Understanding what Assets mean on the AllThingsTalk platform
Assets are active components that hold value about a measure, either in physical or virtual space.
Most important physical assets are sensors and actuators.
Kind
There are 3 supported asset kinds:
- Sensor provide you with environment data. Examples are temperature or light
- Actuator allow other systems to reach out and act on the world. Examples are motor or LED
- Virtual asset has no link to the physical device, but holds higher-value knowledge, usually calculated as a result of on-cloud processing. Examples are health or consumption
Name
Name uniquely identifies the asset within it’s device. Once you define it, you can’t change it.
An asset with the same name can exist on two different devices. For example if you have 5 weather station devices, they might all have their own temperature assets.
Profile
The profile field describes the type of data being measured by the asset. Both simple types like integer as well as more complex and custom object data types are possible. Read more about profiles.
Example
When modelling a weather station, one of the things you might want to represent measured temperature as a numeric value.
To do this, you will need to create a sensor called temperature, using the number profile as {"type": "number", "unit": "°C"} - and update values with asset states such as 23.1°C or 18°C.
LoRaWAN Container considerations
Asset naming
For LoRaWAN, the name of your asset has to match the integer number of the data container it will be used for.
An overview of these numbers and their corresponding data containers can be found here.
Asset name matching the container definition
Asset payload
The data rate and maximum packet size for the application payload roughly depend on the distance to the nearest gateway and the type of data to be sent, and are also defined in the specification for each region.
For the European 863-870MHz band, the application packet size varies between 51 bytes for the slowest data rate, and 222 bytes for faster rates.
Beware that the LoRaWAN protocol adds at least 13 bytes to the application payload.
To facilitate your LoRa project, we have created a LoRAWAN library which takes of the data rate and constructing the application payload and converting back the payload message into understandable information for AllThingsTalk Maker. The LoRaWAN library supports a container structure for various type of sensors to make it easy for you to write your first programs.
A simple instruction such as Device.Send(val, LOUDNESS_SENSOR); will send data towards AllThinsgTalk Maker representing data for a loudness sensor.
More information about the container structure can be found here.
To visualize the sensor data in an asset, specify the container number in the Name field when creating the asset.