IBM watson IoT platform-Hex data - ibm-cloud

Question

My question is about connecting loriot network server to the IBM Watson IoT Platform.
I have managed to connect loriot backend with the Watson IoT Platform and see some data coming through. However, the data are in a hexadecimal format. Any idea on how I can convert this hex data to be human readable?

Answer 1

If the data coming through to the Watson IoT Platform is in JSON format, but contains properties whose values are in hex, you can use the Data Management capabilities to convert the data in these events to Device State. The expression language used in the property mapping expressions includes an $unpack function that can be used to convert strings and hex octets to numeric values. When used in conjunction with the $substring function, you can extract specific strings from a large hex value and convert it to a number.
As an example, say you had the following inbound event:
{
"propertyA": "valueA",
"propertyB": "valueB",
"data": "3b45940201000000010e4601"
}
... you could map values to properties on the device state using mapping expressions similar to the following:
$unpack($substring($event.data, 0, 8), "l32f")
$unpack($substring($event.data, 8, 2), "l8")
$unpack($substring($event.data, 10, 8), "l32")
The corresponding output of the three expressions above is:
2.1786381830505485E-37
1
16777216
The Data Management capabilities are documented here:
https://console.bluemix.net/docs/services/IoT/GA_information_management/ga_im_device_twin.html#device_twins