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I'd appreciate comment on whether I understand the limitations with MQTT and low power. Using deep sleep the ESP12 consumes microamps and my sensor is insignificant. The big drain on the battery is WiFi. Sending an MQTT message is taking around 10ms which seems at first sight promising. Unfortunately it looks to me like deep sleep ends the connection, and reconnection takes 4 or more seconds. I'd thought that deep sleep, static IP, and MQTT were the way to get very low power consumption but it looks to me like they don't solve the problem.

Unrecognized function or variable 'snopt'.

Error in Untitledidk (line 362) [x, f, inform, xmul, fmul] = snopt(xg, xlwr, xupr, xmul, xstate, ...

Hi , I am using M66 GSM Module to send and recv data over Thingspeak , TCP Connection : "api.thingspeak.com"; : Working Fine "GET /update?api_key=xxxxxxxxxxxxxxxx&field1=14"; : Send data to Server No Issue "GET https://api.thingspeak.com/update?api_key=xxxxxxxxxxxxxxxx&field1=12"; : Send sata to server No Issue .

But not able to see data in thingspeak view , it means thingspeak server not collecting data from M66 Module .

Could you please help the same .

Nowadays, many instructors are integrating AI to their courses. In a distance learning setting, the hardware students use to train their models vary. Training time of the deep learning models can be shortened with a pool of GPUs, CPUs or a pool of CPUs and GPUs locally or in the cloud. Accuracy of the results can depend on the hyperparameters used to train the models.

In MATLAB, Experiment Manager (introduced in R2020a) makes it easy to train networks with various hyperparameters and compare the results. Different models can be run in parallel by clicking on “Use Parallel” button in Experiment Manager App. But what if your computer has multiple CPU cores and a GPU? Would you be able to use Experiment Manager with a pool of CPUs and a GPU? The answer is “yes”. For example, my computer has 1 NVIDIA GPU and an 8 core CPU. To use all these computational resources, I typed these lines in my command window in MATLAB:

parpool(9);
spmd
if labindex==1
gpuDevice(1); %select GPU on worker 1
else
gpuDevice([]); %deselect GPU on remaining workers
end

Then, I clicked on “Use Parallel” button in Experiment Manager and used a modified setup function in Experiment Manager to change the execution environment from CPU to GPU:

if isempty(parallel.gpu.GPUDeviceManager.instance.SelectedDevice)
options=trainingOptions(~,"ExecutionEnvironment",'cpu');
else
options=trainingOptions(~,"ExecutionEnvironment",'gpu');
end 

Default training options automatically use an NVIDIA GPU if there is one, and specific hardware can be selected using “ExecutionEnvironment” in the trainingOptions.

If you like to learn more about the fundamentals of parallel computing, check out “Parallel Computing Fundamentals” on our documentation and gain some hands-on experience with Parallel Computing through "Parallel Computing Hands-On Workshop" .

Please can I run my MATLAB code on the cloud? The code involves calling the fuzzy logic toolbox for irrigation control and also collecting sensor data from farm.

Using the gauge widget works good, and the current value shows up below the gauge. But I've seen articles where the value is shown inside the gauge, not below it. It that possible to do? If so, how?

I do really like the ability of applying colors to ranges of the gauge's values. I'm plotting Air Quality AQI numbers and this works really well for that.

Thanks,

Rick

I am a new user to ThingSpeak. Generally things are going well. I've been able to create channels and use widgets. I am embedding charts into my own web site (using Google Sites) and that is working fine.

My question has to do with labels that I put on the charts in the 'public view'. I can change the title and the X and Y axis text and this shows up as I want. But when I click on the 'export URL' button and a new tab opens up with the chart, the title and X & Y labels are not what I put in (and yes, I did 'save' after changing them). Is this a bug, or is there some other thing I need to do here?

Thanks,

Rick

Im posting data every 10 minutes to this field as you can see, yet when i pull the data back down there are 2 timestamps in between each post with 'nothing' in them which in tern screws up any matlab script trying to average the data. Why is this happening? thanks see below

created_at,entry_id,field2
2021-08-21 09:54:27 -0600,38811,5.416666666666667
2021-08-21 09:57:02 -0600,38812,
2021-08-21 10:03:59 -0600,38813,
2021-08-21 10:04:27 -0600,38814,5.0
2021-08-21 10:07:02 -0600,38815,
2021-08-21 10:13:59 -0600,38816,
2021-08-21 10:14:28 -0600,38817,5.0
2021-08-21 10:17:03 -0600,38818,
2021-08-21 10:23:59 -0600,38819,
2021-08-21 10:24:28 -0600,38820,5.416666666666667
2021-08-21 10:27:03 -0600,38821,
2021-08-21 10:34:00 -0600,38822,
2021-08-21 10:34:29 -0600,38823,8.333333333333334
2021-08-21 10:37:04 -0600,38824,
2021-08-21 10:44:00 -0600,38825,
2021-08-21 10:44:29 -0600,38826,6.25
2021-08-21 10:47:09 -0600,38827,
2021-08-21 10:54:01 -0600,38828,
2021-08-21 10:54:30 -0600,38829,6.666666666666667
2021-08-21 10:57:10 -0600,38830,
2021-08-21 11:04:01 -0600,38831,
2021-08-21 11:04:34 -0600,38832,7.083333333333334
2021-08-21 11:07:10 -0600,38833,
2021-08-21 11:14:01 -0600,38834,
2021-08-21 11:14:35 -0600,38835,9.583333333333334
2021-08-21 11:17:11 -0600,38836,
2021-08-21 11:24:02 -0600,38837,
2021-08-21 11:24:35 -0600,38838,7.083333333333334

Educators use MATLAB Grader to automatically grade MATLAB code, to provide feedback to their students and to scale assessments for large lectures. If you use MATLAB Grader in our browser-based environment at grader.mathworks.com you can view various individual and aggregate student performance analytics. You can export the MATLAB Grader Assignment Report to analyze your student’s performance in more detail:

To make things easy for you, we provide a utility to create customizable assignment reports from the MATLAB Grader Assignment Report. With this utility you can quickly make lists of students with a metric that defines how well they solved the problems within the assignment. You can explore the number of problems each student solved correctly, calculate the mean percentage score they received for the problems or specify points per problem and calculate the points they scored on the assignment.

Please download the utility Customizable Assignment Report for MATLAB Grader from File Exchange. If you are new to MATLAB Grader, watch the MATLAB Grader Overview video and try the interactive Teaching with MATLAB online course (Section 6 is about MATLAB Grader).

The ThingSpeak Communication Library for Arduino, ESP8266 and ESP32 enables an Arduino or other compatible hardware to write or read data to or from ThingSpeak, an open data platform for the Internet of Things with MATLAB analytics and visualization.

Link: https://github.com/mathworks/thingspeak-arduino

Installation: In the Arduino IDE, choose Sketch/Include Library/Manage Libraries. Click the ThingSpeak Library from the list, and click the Install button.

Compatible Hardware:

• Arduino/Genuino or compatible using a WiFi Shield
• Arduino/Genuino or compatible using a WiFi Shield 101 (Use the WiFi101 library version 0.13.0 or older.)
• Arduino/Genuino or compatible using an Ethernet Shield
• Arduino/Genuino or compatible using a MKR ETH Shield
• Arduino MKR1000
• Arduino MKR1010
• Arduino VIDOR 4000
• Arduino GSM 14000
• Arduino Uno WiFi Rev2
• Arduino Yún (Rev1 and Rev2)
• ESP8266 programming directly (tested with SparkFun ESP8266 Thing - Dev Board and NodeMCU 1.0 module)
• ESP8266 via AT commands
• ESP32 (tested with SparkFun ESP32 Thing)

Tutorial: https://nothans.com/thingspeak-tutorials/arduino/send-data-to-thingspeak-with-arduino

Hi I got MatLab license for thingspeak. But I am not sure this MatLab is also valid for thingspeak or not? Do i need to buy add-on license for thingspeak?

An earlier tip suggested using MATLAB Drive to share and collaborate with others using MATLAB Online or MATLAB on desktop systems. Starting in MATLAB R2021a, there is yet another advantage of using this approach – the 'matlabdrive' function returns the path to the folder that contains the content of your MATLAB Drive.

After sharing their files, instructors sometimes direct students to navigate to a specified folder or add certain folders to the MATLAB search path. This ensures that MATLAB can discover the scripts, functions, and other files contained within. Since the MATLAB Drive folder may be installed in different locations on each users’ computer, this could not be done programmatically. Unfortunately, students may miss these instructions and encounter errors. The same can happen between peers working in groups.

Add the matlabdrive function in your code to obtain the path of the MATLAB Drive folder. You can then use functions cd and fullfile to navigate directly to that location or a subfolder. With addpath, you can also add these to the MATLAB search path. For example,

>> drivePath = matlabdrive 
drivePath = 'C:\Users\username\MATLAB Drive' 

>> folderPath = fullfile(matlabdrive, ‘myfolder’) 
folderPath = 'C:\Users\username\MATLAB Drive\myfolder’ 

>> cd(folderPath)	% Change current folder to ‘myfolder’ in MATLAB Drive 

You can run matlabdrive from your desktop or from other MATLAB environments such as MATLAB Online. On desktop systems, you must have MATLAB Drive Connector installed. If MATLAB is unable to find the MATLAB Drive folder, matlabdrive returns an error.

Hello, I was asked to help on a local community project to study Air Quality. I have two monitoring stations via PurpleAir. I can see data/ weekly graphs from both these stations. It appears that PurpleAir only holds/displays data for 1 week and it was suggested that ThingSpeak would [a]store historical data [b]able to "graph for longer periods of time". Is this true? Second question. It was only last week that I have heard of PurpleAir and ThingSpeak... is it possible for a Newbie to setup ThingSpeak to be able to visualize the AQI from my two monitors?

Hello, i use thingspeak to visualize data, when i use the chart, it works well, when i use numeric display, it show NaN.

How can i fix it?

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.