thingSpeakRead
Read data stored in ThingSpeak channel
Syntax
Description
reads the most recent data from all fields of the specified public channel on ThingSpeak.com and returns the data as a
numeric type.data
= thingSpeakRead(channelID
)
uses additional options specified by one or more data
= thingSpeakRead(channelID
,Name=Value
)Name=Value
pair
arguments. To read nonnumeric data, you must specify the
'OutputFormat'
.
[
also returns timestamps from the specified channel on ThingSpeak.com and can include any of the
input arguments in previous syntaxes.data
,timestamps
]
= thingSpeakRead(___)
[
also returns channel information.data
,timestamps
,channelInfo
]
= thingSpeakRead(___)
Examples
Retrieve Three Points of Data from a Channel into a Timetable
Read the last three points of data from fields 1 and 4 of a public channel, and return the data into a timetable.
data = thingSpeakRead(12397,'Fields',[1,4],NumPoints=3,OutputFormat='TimeTable')
data = 3×2 timetable Timestamps WindDirectionNorth0Degrees TemperatureF ____________________ __________________________ ____________ 18-Nov-2021 13:42:57 34 70.4 18-Nov-2021 13:43:57 50 70.4 18-Nov-2021 13:44:57 54 70.6
Retrieve Five Minutes of Data from a Channel into a Timetable
Read the last five minutes of data from fields 1 and 4 of a public channel, and return the data into a table.
data = thingSpeakRead(12397,Fields=[1,4],NumMinutes=5,OutputFormat='TimeTable')
data = 11×2 timetable Timestamps WindDirectionNorth0Degrees TemperatureF ____________________ __________________________ ____________ 18-Nov-2021 13:34:57 38 70.6 18-Nov-2021 13:35:57 42 70.6 18-Nov-2021 13:36:57 41 70.6 18-Nov-2021 13:37:57 46 70.8 18-Nov-2021 13:38:57 44 70.8 18-Nov-2021 13:39:57 37 70.8 18-Nov-2021 13:40:57 42 70.6 18-Nov-2021 13:41:57 43 70.4 18-Nov-2021 13:42:57 34 70.4 18-Nov-2021 13:43:57 50 70.4 18-Nov-2021 13:44:57 54 70.6 18-Nov-2021 13:45:57 52 70.
Retrieve Recent Data with Its Timestamp
Read the most recent result for all fields of a public channel, including the timestamp.
[data,timestamps] = thingSpeakRead(12397)
data = 52.0000 7.6000 58.0000 70.8000 0 29.6700 4.1360 0 timestamps = datetime 18-Nov-2021 13:45:57
Retrieve Five Minutes of Data with Timestamps and Channel Information
Read the last five minutes of data from fields 1 and 4 of a public channel, including the timestamps and channel information.
[data,timestamps,channelInfo] = thingSpeakRead(12397,Fields=[1,4],NumMinutes=5)
data = 41.0000 70.6000 46.0000 70.8000 44.0000 70.8000 37.0000 70.8000 42.0000 70.6000 43.0000 70.4000 34.0000 70.4000 50.0000 70.4000 54.0000 70.6000 52.0000 70.8000 39.0000 71.0000 timestamps = 11×1 datetime array 18-Nov-2021 13:36:57 18-Nov-2021 13:37:57 18-Nov-2021 13:38:57 18-Nov-2021 13:39:57 18-Nov-2021 13:40:57 18-Nov-2021 13:41:57 18-Nov-2021 13:42:57 18-Nov-2021 13:43:57 18-Nov-2021 13:44:57 18-Nov-2021 13:45:57 18-Nov-2021 13:46:57 channelInfo = struct with fields: ChannelID: 12397 Name: 'WeatherStation' Description: 'MathWorks Weather Station, West Garage, Natick, MA 01760, USA' Latitude: 42.2997 Longitude: -71.3505 Altitude: 60 Created: 20-May-2014 17:50:32 Updated: 18-Nov-2021 13:40:31 LastEntryID: 3638608 FieldDescriptions: {1×8 cell} FieldIDs: [1 2 3 4 5 6 7 8] URL: 'https://api.thingspeak.com/channels/12397/feed.json?'
Retrieve Data from a Specific Date Range
Read the data from 11:59:01 on August 9, 2018 through 12:02:52 on August 10, 2018 for fields 1 and 4 of a public channel, including the timestamps and channel information.
[data,timestamps,channelInfo] = thingSpeakRead(12397,Fields=[1 4],...
DateRange=[datetime(2018,8,9,23,59,01),datetime(2018,8,10,0,02,52)])
data = 202.0000 83.3000 184.0000 83.2000 185.0000 83.1000 155.0000 83.1000 timestamps = 4×1 datetime array 09-Aug-2018 23:59:17 10-Aug-2018 00:00:20 10-Aug-2018 00:01:21 10-Aug-2018 00:02:22 channelInfo = struct with fields: ChannelID: 12397 Name: 'WeatherStation' Description: 'MathWorks Weather Station, West Garage, Natick, MA 01760, USA' Latitude: 42.2997 Longitude: -71.3505 Altitude: 60 Created: 20-May-2014 17:50:32 Updated: 14-May-2020 10:31:40 LastEntryID: 2853000 FieldDescriptions: {'Wind Direction (North = 0 degrees)' 'Wind Speed (mph)' '% Humidity' 'Temperature (F)' 'Rain (Inches/minute)' 'Pressure ("Hg)' 'Power Level (V)' 'Light Intensity'} FieldIDs: [1 2 3 4 5 6 7 8] URL: 'https://api.thingspeak.com/channels/12397/feed.json?'
Input Arguments
channelID
— Channel identification number
numeric
The channel identification number, specified as a positive integer. For private
channels, you must also specify the ReadKey
argument.
Data Types: double
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: thingSpeakRead(12397,Location=true);
thingSpeakRead(12397,'Location',true);
DateRange
— Range of time for collected data
datetime vector
Range of time for collected data to return, specified as a name-value pair
consisting of 'DateRange'
and an array of values that have
[startdate,enddate]
in MATLAB®
datetime
(MATLAB) values. ThingSpeak server limits the number of points returned to a maximum of 8000. Adjust
your ranges or make multiple calls if you need more than 8000 points of data.
Note
You cannot use DateRange
with NumDays
or
NumMinutes
.
Example: thingSpeakRead(12397,DateRange=[datetime('Aug 8,
2014'),datetime('Aug 12, 2014')]);
Fields
— Channel fields
positive numeric scalar
Channel field IDs, specified as a name-value pair consisting of Fields
and
numeric values of the channel field ID to retrieve data from.
Example: thingSpeakRead(12397,Fields=[1,3,4]);
Location
— Positional information of data
logical
Indicator to display positional information of data from the channel, specified as a
name-value pair consisting of Location
and a logical value.
Location information includes latitude, longitude, and altitude.
Example: thingSpeakRead(12397,Location=true);
NumDays
— Number of days of data
positive numeric scalar
Number of days of data to extract data from, specified as a name-value pair consisting of
'NumDays'
and a numeric value. Number of days is measured in
24-hour periods. The ThingSpeak server limits the number of points returned to a maximum of 8000. Adjust
your number of days, or make multiple calls if you need more than 8000 points of
data.
Note
You cannot use NumDays
with DateRange
or NumMinutes
.
Example: thingSpeakRead(12397,NumDays=2);
NumMinutes
— Number of minutes of data
positive numeric scalar
Number of minutes of data to extract data from, specified as a name-value pair consisting of
'NumMinutes'
and a numeric value. Number of minutes of data to
retrieve is measured from the time the command is issued. The ThingSpeak server limits the number of points returned to a maximum of 8000. Adjust
your number of minutes, or make multiple calls if you need more than 8000 points of
data.
Note
You cannot use NumMinutes
with DateRange
or NumDays
.
Example: thingSpeakRead(12397,NumMinutes=20);
Data Types: double
NumPoints
— Number of data points
positive numeric scalar
Number of data points to extract, specified as a name-value pair consisting of
'NumPoints'
and a numeric value. The number of points or rows of
data is counted from the time the command is issued. The ThingSpeak server limits the number of points returned to a maximum of 8000.
Example: thingSpeakRead(12397,NumPoints=200);
OutputFormat
— Class of the output data
matrix (default) | table | timetable
Class of the output data, specified as a comma-separated pair
consisting of 'OutputFormat'
and a text value.
Valid values are 'matrix'
, 'table'
,
and 'timetable'
. Use 'matrix'
format
for numeric data. You can use 'timetable'
or 'table'
for
any nonnumeric data. The 'table'
format outputs [data,channelInfo]
,
where data
contains the timestamps and the data
from the fields of the channel. The 'timetable'
format
outputs [data,channelInfo]
, where data
is
a timetable and contains as many variables as the number of requested 'fields'
.
Example: thingSpeakRead(12397,OutputFormat='table');
Example: thingSpeakRead(12397,OutputFormat='timetable');
ReadKey
— Read API key of channel
character vector of API Key | string scalar of API Key
Read API key of the channel, specified as a name-value pair consisting of
'ReadKey'
and a character vector representing a channel read API
key. The Read API key allows you to read data from a private channel. You can find the
Read API key for a channel on the API Keys tab of your ThingSpeak channel view. If you
are reading data from a public channel, you do not need a Read API key. Save your
channel Read API key in a variable for convenience.
Example: thingSpeakRead(12397,ReadKey='F6CSCVKX42WFZN9Y');
Data Types: char
Timeout
— Server connection timeout period
10 (default) | positive numeric scalar
Server connection timeout period, specified as a name-value pair consisting of
'Timeout'
and a numeric value. The value is the number of seconds
allowed for thingSpeakRead
to connect to the server.
Example: thingSpeakRead(12397,Timeout=15);
Output Arguments
data
— Data from the channel
array (default) | table | timetable
Data from the channel, returned as an array, table, or timetable.
timestamps
— Timestamp of each data element
array (default)
Timestamp of each data element, returned as an array of datetime
values.
Data Types: datetime
channelInfo
— Channel information
structure
Channel information, returned as a structure with fields in the order shown in the table..
Field | Description |
---|---|
ChannelID | Channel identification number |
Name | Name of the channel |
Description | Channel description |
Latitude | Latitude for the channel as provided in the channel settings |
Longitude | Longitude for the channel as provided in the channel settings |
Altitude | Elevation for the channel as provided in the channel settings |
Created | Datetime of channel creation date |
Updated | Datetime when the channels settings were last changed |
Last EntryID | Entry ID for the most recent channel update |
Field Descriptions | List of field names |
Field IDs | List of enabled fields |
URL | URL for feed data |
More About
ThingSpeak
ThingSpeak is an IoT analytics platform service that allows you to aggregate, visualize, and analyze live data streams in the cloud. See License Options and the Commercial Use for more information.
Version History
Introduced in R2019a
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