/ /messages' \ --header 'Content-Type: application/json' \ --header 'Authorization: Bearer ' \ --data '{"message":{"test" : "hello world"}, "topic": "d/ /c2d/r"}'

Using nrf9160-DK and nrfCloud - Control GPIO from the nrfCloud

Top Replies