結果:

The mouse pointer can't convert into cross cursor when I attempted to open an image processing window so that I can't draw a line on the image.

I recently found some interesting hardware in a demo on Hackster. The Magicbit is an ESP32-based project platform. It includes some plug and play sensors and a built-in display on a brightly colored PCB. The demo shows how to send the data collected by the Magicbit to ThingSpeak. You can see how to use the Arduino IDE to program the device, using the ThingSpeak library for Arduino, ESP 8266, and ESP32 . Of course, once you get the data into ThingSpeak, you can use the integrated MATLAB to do just about anything with the data. The Magicbit is funded from a Kickstarter campaign .

The Symbolic Math Toolbox includes functions for solving, visualizing, and manipulating symbolic math equations. In combination with MATLAB’s Live Editor, it provides an easy, intuitive, and complete environment to interactively learn and teach algebra, calculus, and ordinary differential equations.

Starting with MATLAB R2021a, you can represent matrices and vectors in compact matrix notation with a new symbolic matrix variable data type. This enables a concise typeset display and show mathematical formulas with more clarity. Using them, you can show matrix- and vector-based expressions the way they are displayed in textbooks.

Contrast the visual difference between matrices of symbolic scalar variables and the new symbolic matrix variables:

The syms and symmatrix functions create symbolic matrix variables. To convert a symbolic matrix variable to an array of symbolic scalar variables, use symmatrix2sym. For an example, see Create Symbolic Matrix Variables.

Hi all,

I have created 2 fields in thingspeak, one which displays all datapoints and one which shows the daily average. In the thingview app, both graphs show all datapoints, not the average.

My simulink program require a feedback loop from an AC signal. How does one create a mean/ median value from a sinusoidal signal. Specifically, I want to average a power signal for last 0.1 sec and then adjust PWM signal.

Hello,

Opening TalkBack in Firefox and trying to Add a new command, the green button doing nothing. If I refresh the page, it works fine. First time have a issue - not work... Edge is working from the first time.

Buenas tardes. A ver tengo un problema que no se cómo solucionar. Tengo una estación méteo (Arduino) conectada a ThingSpeak y lo cierto es que funciona perfectamente, pero en los gráficos, tanto en el canal privado cómo en el público, me aparecen varias lecturas en una sola hora:

Como se puede observar, es muy mala cosa que en una sola hora aparezcan cuatro datos, algunas veces muy diferentes, ya que en una hora los valores reales pueden cambiar, con lo cual, no puedo hacerme una idea delas variaciones en 60 minutos. Esto ocurre con los datos de temperatura, humedad, presión y resto de gráficos.

Lo que quisiera conseguir, és que solo apareciera un solo dato por cada hora, durante las 24h del día. Es posible que únicamente imprima un punto y un dato a una sola hora en el gráfico? Cómo lo hago? Donde trasteo? Y con qué parámetros?

Agradeceré cualquier ayuda que me permita solucionar este tema.

Gracias por la atención y la ayuda.

Salu2 cordiales.

Thingsspeak : How to add multiple graphs in single field Ex: Real time monitoring 30 machines temperature in single graph (filed1)

Hi, i wonder if any one experiencing the same, but in my thing sepak profiel i can only see : 1- User API Key 2- Alert API Key

but no MQTT API key? not sure why Thank you

Hi,

I get 200 after a Python post to a channel like this from my Python script:

Ambient light: 13.3 lux Mass is 943.6 g 10:37 that is today, 7/24/2021 Pacific time <Response [200]

Yet the data is not showing up in the widget after 03:07 today and when I export the data it agrees with that:

2021-07-24 02:57:17 MDT 4123 947.4597598 0.833333333

2021-07-24 03:07:18 MDT 4124 947.5867868 0.833333333

here is a code snippet: note it posts every 10 minutes

-----------

request_headers = {'Content-Type':'application/json'}
          try:
             response = requests.post('http://api.thingspeak.com/update?api_key=' + API_KEY,
             json=planta_json, headers=request_headers)
             print(response)
          except:
             print("did not post for some reason")

------------

i never get a "did not post for some reason" debug message from the Python script. its like the data just disappears for some reason.

is there something else in the response i should look at to see why this happens? it will work fine for days then do this.

thanks

If your university is among the thousands worldwide with a Campus-Wide License, you have unlimited access to all MathWorks products. Therefore, when sharing your MATLAB code online or with collaborators and students, you may want to verify which add-ons or toolboxes it requires. You may also have received files and want to determine missing add-ons or toolboxes you need to install in order to run it.

Starting in R2021a, MATLAB’s Dependency Analyzer detects and lists required add-ons, including apps and toolboxes, for a whole MATLAB Project or for selected files. It can also identify which file is introducing a product dependency. For more details, see Find Required Products and Add-Ons.

I have Thingspeak MATLAB visualizations that I call using https://thingspeak.com/apps/matlab_visualizations/nnnnn?width=800&height=700 (where nnnnn is the visualization number). In the MATLAB code, is it possible to determine the width and height parameters that were sent, in this case 800 and 700?

Thanks! Tom

Hello Thingspeak supporter,

I see that the pleaform had updated the MQTT device feature. But I get the issue related to subscribe channel, please check my descripton below:

A Thingspeak device is added with permission of publish and subscribe to a channel. But when starting subscribe, the server disconnected MQTT connection to the device. I'm using MQTTbox tool for testing.

• MQTT setting ID, username and password (As thingspeak device info)

• Connect and publish OK

• MQTT is disconnected when starting subscibe

This issue doesn't appear when I use my old thingpseak account (before adding MQTT device feadure).

Please help me to check. Thank you!

Improving accessibility in higher education – whether on-campus or virtual – is important to ensure the learning experience accommodates all. MathWorks is committed to improving the accessibility of its software products for users with disabilities.

In MATLAB Online, you can use a screen reader to interact with the Command Window, create and edit scripts and functions in the Editor, and navigate through the MATLAB desktop tools. For more information, refer to the documentation page Use a Screen Reader in MATLAB Online .

You can learn more and sign up for usability research to improve the accessibility of MATLAB Online in the Accessibility Statement for MATLAB page.

Let me share with you how at TH Rosenheim we continued to conduct project-based engineering education with our students that could be conducted at home and outside.

How can students study and learn the development process on a real example? Three Master students from TH Rosenheim elaborated those steps on the design, simulation, manufacturing and the launch of a water rocket. The propulsion force comes from air, that is pumped into cola bottle with water inside. The bottle serves as pressure chamber; a fast opening of the bottle expels the water and pushes the rocket up. The right mixture of air and water has an influence on the reachable height. This was analysed and optimized. The pressure chamber has been with modern CAD tools and modelled by Finite-Element Methods and designed to sustain a pressure of up to 20 bar.

Attached to the rocket are the fins for aerodynamic stabilisation. A service module was set on top. It contains the survival mechanism of the rocket – a parachute, which needs to be expelled at the right moment in time. The proper command comes from the Raspberry Pi inside the module, the brain of the rocket. It collects and stores the sensor data and commands timer controlled the cap of the rocket to be opened to start a safe landing. The flight of the rocket has been simulated with the original CAD designed parts including launch site and animated using the Virtual Reality Toolbox. You find the 5-minutes-movie of the project here.

Do you have tips or questions? Do you know of similar projects? Then contact me!

Best regards,

Peter Zentgraf

For example, I can send my latest Thingspeak data to firebase platform? Or I can update my Thingspeak field data from Firebase?

Hello. First of all sorry for my English. I was checking that my daily message usage is about 1400/1500 and suddenly yesterday climbed to 13000. Any thoughts? Thanks in advance. Martín.-

generateFunction() failed in MathLab analysis and MathLab vis. where can i put generated function in the Apps->MathLab analysis list?

matlabdrive can show ans =

    '/MATLAB Drive'
in MathLab online and ThinkSpeak MathLab Analysis .
but show 
Unable to create file.

No one have saved once in MathLab online or ThinkSpeak MathLab Analysis ?

Hello to each other, I'm new here and wanted to test how it works with the transfer of data. To do this, I registered with ThingSpeak. I entered the API code in a Python script (see screenshot). Unfortunately, I always get the message: Response 400. When I enter the web address directly in the browser, I get a "0" back. I can't see an error entering the API key. Can you help me? I use a Raspberry 4B with the PIR sensor HC-SR501. The program will later run on a Raspberry Zero. Have a nice weekend everyone.