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Exciting news for students! 🚀Simulink Student Challenge 2023 is live! Unleash your engineering skills and compete for exciting rewards. Submission deadline is December 12th, 2023!
Over the weekend I came across a pi approximation using durations of years and weeks (image below, Wolfram, eq. 89), accurate to 6 digits using the average Gregorian year (365.2425 days).
Here it is in MATLAB. I divided by 1 week at the end rather than multiplying by its reciprocal because you can’t divide a numeric by a duration in MATLAB (1/week).
weeks = @(n)n*days(7);
piApprox = ((years(13)-weeks(6))/years(13) + weeks(3)) / weeks(1)
% piApprox = 3.141593493469302
Here’s a breakdown
  • The first argument becomes 12.885 yrs / 13 yrs or 0.99115
  • Add three weeks: 0.99115 + 3 weeks = 21.991 days
  • The reduced fraction becomes 21.991 days / 7 days
Now it looks a lot closer to the more familiar approximation for pi 22/7 but with greater precision!
This person used computer version to build a keyboard input, and used standard flag semaphore for the positions.
Flag semaphore is used mostly by sailors to be able to communicate optically over a distance; it does not need anything more than make-shift flags (but binoculars or telescopes can help.) Trained users can go faster than you might guess.
Chen, Rena, and I are at a community management event. It's great to be with others talking about relationships, trust, and co-creation.
A research team found a way to trick a number of AI systems by injecting carefully placed nonsense -- for example being able able to beat DeepMind's Go game.
This video discusses the "Cody" bridge, which is a pedestrian bridge over a canal that has been designed to move up and out of the way when ships need to travel through. The mathematics of the bridge movement are discussed and diagrammed. It is unique and educational.
Recently developed: a "microscope" based on touch and stereo vision.
Using touch removes the possibility of optical confusion -- for example, black on touch is only due to shape, not due to the possibility that the object has a black patch.
Sorry, you might need a Facebook account to watch the video.
Adam Danz
Adam Danz
Last activity on 6 Mar 2024

I'm curious how the community uses the hold command when creating charts and graphics in MATLAB. In short, hold on sets up the axes to add new objects to the axes while hold off sets up the axes to reset when new objects are added.
When you use hold on do you always follow up with hold off? What's your reasoning on this decision?
Can't wait to discuss this here! I'd love to hear from newbies and experts alike!
The way we've solved ODEs in MATLAB has been relatively unchanged at the user-level for decades. Indeed, I consider ode45 to be as iconic as backslash! There have been a few new solvers in recent years -- ode78 and ode89 for example -- and various things have gotten much faster but if you learned how to solve ODEs in MATLAB in 1997 then your knowledge is still applicable today.
In R2023b, there's a completely new framework for solving ODEs and I love it! You might argue that I'm contractually obliged to love it since I'm a MathWorker but I can assure you this is the real thing!
The new interface makes a lot of things a much easier to do. Its also setting us up for a future where we'll be able to do some very cool algorithmic stuff behind the scenes.
Let me know what you think of the new functionality and what you think MathWorks should be doing next in the area of ODEs.
Shore
Shore
Last activity on 11 Oct 2023

I wanted to write to my public channel 2278931 with 8 different values to 8 different gauge widgets.
Here is my link.
https://api.thingspeak.com/update.json?api_key=xxxxxxxxxxxxxxxx&field1=1&field2=2&field3=3&field4=4&field5=5&field6=6&field7=7&field8=8
You can change values and in the link to change gauge values. On edit I edited my write key to make it not work for others but it will work with your own key.

Up until a few weeks ago, there was a "channels shared with me" option in Thingspeak. I was able to access the channel created by a different user, only once. The next time me and my groupmate tried to open the channel, there wasn't a "channels shared with me" option anymore. Why is that and how can this be resolved?

Is there any problem from thingspeak side, from last month my data is not uploading
Currently, I am trying to setup MATLAB and Simulink to connect with Unity. But I have some questions about the installation of ROS on my computer and ROS Toolbox. I found that there are several ROS installations, so, could you please kindly help and support? Hoping that your support will help a lot to my master's thesis.
i want make web site for pre registation to the vachile in thish project i can not thinke how to register in port and how to make .....????
Harshita
Harshita
Last activity on 6 Sep 2023

Hi! Actually I'm trying to store data from 5 sensors on the ThingSpeak cloud. I was able to do it 2-3 days back, but right now I'm trying to do the same for last 2-3 hours and it's just not happening. There's nothing wrong with the code because it's getting compiled properly. I'm using
ThingSpeak.writeFields(2261556,"xxxxxxxxxxxxxxxx");
I tried printing its value after storing in a temporary variable........The value comes out to be -301. Is there any fix for this? I need it urgently for a project.
I hope to receive some help soon. Thanks!
% Sample data from channels
channel1Data = 2226948; % Your data for channel 1
% Threshold values for each alert level
threshold1 = 100;
threshold2 = 200;
threshold3 = 300;
% Initialize alert level to 0 (no alert)
alertLevel = 0;
% Check thresholds and determine alert level
if channel1Data >= threshold1 && channel1Data <= threshold2
alertLevel = 1; % Yellow Alert
elseif channel1Data >= threshold2 && channel1Data <= threshold3
alertLevel = 2; % Orange Alert
elseif channel1Data >= threshold3
alertLevel = 3; % Red Alert
end
% Define alert message based on alert level
if alertLevel == 1
alertMessage = 'Threshold exceeded for channel 1!';
elseif alertLevel == 2
alertMessage = 'Threshold exceeded for channel 2!';
elseif alertLevel == 3
alertMessage = 'Threshold exceeded for channel 3!';
else
alertMessage = 'No alert for channel 1.';
end
% Call SMS integration function with the alert message
sendMessage('+639319217695', alertMessage);
function sendMessage(number, message)
% Replace with your SMS service API endpoint and API key
apiUrl = 'https://api.semaphore.co/api/v4/messages';
apiKey = '-----';
% Compose the message payload
payload = struct('apikey', apiKey, 'number', number, 'message', message);
try
% Send the SMS using the SMS service API
response = webwrite(apiUrl, payload);
% Process the response as needed
disp('SMS sent successfully');
catch
disp('Error sending SMS');
end
end
I've just bought a rain gauge with esp 32 but the problem is Its code is already programmed on esphome
Now I need to send the data to one of my channels so I can perform the logic for my sms API
Tell me if it's possible
Hi
We are using Raspberry Pi to send some sensor data to Thingspeak. Is it possible to send this data to any other IoT hub service lets say Thingsboard, AWS or Azure IoT hub? Does Thingspeak provide any kind of API which can give us alerts whenever the data is received in Thingspeak server ?
Thanks