WiFi ThingSpeak Read

Read data stored in a ThingSpeak channel on wireless network

Add-On Required: This feature requires the Simulink Support Package for Arduino Hardware add-on.

• 

Libraries:
Simulink Support Package for Arduino Hardware / WiFi

Description

Use the WiFi ThingSpeak Read block to retrieve data from the Internet of Things website by using ThingSpeak™ on a wireless network to download the data to your Arduino^® board.

ThingSpeak is an application platform that you can use for the Internet of Things. You can build an application around data that is collected by sensors. ThingSpeak includes real-time data collection, data processing, visualizations, apps, and plugins.

You can see the ThingSpeak server response to a data download request by selecting the Print diagnostic messages option. This option has no effect when you use External mode, Serial Transmit, or Serial Receive blocks that use port 0.

For more information on how to use ThingSpeak, see ThingSpeak Apps, Plugins, and Tutorials.

Supported Hardware

This table lists the properties of the hardware that the Arduino board supports for the WiFi ThingSpeak Read block.

Target Hardware	Receive Limit (Number of Bytes)
Wi-Fi® Shield	64 bytes
Arduino MKR1000, Arduino MKR Wi-Fi 1010, Arduino Nano 33 IoT, Arduino compatible ESP32 – WROOM, Arduino compatible ESP32 – WROVER	1400 bytes

Note

Using ESP8266 chip for Wi-Fi connectivity does not support deploying WiFi ThingSpeak Read block on an Arduino board.

Ports

Output

fieldn — Data read from nth field of ThingSpeak channel

[1 x N] vector, where N ranges from [1 to 8]

The block outputs the data read from the nth field in the ThingSpeak channel at each time step. The number of data channels at the block output depends on the number of fields that you enter in the Fields to read parameter. For example, if you set the Fields to read parameter to [1 4 5], the block enables three output ports with port names field1, field4, and field5. If the data received from the channel is null, the block outputs 0.

Data Types: single

status — ThingSpeak server response for each read request

scalar

The block outputs the ThingSpeak server response for the read request at each time step. The response is received as an HTTP status code. An HTTP status code of 200 indicates that the read request is successfully completed. For more information on HTTP status codes, see matlab.net.http.StatusCode.

If the data received is null, the port outputs 0.

Example: An HTTP status code of 200 indicates that the read request is successfully completed. Whereas, an HTTP status code of 204, indicates that the data received on the data channel is null.

Data Types: single

Parameters

Channel ID — Channel ID from which block reads data

12397 (default) | any positive integer

Specify the channel ID from which the block reads data.

If you do not know the channel ID of your channel:

1. Sign In to ThingSpeak using your MathWorks^® Account.

2. Select Channels > My Channels.

3. Select the channel from which to read data.

4. Click the Channel Settings tab.

5. Copy the channel ID from the Channel ID parameter.

   

6. Open the ThingSpeak Read block in your model and paste the copied ID to the Channel ID parameter.

Channel access — Sharing settings of channel

Public (default) | Private

Specify if your channel is private or public.

If you do not know the sharing settings of your channel:

1. Sign In to ThingSpeak using your MathWorks Account.

2. Select Channels > My Channels.

3. Select the channel to get the sharing status.

4. Click the Sharing tab. Use the option selected in the tab to set Channel Access.

   • Keep channel view private: Set Channel Access to Private. Only you can view the channel data.

   • Share channel view with everyone: Set Channel Access to Public. Anyone browsing the ThingSpeak website can view the channel data.

   • Share channel view only with the following users: Set Channel Access to Private. Users who have access to shared channels can see only the private view of a channel; they cannot add channels, see alerts, or see license information.

   

Read API key — Key to read data from a private or shared channel

ABCDEFGHIJK (default) | any valid Read API Key

When you read data from your channel using the ThingSpeak API or MATLAB^® code, you need an appropriate read permission. The 16-digit API key allows you to read data from a private or a shared channel. You do not need an API key to read from a public ThingSpeak channel.

If you do not know the read API key of your channel:

1. Sign In to ThingSpeak using your The MathWorks^® Account.

2. Select Channels > My Channels.

3. Select the channel to get the read API key.

4. Click the API Keys tab.

5. Copy the key from the Read API Keys parameter.

   

6. Open the ThingSpeak Read block in your model and paste the copied API key into the Read API Key parameter.

Dependencies

• To enable this parameter, set Channel access to Private.

Fields to read — Field(s) of ThingSpeak channels to read data

1 (default) | [1 x N] vector, where N ranges from [1 to 8]

Enter the field(s) of the ThingSpeak channel from which the block reads the data. For example, if you set this parameter to [1 2 3], the block reads data from three fields and has three output ports field1, field2, and field3. If you set this parameter to 1, the block reads data from only one field and has one output port field1.

Print diagnostic messages — Save ThingSpeak server response to log file

off (default) | on

Select this parameter to save the response from the ThingSpeak server to a log file for each read request. The name of the log file has the format <model_name>.log.

Sample time — Interval at which block reads data from ThingSpeak channel

60 (default) | -1 | any nonnegative value

Specify how often this block reads data from the ThingSpeak channel.

When you set this parameter to -1, Simulink^® determines the best sample time for the block based on the block context within the model.

Version History

Introduced in R2016b