1.Introduction to ThingSpeak platform

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1 IoT laboratory 2. In the IoT laboratory 1. a sensors and an actuator were connected to the Internet in order to push data to an application and take control for the device. This time, at the laboratory the previous initial IoT platform will be enhanced with data analytics and visualization. The laboratory work is performed on the ThingSpeak platform. This platform has the right tools for data storage, analytics and visualization and it also features an API for sensor and application connections. The platform can be accessed via The measurements in the laboratory work are organized around different elements of the platform. The task of the student is to perform the measurements and report their results. The report should include the commands (program code) of the measurements, the configurations files and screenshots from the results. Basically the report should include everything to make the measurements and their results easily reproducible and understandable. The reports should be submitted (the preference is an online sharing) to the supervisor in an electronic form. This measurement work requires certain programming skills (e.g. MATLAB knowledge), however program code skeletons are provided, to make the task doable even without deep programming knowledge. 1.Introduction to ThingSpeak platform The ThingSpeak platform can be accessed via the web address. Students have to sign up for the service before they could use it. The registration is free. There are some limitation on the free account, however the laboratory work does not require more than that the free plan can offer. ThingSpeak organizes the incoming and outgoing data into so called channels. (In the IoT 1. measurement we also had MQTT channels.) Channels can be further divided into fields, where a field carries data for a single sensor. These fields provide the data for analytics, visualization and interactions. The sensor data in the channels can be shared among multiple users. Channels can be private or public. Furthermore, private channels can be shared as well, as there are separate read and write keys for a channel. In order to access a channel, the user have to know the id (a simple number) and the right key for the channel. In contrast to private channels, public channels do not require keys. Public channels are searchable. There are tags that help in the channel search. Measurement task Sign up to the ThingSpeak platform.

2 2. Create a private channel with multiple fields. Publish data to the channel using the MQTT method. The MQTT API has its documentation under the following link: You can use the MQTTfx application to create the connection to the ThingSpeak broker. 3. Search for a channel, where frequent and fresh weather data can be accessed. This weather channel should contain at least a field for temperature values, either in Celsius or Fahrenheit scale. In order to search channels, the Channels/Public Channels menu item can be used. The search is based on tags or username. Figure out the appropriate channel tag. Prefer Budapest or your own city/country. 2.Analytics In the ThingSpeak platform, such as with many other IoT platforms, we can perform analytics on the collected data. The analytics tool is provided by MathWorks using the MatLab language. The results of the analytics can be displayed on screen or they can be fed into another channel. In order to use the MathWorks tool for data analytics, you should be familiar with the MATLAB language first. This is a script language. A short course, based on your previous coding skills are available on the following pages: You will learn the syntax and the simple commands. Although the ThingSpeak platform has a MATLAB script run environment, where you can easily develop your code and watch for the results, experience shows that this is usually too slow for a dynamic development, plus the possible errors are not detailed well enough. In order to test your code, we would recommend an other page, which is On this page the development phase, with software bug squashing could be faster. This page is based on the Octave software, which is very close to the MATLAB code, however some special functions might be different here. Finally, of course the code should be copied into the ThingSpeak platform. You can reach ThingSpeak analytics starting from two different places. First, there is an Apps menu point. After this menu point, there is a MATLAB Analysis action. Second, the same MATLAB Analysis action appears on every channel page.

3 Either way, you will be transferred to the page where you can develop your MATLAB code. Based on your starting point, you can select to create a new code or edit an existing one. In the case of new codes, ThingSpeak provides code templates and examples, which can be used in the measurement as well.

4 A simple example is to change the temperature metric unit from Fahrenheit to Celsius. There is an example code for this in the new code menu:

5 Once this example code is created, a small MATLAB code will be inserted into the program code field. The code uses the public channel s 4th field. This is a MathWorks Weather Station at West Garage, Natick, MA 01760, USA. They provide wind, rain, temperature, humidity, pressure and light data in every minute. The code read the temperature value using the thingspeakread function (row 23). Check the documentation of this function! As the channel is public, there is no need for API key here. Later, the code transforms this Fahrenheit value into Celsius and displays it (rows 26 and 27). At the end there is an inactive code part, where the value could be written back to another channel. The thingspeakread function can be parameterized to give back values in a given time interval. The following example might help you solving the tasks: thingspeakread(readchannelid,'fields',temperaturefieldid,... 'DateRange',[datetime(datetime('now')-days(n)),... datetime(datetime('now')-days(n-1))]); Once the user press the Save and Run button, the code will be compiled and run. Finally the results are written into the output field. However, there is a possibility to run the code automatically, without any user interaction. Most often this is the requirement. In order to schedule the code for automatic run, the TimeControl action should be used. This action can be found at the bottom area of the page. Using this action, the parameters of the scheduling could be selected.

6 The most frequent scheduling is 5 minutes. The MATLAB environment provide functions to import data from various places, not just channels. For example, data can be scrapped from web pages. For this purpose we have the urlfilter function. It searches a string in the plain text fromat webpage and returns any numbers after this point. The number of the returned numbers can be set by a parameter. Check the documentation, how to use it! There is also an example code for this function. Measurement task Change the previously found weather channel s temperature data from Fahrenheit to Celsius (or vice versa). 2. Create a new channel and the necessary scheduled code which follows the previous channel s temperature data, converted from Fahrenheit to Celsius (or vica versa) automatically. 3. Collect data from a web page and put it on a channel. Use a Hungarian or your own nation s weather info page, read the data and feed it into a channel. You can use the ThingSpeak example code, however there you will find a US data source, which is limited to serve US IP addresses only. Find another one, which provides data at least in every 10 minutes. Find a data source with multiple weather data, just like wind, temperature, humidity, etc.. As the scheduling is not so frequent and the data source could be infrequent as well, continue with other tasks and come back here later, or at the end of the measurement to take nice screenshots for the documentation.

7 3.Visualization The ThingSpeak platform supports two kinds of visualization elements. You can choose the MATLAB visualization, which are basically figures, or there is a possibility to use arbitrary HTML based widget. A measurement task is to test both methods for visualization. MATLAB provides functions to create a figure based on a dataset. The most simple figure drawing functions are: plot, scatter, hist, stem and bar. Many examples can be found on the following page:

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9 A 6 minute video tutorial on plotting functions can be found at the following page: In order to access the visualization functions, the starting points are similar to the programming points. First, there is a MATLAB Visualizations menu point in the Apps menu header, second, there is a button on the channel s page. Really similar to the analytics, there are templates and examples here as well. There is a simple example code to display a histogram over the last 24 hours temperature variation. The screen will be similar to the analytics page. As a difference, here the graphics can be attached to a channel, using the display settings actions at the bottom of the page. The example code use the same channel as it was at the analytics and draw a histogram. In order to read data from the channel, we use the same thingspeakread function (row 22), but now we give the interval using time parameters. The values we read are placed into a vector. The figure is created using the histogram function (row 25). Later the figure is formatted using labels and a title.

10 In order to place the visualized data into a channel, we can use the Add/Edit this Visualization to a Channel action. A drop down channel list will appear and one can select the desired channel for the display. In addition to the MATLAB figures, there is a possibility to use arbitrary HTML, CSS and JavaScript visualization component. To select this option, one should select the Add visualization placeholder on the bottom of the channel s page. Or else, it is possible to start with the Plugins menu point, behind the Apps menu. Writing a new visualization may contain three parts: an HTML code + a CSS code, which are for the graphics and a JavaScript code, which is for data processing. This API is documented in the following page: It is relatively easy to select a Google chart. A gallery of the available charts is on this address:

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12 Most of the charts are interactive. Measurement task Based on the ThingSpeak example, display a temperature histogram on the data of the previously selected weather channel 2. Create graphs that display the weather channel data in a hourly average format for the last 24 hours 3. Create a code, which compares on a graph the last 7 days and the preceding 7 days daily average temperature. In MATLAB you should use the hold on command in order to keep the previous graph on the figure. 4. Create an nice HTML/Javascript widget displaying the current temperature and humidity on a weather channel. Use google widgets and modify the html + javascript code. 4.Act, based on the data The ThingSpeak platform provides reaction triggers when certain conditions happen during the analytics. Possible reactions include Twitter messaging and sending an almost arbitrary constructed HTTP message, called ThingHTTP. The measurement task uses the latter one. Here the task is to analyze a channel data and in a certain condition, send a message to a mobile phone (or browser). Here are the actions that are currently supported by the platform:

13 In order to reach the mobile phone (or your browser) we will use the PushBullet platform. The PushBullet service connects mobile phones and browser applications simply in order to receive messages. The sent messages are reaching the user on all platforms. The service is free, but a google or a facebook account is required for the registration. The service can be accessed on the page: When you install the PushBullet app or extension to your mobile phone or your browser, after signing in the device will be registered. Our approach is the following: We use the ThingSpeak platform to analyze the data on a given channel. We set an action based on the result of the analysis. This action, still on the ThingSpeak platform, will construct a message and call a web service to deliver it. This web service is provided by PushBullet that receives the data and send it to the receiver we already set. The description of the PushBullet API is accessible from the top menu row. Here you can find, how to send a message to your own registered devices. The message is called push here. Find the create-push description on the left side, there you can find how to call this web service. There is an example command for the curl utility: curl --header 'Access-Token: <your_access_token_here>' \ --header 'Content-Type: application/json' \ --data-binary '{"body":"space Elevator, Mars Hyperloop, Space Model S (Model Space?)","title":"Space Travel Ideas","type":"note"}' \ --request POST \ (There is no need for curl in order to finish with the measurements. This is just an example.) The displayed message is a JSON format string. It should have a body, a title and a type part. In our case the type is note. The address of the web service is and it is a POST request. When you use the service, the content type should be set to application/json, and there should be an extra header with the access token. The access token can be generated on the My Account page.

14 On the ThingSpeak side the ThingHTTP can be create starting from the Apps menu point. On the corresponding page the details of the webservice should be entered.

15 After the ThingHTTP setup, on the top right corner there will be a web address. Calling this address can test the ThingHTTP action. Using the right parameters, there should be no error message, but a confirmation of the sent message. ThingHTTP is able to fill the body part with values taken from channels. In order to pick the last value from a channel s field the following string should be inserted into the body: %%channel_ XXX _field_ YYY %% Where the XXX should be substituted with the channel ID, and the YYY with the field number. ThingSpeak will replace this pattern with the actual value.

16 Uring the React menu pont in the Apps menu, reactions can be set. The reaction can be based on a condition, which reads a channel s field and perform some operations. The condition is tested either regularly or on a new value arrival. The action can be a ThingHTTP. Measurement task Register on the PushBullet service 2. Connect your own smartphone and/or browser. Install the necessary apps or browser plugins 3. On the ThingSpeak platform, create a ThingHTTP command, which analyzes the National/Hungarian weather channel info and periodically sends the temperature data to the smartphone using the PushBullet service 4. Create a trigger event when a new temperature value is appearing on the National/Hungarian weather channel. Send the weather conditions in the message 5.The end of the measurements Check whether the Hungarian/national weather channel works as it should be. As data is coming usually on a 5-10 minutes interval, the channel should already contain a fair amount of data. Make all created channels public! Create tags on the channel with iot2 and meres labels. Put the number of the channels into the report. Keep the channels till the end of the semester, as they could be checked later. Ask the supervisor how to submit the report.

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