Function Definition

This topic describes how to define functions for a TuyaLink-based product.

Concepts

Device model

The device model construct describes an abstraction of physical devices. It defines the characteristics and behaviors of a type of device that connects to the Tuya IoT Development Platform.

A device model defines an abstract representation of a device as a set of properties, actions, and events, which determines how a connected physical device interacts with the cloud applications.

Standard and custom function

• Standard function: refers to a template library of standard data points (DP). It provides the definition of common features for more than 1,000 product categories.

• Custom function: supports various feature types and data types to help you define custom features as needed.

Prerequisites

You have created at least one TuyaLink-based product.

Procedure

Step 1: Go to function definition

1. Log in to the Tuya IoT Development Platform. Choose a created product and click Continue to Develop.

2. Click the Function Definition tab.

   

Step 2: Add standard functions

Select the desired functions and add them.

Step 3: Add custom functions

If the standard functions cannot address your needs, you can create custom functions.

Three function types are available: property, event, and action. Choose the types that suit your product features to create custom functions.

Click Add in the Custom Functions section.

Select a function type and populate the required fields to create a custom function. The required information varies depending on function types. See the following introduction to fields regarding each function type.

• Property type
  The property type is used to define the continuous and queryable states of a device, which can represent one or several feature parameters. For example, a light bulb might have properties like power state and brightness.

  • DP Name: the name of a custom function.

  • Identifier: the unique identifier of a custom function.

  • Data Type: the data type of a property. Nine data types are available, namely value, string, date, boolean, enum, raw, struct, array, and fault.

    

  Example for property definitions

  Data type	Example
  Value	Take the temperature which ranges from 1°C to 100°C as an example. If the reported data is 36.6°C, The definition is as follows: Data type: Value Value Range: 1 to 1,000 Pitch: 1. The pitch specifies the difference between adjacent values. For example, if the pitch is 1, the valid values will be 0, 1, 2… If the pitch is 3, the valid values will be 0, 3, 6… Scale: 1 Unit: °C The scale is used to transform the data of an integer to a decimal, such as transforming 1 to 0.1. In practice, the functions on the devices control the scale. It is only for parameter definition here.
  String	Take the URL of the image as an example. The definition is as follows: Data type: String Maximum length: 50 bytes
  Date	Take the product update time as an example. The device data is reported and parsed by the timestamp. The definition is as follows: Data type: Date Update time: If the update time is defined as 1638853568, the time can be parsed as 2021-12-07 13:06:08.
  Bool	Take the switch as an example. The switch has two statuses: on and off. The definition is as follows: Data type: Bool True: on False: off
  Enum	Take the run mode as an example. It includes sports mode, personal mode, and team mode. The definition is as follows: Data Type: Enum Enum values: Sport_mode/Personal_mode/Team_mode
  RAW	Take the binary code as an example. It cannot be transmitted in plaintext. Data type: RAW The platform directly transmits the data to the device without any processing.
  Struct	Take geolocation as an example. It is in multiple data types. Data type: struct Add parameter: Add the data type as needed. Longitude: Value Latitude: Value Height: Value Coordinate system: Enum You can add parameters to define all components of geolocation.
  Array	Take the color of lights as an example. The color depends on the data. Data type: Array Element type: Select the element type as needed, such as a value type Maximum elements: 3 The color is usually expressed by the RGB values. You can change the RGB values to show different colors.
  Fault	Take the alert as an example. You can report the specified information according to predefined conditions. Data type: Fault Barrier values: a high temperature, a low temperature, and temperature alerts

• Event type
  The event type is used to report live device alerts to the cloud. The reported data can include one or more output parameters. For example, overheating alerts and fault alerts.

  

• Action type
  The action type applies to complex tasks that are required to return the result to the cloud. The input and output parameters must be specified due to this request-response mechanism. For example, after a door is unlocked, the smart lock will return a message indicating the door is unlocked to the mobile app.

  

With the three function types, you can build a cloud-based model with a complete set of features you want to apply to a physical device. This separates a physical device from the device model so that the hardware and application development can be performed in parallel for a quick development cycle.

Next step

Proceed with device development to register your devices for cloud connectivity.