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Hello! I use 3 sensors and send the data via esp8266 to thingspeak. I want to take the data from thingspeak and send it to an html page created by me but I haven't worked with thingspeak so far and I don't know how I should proceed. Is there anyone who can help me? An example code that takes data from thingspeak would help me a lot.

We introduced Difficulty Rating functionality during 2020 Cody Contest. Our Cody players have provided difficulty rating for most of the problems. Now we are displaying the ratings in the Problems list view.

Sorting and Filtering to follow...

Many educators use Simulink for their virtual labs. Starting in R2021a, you can add comments to blocks in a Simulink model. If you use Simulink in your class, you can use this to prompt questions to your students or to provide them feedback. Students working in groups can collaborate directly in the Simulink Editor, such as by suggesting alternative designs.

Click here to learn how to view, add, and reply to comments on blocks.

You may also want to learn more about Virtual Labs and Projects with MATLAB and Simulink, or read some Tips for Moving your Lab-based Classes Online.

I am a student with 2 others in my project. we connected 3 RPi sending temp and pressure to my Project channel using fields 1,2 3,4, and 5,6 we were publishing the data from 3 python scripts i wrote and everything was working great and the charts were update then it just stopped publishing. I thought it might be a license/message problem as i was sending information every 1 sec so I changed it to ever 60 sec. Everything worked fine again for 5 minutes and then it all crashed It will not let me reconnect and i can't see any data updating from the other Rpi's any Do you have a technical help line or how should i proceed.

I find this is possible to do, but how does one read the data back.

Buena tarde, he estado tratando de cambiar toda la configuración, con distintos correos para ver si me lanzaba el aviso de fuera de rango de temperatura, pero no he podido lograrlo. También baje una app Ilo thingspeak, para celular, pero tampoco me activa las alarmas. les agradecería su ayuda. gracias. Mensajes a correo,willfree66@outlook.com

Im not able to upload a csv file which I have created using rpi. The csv file is as follows

datetime field1 field2 field3 2021-04-19-10:59:46 0 0 0 2021-04-19-10:59:47 122 -1 265 2021-04-19-10:59:48 123 -1 265 2021-04-19-10:59:49 115 0 266 2021-04-19-10:59:50 122 -7 265 2021-04-19-10:59:51 117 -5 265 the error I get is invalid csv file or contains duplicate timestamp or missing timestamps. If someone could point out the mistake, it would be helpful.

I am having issues with my two channels

https://thingspeak.com/channels/513058

https://thingspeak.com/channels/971602

when I try to view them without being logged in. The channels are public (and have always been that way). I have those links on my desktop and also have them as favourites in my browser. Using any of these will ead to the following behavior

1. The public view of the channels starts to load
2. Widgeds etc start to be filled (see attached file Scrennhunter_309.png)
3. The display view closes after a few seconds and shows the Mathwork/Thingspeak sign on screen with a message box saying "Signed out successfully" (see attached file ScreenHunter_310.png)

In order to circumvent the issue, I have

• deleted the cache
• deleted all mathwork cookies
• deleted all thingspeak cookies

The issue prevails. I have then

• deleted the cache
• deleted all cookies

The issue prevails.

I tried

• Firefox browser Version 78.9.0esr (32-Bit)
• Internet explorer, newest Version
• Microsoft Edge, newest Version

The issue prevails

I tried 3 different PCs, each running Windows 10 pro 20H2 (build 19042.928) with all current updates installed

The issue prevails

I tried my Safari browser on my ipad Pro - no issue there!!, neither on my iPhone.

What am I missing? What can/shoud I do?

With best regards vom Germany

Volker Bandke

Everytime I try to log onto my thingspeak the webpage keeps refreshing. Have to stop loading page and every page I go to keeps refreshing.

Introducing content recommendations, a new feed on the community home page with personalized content just for you. MATLAB Central has hundreds of thousands of posts, including files, blogs, questions, and answers. We’re always looking for opportunities to better serve the community as it continues to grow so that visitors can easily help one another and ultimately find what they're looking for.

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Hi,

 Recently, I'm trying to view any Public channel (including my public channel). It opens the channel a second and redirects to the login page. Is there any way to see a public channel without login?

S.

I'm testing use of a 3g dongle which is pay as go (in the UK). I'm sending messages to Thingspeak (via Python on Pi) but the credit allowance decrease indicates several megabytes have been used. Even if one message is 1,000 bytes then after 1,000 messages like this I'd expect to lose 1 megabyte of credit but instead it's 10 MB (I'm sending https://api.thingspeak.com/update?api_key=xxxxxxxxxxxxx&field3=12345 ) Has anyone experience of data logging over a mobile data dongle and how much it should cost ?

New in R2021a, LimitsChangedFcn

LimitsChangedFcn is a callback function that responds to changes to axis limits ( release notes ). The function responds to axis interaction such as panning and zooming, programmatically setting the axis limits, or when axis limits are automatically adjusted by other processes.

LimitsChangedFcn is a property of ruler objects which are properties of axes and can be independently set for each axis. For example,

ax = gca(); 
ax.XAxis.LimitsChangedFcn = ... % Responds to changes to XLim
ax.YAxis.LimitsChangedFcn = ... % Responds to changes to YLim
ax.ZAxis.LimitsChangedFcn = ... % Responds to changes to ZLim

Previously, a listener could be assigned to respond to changes to axis limits. Here are some examples.

• Update refline when axis limits change
• Update axis2 limits when axis1 limits change

However, LimitsChangedFcn responds more reliably than a listener that responds to setting/getting axis limits. For example, after zooming or panning the axes in the demo below, the listener does not respond to the Restore View button in the axis toolbar but LimitsChangedFcn does! After restoring the view, try zooming out which does not result in changes to axis limits yet the listener will respond but the LimitsChangedFcn will not. Adding objects to axes after an axis-limit listener is set will not trigger the listener even if the added object expands the axis limits ( why not? ) but LimitsChangedFcn will!

ax = gca(); 
ax.UserData.Listener = addlistener(ax,'XLim','PostSet',@(~,~)disp('Listener')); 
ax.XAxis.LimitsChangedFcn = @(~,~)disp('LimitsChangedFcn')

How to use LimitsChangedFcn

The LimitsChangedFcn works like any other callback. For review,

• Callback Definition
• Write Callbacks for Apps

The first input to the LimitsChangedFcn callback function is the handle to the axis ruler object that was changed.

The second input is a structure that contains the old and new limits. For example,

    LimitsChanged with properties:

      OldLimits: [0 1]
      NewLimits: [0.25 0.75]
         Source: [1×1 NumericRuler]
      EventName: 'LimitsChanged'

Importantly, since LimitsChangedFcn is a property of the axis rulers rather than the axis object, changes to the axes may clear the LimitsChangedFcn property if the axes aren't held using hold on. For example,

% Axes not held
ax = gca(); 
ax.XAxis.LimitsChangedFcn = @(ruler,~)title(ancestor(ruler,'axes'),'LimitsChangedFcn fired!'); 
plot(ax, 1:5, rand(1,5), 'o')
ax.XAxis.LimitsChangedFcn

ans =
    0×0 empty char array

% Axes held
ax = gca(); 
hold(ax,'on')
ax.XAxis.LimitsChangedFcn = @(ruler,~)title(ancestor(ruler,'axes'),'LimitsChangedFcn fired!'); 
plot(ax, 1:5, rand(1,5), 'o')
ax.XAxis.LimitsChangedFcn

ans =
  function_handle with value:
    @(ruler,~)title(ancestor(ruler,'axes'),'LimitsChangedFcn fired!')

Demo

In this simple app a LimitsChangedFcn callback function is assigned to the x and y axes. The function does two things:

1. Text boxes showing the current axis limits are updated
2. The prying eyes that are centered on the axes will move to the new axis center

This demo also uses Name=Value syntax and emoji text objects !

Create app

h.fig = uifigure(Name="LimitsChangedFcn Demo", ...
    Resize="off");
h.fig.Position(3:4) = [500,260];
movegui(h.fig)
h.ax = uiaxes(h.fig,...
    Units="pixels", ...
    Position=[200 26 250 208], ...
    Box="on");
grid(h.ax,"on")
title(h.ax,"I'm following you!")
h.eyeballs = text(h.ax, .5, .5, ...
    char([55357 56385 55357 56385]), ...
    HorizontalAlignment="center", ...
    FontSize=40);
h.label = uilabel(h.fig, ...
    Text="Axis limits", ...
    Position=[25 212 160 15], ...
    FontWeight="bold",...
    HorizontalAlignment="center");
h.xtxt = uitextarea(h.fig, ...
    position=[25 191 160 20], ...
    HorizontalAlignment="center", ...
    WordWrap="off", ...
    Editable="off",...
    FontName=get(groot, 'FixedWidthFontName'));
h.ytxt = uitextarea(h.fig, ...
    position=[25 165 160 20], ...
    HorizontalAlignment="center", ...
    WordWrap="off", ...
    Editable="off", ...
    FontName=get(groot, 'FixedWidthFontName'));
h.label = uilabel(h.fig, ...
    Text=['X',newline,newline,'Y'], ...
    Position=[10 170 15 38], ...
    FontWeight="bold");

Set LimitsChangedFcn of x and y axes

h.ax.XAxis.LimitsChangedFcn = @(hObj,data)limitsChangedCallbackFcn(hObj,data,h,'x');
h.ax.YAxis.LimitsChangedFcn = @(hObj,data)limitsChangedCallbackFcn(hObj,data,h,'y');

Update text fields

xlim(h.ax, [-100,100])
ylim(h.ax, [-100,100])

Define LimitsChangedFcn

function limitsChangedCallbackFcn(rulerHand, limChgData, handles, xy)
% limitsChangedCallbackFcn() responds to changes to x or y axis limits.
% - rulerHand: Ruler handle for x or y axis that was changed (not used in this demo)
% - limChgData: LimitsChanged data structure
% - handles: structure of App handles
% - xy: either 'x' or 'y' identifying rulerHand
switch lower(xy)
    case 'x'
        textHandle = handles.xtxt;
        positionIndex = 1; 
    case 'y'
        textHandle = handles.ytxt;
        positionIndex = 2; 
    otherwise
        error('xy is a character ''x'' or ''y''.')
end
% Update text boxes showing rounded axis limits
textHandle.Value = sprintf('[%.3f, %.3f]',limChgData.NewLimits);
% Move the eyes to the new center position
handles.eyeballs.Position(positionIndex) = limChgData.NewLimits(1)+range(limChgData.NewLimits)/2; % for linear scales only!
drawnow
end

See attached mlx file for a copy of this thread.

Highlight Icon image

HI! The following line works well to send my var1 value to thingspeak.

GET https://api.thingspeak.com/update?api_key=****************&field1={var1}

But I would like to send the addition of var1+var2 in the same command. I tried many differents commands like:

    GET https://api.thingspeak.com/update?api_key=****************&field1={var1+var2}

any help? Thanks

We will be hosting a seminar on MATLAB Grader, the product I manage at MathWorks, on April 21st at 7am EDT. If you are interested in adding autograding capabilities for #MATLAB to your course, MOOC, textbook, or learning environment and have questions, please join this seminar and take part in the live Q&A with the product team the following week. #autograding #assessments #onlineassessment #onlineteaching

MathWorks Seminar: Autograded Assessments with MATLAB Grader & LMS Integration

Javascript based plugins no longer working properly (in private views). Its just not displayed in channels. (Shown as field Sections are empty)

I can no longer open and view my Thingspeak results in Firefox. It gets stuck in a loop which alternates between telling me I've logged in and authenticating. I've tried clearing Thingspeak cookies and rebooting the PC.

The same page works in Chrome, but I prefer to use Firefox as my browser. Any ideas what is wrong ?

Hello

From earlier today a project i've been working on has stopped working. It was working for the last couple of weeks with no coding updates in the mean time.

The error i'm only now getting is

"from origin 'null' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource."

Im transferring four readings from thingspeak to a web page

the get command i'm using is. xhttp.open("GET", "https://api.thingspeak.com/channels/752230/feeds/last", false); xhttp.send();

Why would i only start receiving this error today. If more information is needed i will send it on.

any insights would be much appreciated.

Thanks

Trev

Hello, since today 14:00 CEST (UTC+2) (= 12:00 UTC = 4 hours ago) none of my thinkspeak clients running on Arduinos using PubSubClient are able to connect to mqtt.thingspeak.com. Until then, they have been running happily for months.

I tried to send some data manually but didn't succeed:

mosquitto_pub -d -h mqtt.thingspeak.com -u TESTTerrasseWemos -p 1883 -P xxxx -t "channels/cccc/publish/yyyy" -m "field1=10&field2=60" ; echo $?
Client mosq-xxxxxxx sending CONNECT
Error: Unknown error.
19

The exact errors differ from try to try. But I don't know if my call is definitely correct.

Any help or information what might have changed at mqtt.thingspeak.com?

Thank you very much.