Sending Measurements via MQTT

In this article we will go over how to send individual measurements via MQTT protocol.
If you have many measurements to send in high frequency or if you prefer to send messages in bulk, please read more about how to send measurements in waveform.

To send a measurement or the current device status, you first need to obtain the appropriate topics from the “environmentData” named shadow.

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Note

The clientId in the following topics is configured in the device during the activation stage. See Direct Device Connection

Register to the following topic:

$aws/things/<clientId>/shadow/name/environmentData/get/accepted

Then publish an empty JSON message to the following topic:

$aws/things/<clientId>/shadow/name/environmentData/get

You will receive the current “environmentData” shadow content, for example:

{
   "state":{
      "desired":{
         "topics":{
            "MEASUREMENT":{
               "publish":"<clientId>/from-device/measurement"
            },
            "STATUS":{
               "subscribe":"<clientId>/to-device/status",
               "publish":"<clientId>/from-device/status"
            }
         }
      },
      "delta":{
         "topics":{
            "MEASUREMENT":{
               "publish":"<clientId>/from-device/measurement"
            },
            "STATUS":{
               "subscribe":"<clientId>/to-device/status",
               "publish":"<clientId>/from-device/status"
            }
         }
      }
   }
}

• Read the “MEASUREMENT.publish” value from the received JSON and use it as the topic to publish the measurement to.
• Read the “STATUS.publish” value from the received JSON and use it as the topic to publish the statuses to.
• Read the “STATUS.subscribe” value from the received JSON and subscribe to it to get status update requests from BioT.

Sending measurements

Use the following JSON format to send a measurement:

{
   "metadata":{
      "timestamp":1641985478161,
      "context":"ewogICJwYXRpZW50SWQiOiAiZDU3MzhkZjYtMGRlZS00YTY1LTk0MzktODg5ZTE3YTM2MjM3IiwKICAic2Vzc2lvbklkIjogIjBhYWVjYTRmLTMxOGUtNDg5MS1hOWY1LWY3YTBiNzkyMjVkNCIsCiAgIm93bmVyT3JnYW5pemF0aW9uSWQiOiAiYWUwNmI1MWYtOTEyOS00NDg3LThiODgtN2MwNWIwMDcxMmRhIgp9"
   },
   "data":{
      "hr":"97",
      "spo2":"92"
   }
}

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Sending historical measurements

In some cases historical measurements shall be uploaded by the device. Historical measurements are defined as measurements that their timestamp is older than 1 day from the current timestamp This can happen, for example, when the device that was offline for a while, uploads it's locally save measurement to the cloud.

In this case it will take up to 6 hours for the data to be added to the database and be searchable from the historical view.

If you need to send measurements older then a single day that need to be logged in immediately, please contact us and we will update the platform to fit your exact needs.