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I would like a free account on Thingspeak for 1 device/channel using lorawan and < 300 messages a day for non-commercial (home) use. Today I received an email from MathWorks that my trial period ends. Somewhere I read I may have indicated commercial usage when starting the Thingspeak account. But I cannot find it in Thingspeak profile, nor in my Mathworks profile. How to change this?

El termómetro quedo tildado en -127°, lo desconecte en varias oportunidades y se encuentra tildado.

Hello! A few years ago i could write data to my thingspeak field with this code on arduino with ESP8266.

However today when i try this i only get errors. Instead I have to use this code. it is almost the same but connecting without SSL on port 80 instead.

Has anything changed on thingspeaks side? What do i do wrong? Here is a link to the full code if thats needed: https://github.com/kjellcompany/Arduino_701/blob/master/Thingspeak/Thingspeak.ino

Every day, thousands of people ask questions on MATLAB Answers and many of these are about their code. Questions such as “How can I make this faster?”, “Why do I get this error message?” or “Why don’t I get the answer I expect?”. There’s often one crucial thing missing though – the code in question!

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General web search
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813 votes
Ray B
Ray B
Last activity on 6 Jan 2022

Recently, 2nd Jan 2022 my logging has stopped. In My Account I see I have an expiry date of 10/Jan/2022 could this be the cause??? Specifically does a Free Account eventually expire and besides paying for a student or Home account is there anything I can do to continue using ThingSpeak at no charge? My message count is well below the maximum of 3 million per year.

I'm trying to solve one problem in Cody, but a function 'fmincon' is not recognized by the online compiler. Is there any way to use functions in optimization toolbox in Cody?

Bonjour, J'utilise arduino Mega 2560 avec le shield Ethernet. Le sketch ino joint ci-après me permet de visualiser la jauge dans la page index.htm chargée sur la carte SD. ThingSpeak affiche bien le graph correspondant. Mais ma page web n'y a pas accès. Comment intégrer les codes dans la page ou dans le sketch pour cela ? Je vous joins la capture d'écran de cette page ainsi que les codes De la page et du sketch. Merci pour votre aide.

*********************************** Code Page "index.htm" ***********************************

<!DOCTYPE html>
<html>
    <head>
        <title>Arduino Internet Voltmeter</title>
        <script>
		var data_val = 0;		// raw data from Arduino analog input (0 to 1023)
		var volts = 0;			// voltage calculated from Arduino analog raw data value
		var num_updates = 0;	// number of 200ms periods used to calculate time to send data to ThingSpeak
		// gauge code
		eval(function(p,a,c,k,e,r){e=function(c){return(c<a?'':e(parseInt(c/a)))+((c=c%a)>35?String.fromCharCode(c+29):c.toString(36))};if(!''.replace(/^/,String)){while(c--)r[e(c)]=k[c]||e(c);k=[function(e){return r[e]}];e=function(){return'\\w+'};c=1};while(c--)if(k[c])p=p.replace(new RegExp('\\b'+e(c)+'\\b','g'),k[c]);return p}('t W=v(f){W.2t.3T(A);A.B={Z:2u,19:1q,1h:1q,1J:U,1b:D,K:0,V:[\'0\',\'20\',\'40\',\'2A\',\'2B\',\'D\'],2r:10,2C:M,1E:U,2q:{2D:3,2E:2},2H:M,1c:{2j:10,2m:3y,2O:\'3v\'},J:{2P:\'#4h\',V:\'#31\',2r:\'#3k\',1J:\'#37\',1E:\'#37\',3e:\'#31\',1t:{2s:\'1e(3Y, 3d, 3d, 1)\',3c:\'1e(1Y, 5I, 5E, .9)\'}},1o:[{1n:20,1D:2A,1F:\'#3j\'},{1n:2A,1D:2B,1F:\'#36\'},{1n:2B,1D:D,1F:\'#5n\'}]};t g=0,1p=A,N=0,1S=0,1G=U;A.5d=v(a){N=f.1c?g:a;t b=(f.1b-f.K)/D;1S=a>f.1b?1S=f.1b+b:a<f.K?f.K-b:a;g=a;f.1c?3l():A.1g();C A};A.3m=v(a){N=g=a;A.1g();C A};A.4T=v(){g=N=1S=A.B.K;A.1g();C A};A.4R=v(){C g};A.13=v(){};v 2k(a,b){Q(t i 4P b){z(1H b[i]=="1W"&&!(4O.4y.2V.4p(b[i])===\'[1W 4n]\')&&i!=\'Z\'){z(1H 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		// function called periodically to get analog value from Arduino using Ajax
		function GetArduinoInputs()
		{
			nocache = "&nocache=" + Math.random() * 1000000;
			var request = new XMLHttpRequest();
			request.onreadystatechange = function()
			{
				if (this.readyState == 4) {
					if (this.status == 200) {
						if (this.responseXML != null) {
							document.getElementById("input3").innerHTML =
								this.responseXML.getElementsByTagName('analog')[0].childNodes[0].nodeValue;
								data_val = this.responseXML.getElementsByTagName('analog')[0].childNodes[0].nodeValue;
								// calculate voltage
								volts = data_val * 3.5 / 1023;
								// only send data to ThingSpeak every 20 seconds or 100 x 200ms
								if (num_updates >= 100) {
									num_updates = 0;
									// send voltage to ThingSpeak
								ThingSpeakSend("xxxxxxxxxxxxxxxx", volts);	// insert your ThingSpeak Write API Key here
								
								}
								num_updates++;
						}
					}
				}
			}
			request.open("GET", "ajax_inputs" + nocache, true);
			request.send(null);
			setTimeout('GetArduinoInputs()', 200);	// send the request for Arduino analog data every 200ms
			
		}
		// function to send data to ThingSpeak
		function ThingSpeakSend(api_write_key, voltage)
		{
			var ts_req = new XMLHttpRequest();
			// GET request string - modify if more fields are needed
			var req_str = "http://api.thingspeak.com/update?key=" + api_write_key + "&field1=" + voltage;
			ts_req.onreadystatechange = function()
			{
				// not doing anything with response from ThingSpeak
			}
			// send the data to ThingSpeak
			ts_req.open("GET", req_str, true);
			ts_req.send(null);
		}
	</script>
    </head>
    <body onload="GetArduinoInputs()">
        <h1>Arduino Internet Voltmeter</h1>
        <p>Analog (A2): <span id="input3">...</span></p>
        <canvas id="an_gauge_1" data-major-ticks="0 0.5 1 1.5 2 2.5 3 3.5" data-type="canv-gauge" data-min-value="0" data-max-value="3.5" data-onready="setInterval( function() { Gauge.Collection.get('an_gauge_1').setValue(volts);}, 200);"></canvas>
        <!-- insert ThingSpeak chart code here -->
          <iframe width="450" height="260" style="border: 1px solid #cccccc;" src="https://thingspeak.com/channels/1620920/charts/1?bgcolor=%23ffffff&color=%23d62020&dynamic=true&results=60&type=line&update=20&yaxismax=4&yaxismin=0"></iframe>
  <!-- REPLACE THIS COMMENT WITH YOUR THINGSPEAK GRAPH -->
      </body>
  </html>

********************************************* Code "eth_websrv_SD_Ajax_gauge.ino" : *********************************************

#include <Ethernet.h>
#include <SD.h>
#include <ThingSpeak.h>
// size of buffer used to capture HTTP requests
#define REQ_BUF_SZ   50
// MAC address from Ethernet shield sticker under board
byte mac[] = { 0x90, 0xA2, 0xDA, 0x00, 0x1A, 0x71 };
IPAddress ip(192, 168, 1, 17); // IP address, may need to change depending on network
EthernetServer server(80);  // create a server at port 80
File webFile;               // the web page file on the SD card
char HTTP_req[REQ_BUF_SZ] = {0}; // buffered HTTP request stored as null terminated string
char req_index = 0;              // index into HTTP_req buffer
void setup()
{
  // disable Ethernet chip
  pinMode(10, OUTPUT);
  digitalWrite(10, HIGH);
    Serial.begin(9600);       // for debugging
    // initialize SD card
    Serial.println("Initializing SD card...");
    if (!SD.begin(4)) {
        Serial.println("ERROR - SD card initialization failed!");
        return;    // init failed
    }
    Serial.println("SUCCESS - SD card initialized.");
    // check for index.htm file
    if (!SD.exists("index.htm")) {
        Serial.println("ERROR - Can't find index.htm file!");
        return;  // can't find index file
    }
    Serial.println("SUCCESS - Found index.htm file.");
    Ethernet.begin(mac, ip);  // initialize Ethernet device
    server.begin();           // start to listen for clients
    Serial.print ("*\n -> Le serveur est sur l'adresse : ");
    Serial.println(Ethernet.localIP());
}
void loop()
{
    EthernetClient client = server.available();  // try to get client
    if (client)   // got client?
        {
          boolean currentLineIsBlank = true;
        while (client.connected()) 
        {
            if (client.available())    // client data available to read
                {
                char c = client.read(); // read 1 byte (character) from client
                // buffer first part of HTTP request in HTTP_req array (string)
                // leave last element in array as 0 to null terminate string (REQ_BUF_SZ - 1)
                if (req_index < (REQ_BUF_SZ - 1)) {
                    HTTP_req[req_index] = c;          // save HTTP request character
                    req_index++;
                }
                // last line of client request is blank and ends with \n
                // respond to client only after last line received
                if (c == '\n' && currentLineIsBlank) {
                    // send a standard http response header
                    client.println("HTTP/1.1 200 OK");
                    // remainder of header follows below, depending on if
                    // web page or XML page is requested
                    // Ajax request - send XML file
                    if (StrContains(HTTP_req, "ajax_inputs")) {
                        // send rest of HTTP header
                        client.println("Content-Type: text/xml");
                        client.println("Connection: keep-alive");
                        client.println();
                    // send XML file containing input states
                    XML_response(client);
                    }
                    else {  // web page request
                        // send rest of HTTP header
                        client.println("Content-Type: text/html");
                        client.println("Connection: keep-alive");
                        client.println();
                        // send web page
                        webFile = SD.open("index.htm");        // open web page file
                        if (webFile) {
                            while(webFile.available()) {
                                client.write(webFile.read()); // send web page to client
                            }
                            webFile.close();
                        }
                    }
                    // display received HTTP request on serial port
                    Serial.print(HTTP_req);
                    // reset buffer index and all buffer elements to 0
                    req_index = 0;
                    StrClear(HTTP_req, REQ_BUF_SZ);
                    break;
                }
                // every line of text received from the client ends with \r\n
                if (c == '\n') {
                    // last character on line of received text
                    // starting new line with next character read
                    currentLineIsBlank = true;
                } 
                else if (c != '\r') {
                    // a text character was received from client
                    currentLineIsBlank = false;
                }
            } // end if (client.available())
        } // end while (client.connected())
        delay(1);      // give the web browser time to receive the data
        client.stop(); // close the connection
    } // end if (client)
}
// send the XML file containing analog value
void XML_response(EthernetClient cl)
{
    int analog_val;
      cl.print("<?xml version = \"1.0\" ?>");
      cl.print("<inputs>");
      // read analog pin A2
      analog_val = analogRead(2);
      cl.print("<analog>");
      cl.print(analog_val);
      cl.print("</analog>");
      cl.print("</inputs>");
  }
// sets every element of str to 0 (clears array)
void StrClear(char *str, char length)
{
    for (int i = 0; i < length; i++) {
        str[i] = 0;
    }
}
// searches for the string sfind in the string str
// returns 1 if string found
// returns 0 if string not found
char StrContains(char *str, char *sfind)
{
    char found = 0;
    char index = 0;
    char len;
    len = strlen(str);
    if (strlen(sfind) > len) {
        return 0;
    }
    while (index < len) {
        if (str[index] == sfind[found]) {
            found++;
            if (strlen(sfind) == found) {
                return 1;
            }
        }
        else {
            found = 0;
        }
        index++;
    }
      return 0;
  }

My dear friend Ram and I have finished our latest movie series. You can watch the final movie , or see the whole series.

In this movie we show how you can use TimeControls and Reacts to control devices or to schedule your MATLAB code that you can write in ThingSpeak. We also discuss a bit about channel sharing.

Hi,

I am new to Matlab and looking to model complete EPS system starting with battery modelling. I have seen videos where the modelling is explained but looking for a one which can teach me from the scratch.

Kaizer 1419
Kaizer 1419
Last activity on 26 Dec 2021

Is it possible to use the REST API to create ThingHTTP requests?

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Hi Everyone,

Today mistakenly i clear the working channel instead of testing channel which have more then 27000 Environmental Sensor readings so is there any option where i can get back my that data?

Thank you.

Image Analyst
Image Analyst
Last activity on 7 Apr 2022

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Hi!

I'm trying to use a mix of Arduino Nano + SIM800L + RTC DS3231 + 2x PZEM-004T to achieve the goal of upload the two Energy readings every 24h to Thingspeak channel. My sketch is this https://pastebin.com/a6Zn8HaV, i'm in doubt if the use of String class for the GET job is correct.

Could you help me?

Thanks

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