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Dear all,
in the Matlab Analysis I use twice the fuinction thingSpeakRead to read data from a channel, from two different fields.
The problem is that so far, only one of the values is read properly and the other one delivers NaN.
What could be the reason?
Thank you!
Here's my code:
% TODO - Replace the [] with channel ID to read data from:
readChannelID = [xxx];
% TODO - Enter the Read API Key between the '' below:
readAPIKey = 'xxxxxxxx';
% TODO - Replace the [] with channel ID to write data to:
writeChannelID = [xxx];
% TODO - Enter the Write API Key between the '' below:
writeAPIKey = 'xxxxxx';
%% Read Data %%
%data = thingSpeakRead(readChannelID, 'ReadKey', readAPIKey);
temperature = thingSpeakRead(xxx,Fields=[1])
humidity = thingSpeakRead(xxx,Fields=[8])
Hello I want to upload a single value from a raspberry and I can't find a way. Can somebody help me?
Lot of Thanks¡¡
TimeControl Ran, but it didn't appiied it to channel (chart has not been updated in the right time and in the end, it did not ran, had to manually run the script by myself). And I would like to request to MathWorks to fix (modify) my chart to right time and value and investigate this problem.
I want to control the level my water tank with a esp8266 and Thingspeak.
I can see the level in Thingspeak. This is working.
Now I want to send 2 emails :
- One daily email with the actual level
- Alarm email when level is below a setpoint.
How can I incorporate the value from a channel in the email ?
What I have now for the daily email , but with errors :
alert_body = 'huidig peil regenput';
channelID = ..........;
% Provide the ThingSpeak alerts API key. All alerts API keys start with TAK.
alertApiKey = 'TAK...............';
% Set the address for the HTTTP call
alertUrl="https://api.thingspeak.com/alerts/send";
% webwrite uses weboptions to add required headers. Alerts needs a ThingSpeak-Alerts-API-Key header.
options = weboptions("HeaderFields", ["ThingSpeak-Alerts-API-Key", alertApiKey ]);
% Set the email subject.
alertSubject = sprintf("Niveau regenput " );
% Read the recent data.
peil = thingSpeakRead(channelID,'Fields',1);
% Check to make sure the data was read correctly from the channel.
% Set the outgoing message
webwrite(alertUrl , "body", alertBody, "subject", alertSubject,'Fields',peil);
% Catch errors so the MATLAB code does not disable a TimeControl if it fails
try
webwrite(alertUrl , "body", alert_body, "subject", alertSubject, options);
catch someException
fprintf("Failed to send alert: %s\n", someException.message);
end
The errors I receive :
Unrecognized function or variable 'alert_Body'.
Error in Read Channel to Trigger Email 1 (line 24)
webwrite(alertUrl , "body", alert_Body, "subject", alertSubject,"Fields",peil);
Manny thanks in advance
Hallo,
ich Neuling hier, und habe das Beispiel WriteMultipleFields benutzt um die Funktionsweise zu verstehen.
So weit so gut, hat auch alles grklappt. Jetzt nach 2 Tagen bekomme ich immer eine Fehlermeldung.
Problem updating channel. HTTP error code -401 abwechselnd mit
Channel update successful.
Es ist immernoch die gleiche Software, Board ist WiFi LoRa 32 V3.
Buongiorno, non mi è possibile connetermi al canale di thingspeak che ho creato, per passare i dati tramite MQTT. Il codice segue la libreria PubSubClient su arduino ide, l'errore restituito dal serial monitor dell'ide é: -4 : MQTT_CONNECTION_TIMEOUT - the server didn't respond within the keepalive time.
Allego il codice per eventuali verifiche:
Grazie per a disponibilità
#include "PubSubClient.h"
#include <ESP8266WiFi.h>
#include "secrets.h"
bool DEBUG = false; // true=serial message of debug enabled
char* server = "mqtt.thingspeak.com";
WiFiClient wifiClient;
PubSubClient client(server, 1883, wifiClient);
String payload;
// BME280 Setting
#include <Wire.h>
#include <Adafruit_BME280.h>
//#define SEALEVELPRESSURE_HPA (1013.25)
Adafruit_BME280 bme; // I2C
bool BMEStatus;
ADC_MODE(ADC_VCC); // Set ADC for read Vcc
// Update time in seconds. Min with Thingspeak is ~20 seconds
const int UPDATE_INTERVAL_SECONDS = 3600; //il clock interno ha un errore del 5% questo valore va tarato sperimentalmente
//const int UPDATE_INTERVAL_SECONDS = 60; // caricamento ogni minuto solo per test
void setup()
{
// Connect BME280 GND TO pin14 OR board's GND
pinMode(14, OUTPUT);
digitalWrite(14, LOW);
Serial.begin(115200);
delay(10);
// BME280 Initialise I2C communication as MASTER
Wire.begin(13, 12); //Wire.begin([SDA], [SCL])
BMEStatus = bme.begin();
if (!BMEStatus)
{
if (DEBUG) { Serial.println("Could not find BME280!"); }
//while (1);
}
// Weather monitoring See chapter 3.5 Recommended modes of operation
bme.setSampling(Adafruit_BME280::MODE_FORCED,
Adafruit_BME280::SAMPLING_X1, // temperature
Adafruit_BME280::SAMPLING_X1, // pressure
Adafruit_BME280::SAMPLING_X1, // humidity
Adafruit_BME280::FILTER_OFF );
// read values from the sensor
float temperature, humidity, pressure;
if (BMEStatus)
{
temperature = bme.readTemperature();
humidity = bme.readHumidity();
pressure = bme.readPressure() / 100.0F;
}
else
{
if (DEBUG) Serial.println("Could not find BME280!");
temperature=0;
humidity=0;
pressure=0;
}
float voltage = ESP.getVcc();
voltage = voltage/1024.0; //volt
if (DEBUG)
{
Serial.println("T= " + String(temperature) + "°C H= " + String(humidity) + "% P=" + String(pressure) + "hPa V=" + voltage + "V");
}
// Construct MQTT payload
payload="field1=";
payload+=temperature;
payload+="&field2=";
payload+=humidity;
payload+="&field3=";
payload+=pressure;
payload+="&field4=";
payload+=voltage;
payload+="&status=MQTTPUBLISH";
//Connect to Wifi
if (DEBUG)
{
Serial.println();
Serial.print("\nConnecting to WiFi SSID ");
Serial.print(SECRET_SSID);
}
WiFi.begin(SECRET_SSID, SECRET_PASS);
int timeOut=10; // Time out to connect is 10 seconds
while ((WiFi.status() != WL_CONNECTED) && timeOut>0)
{
delay(1000);
if (DEBUG) { Serial.print("."); }
timeOut--;
}
if (timeOut==0) //No WiFi!
{
if (DEBUG) Serial.println("\nTimeOut Connection, go to sleep!\n\n");
ESP.deepSleep(1E6 * UPDATE_INTERVAL_SECONDS);
}
if (DEBUG) // Yes WiFi
{
Serial.print("\nWiFi connected with IP address: ");
Serial.println(WiFi.localIP());
}
// Reconnect if MQTT client is not connected.
if (!client.connected())
{
reconnect();
}
mqttpublish();
delay(200); // Waiting for transmission to complete!!! (ci vuole)
WiFi.disconnect( true );
delay( 1 );
if (DEBUG) { Serial.println("Go to sleep!\n\n"); }
// Sleep ESP and disable wifi at wakeup
ESP.deepSleep( 1E6 * UPDATE_INTERVAL_SECONDS, WAKE_RF_DISABLED );
}
void loop()
{
//there's nothing to do
}
void mqttpublish()
{
// read values from the sensor
float temperature, humidity, pressure;
if (DEBUG)
{
Serial.print("Sending payload: ");
Serial.println(payload);
}
// Create a topic string and publish data to ThingSpeak channel feed.
String topicString ="channels/" + String( channelID ) + "/publish/"+String(writeAPIKey);
unsigned int length=topicString.length();
char topicBuffer[length];
topicString.toCharArray(topicBuffer,length+1);
if (client.publish(topicBuffer, (char*) payload.c_str()))
{
if (DEBUG) Serial.println("Publish ok");
}
else
{
if (DEBUG) Serial.println("Publish failed");
}
}
void reconnect()
{
String clientName="MY-ESP";
// Loop until we're reconnected
while (!client.connected())
{
if (DEBUG) Serial.println("Attempting MQTT connection...");
// Try to connect to the MQTT broker
if (client.connect((char*) clientName.c_str()))
{
if (DEBUG) Serial.println("Connected");
}
else
{
if (DEBUG)
{
Serial.print("failed, try again");
// Print to know why the connection failed.
// See http://pubsubclient.knolleary.net/api.html#state for the failure code explanation.
Serial.print(client.state());
Serial.println(" try again in 2 seconds");
}
delay(2000);
}
}
}
Quick answer: Add set(hS,'Color',[0 0.4470 0.7410]) to code line 329 (R2023b).
Explanation: Function corrplot uses functions plotmatrix and lsline. In lsline get(hh(k),'Color') is called in for cycle for each line and scatter object in axes. Inside the corrplot it is also called for all axes, which is slow. However, when you first set the color to any given value, internal optimization makes it much faster. I chose [0 0.4470 0.7410], because it is a default color for plotmatrix and corrplot and this setting doesn't change a behavior of corrplot.
Suggestion for a better solution: Add the line of code set(hS,'Color',[0 0.4470 0.7410]) to the function plotmatrix. This will make not only corrplot faster, but also any other possible combinations of plotmatrix and get functions called like this:
h = plotmatrix(A);
% set(h,'Color',[0 0.4470 0.7410])
for k = 1:length(h(:))
get(h(k),'Color');
end
How to Simulate a Synchronous Compensator in Simulink?
I have been having problems sending ThingSpeak alerts so I created a simple routine that demonstrates the problem. The code executes successfully but I never receive an email with the alert. What am I doing wrong?
% Set Thingspeak address, alerts API key, and options for the HTTTP call
alertUrl = "https://api.thingspeak.com/alerts/send";
alertApiKey = "TAKxxxxxxxxxxxxxxxx";
options = weboptions("HeaderFields",["ThingSpeak-Alerts-API-Key",alertApiKey]);
% Set content for email subject and body.
alertSubject = "ThingSpeak Alert Subject";
alertBody = "ThingSpeak Alert Body";
% Catch errors so the MATLAB code does not disable a TimeControl if it fails
try
webwrite(alertUrl, "body", alertBody, "subject", alertSubject, options);
catch Exception
fprintf("Failed to send alert: %s\n", Exception.message);
end
Am running multiple sensors in the field producing strings of data then sending them to a node. The node is an Arduino Uno on which SIM 800 is attached for internet connectivity. After computation, the result is several strings that i want to display to things speak. The code i have so far can only upload numerical data. Am in need of help to display these strings in Thingsspeak.Help me.
Dear Team,
I have populated my data on ThingsBoard platform using ESP8266, now I want to read that data using MATLAB Industrial Communication Toolbox. I have written a code for this purpose below,
% Replace these values with your ThingsBoard MQTT broker details
brokerAddress = "ssl://demo.thingsboard.io"; % Adjust the broker address
port = 1883; % Use the appropriate port for secure MQTT
% Replace these values with your ThingsBoard device details
clientID = "";
userName = "";
password = ""; % Leave empty if not required
% Replace this with the path to the root certificate you downloaded
rootCert = "";
% Create an MQTT client
mqClient = mqttclient(brokerAddress, 'Port', port, 'ClientID', clientID, ...
'Username', userName, 'Password', password, 'CARootCertificate', rootCert);
% Check if the connection is established
mqClient.Connected
% Expected output: ans = int32(1)
% Subscribe to the telemetry topic
topicToSub = "v1/devices/me/telemetry";
subscribe(mqClient, topicToSub);
% Wait for a while to receive messages (adjust the time as needed)
pause(60);
% Peek at the MQTT client to view received messages
peek(mqClient);
% Close the MQTT client
clear mqClient;
%%%%__________________Output Result______________________%%%%%
>> MQTT_Receive
Warning: Using a port that allows unencrypted communication. For confidential matters, considering using an encryption
enforcing port, such as 8883.
Error using MQTT_Receive
Failed to establish a connection with broker "ssl://demo.thingsboard.io".
I desperately seeking your assistance in this regard
I'm logging data which I'd like to see on a daily basis. ie each day the chart x axis resets to 12midnight to 12midnight for the current day and just shows todays data. Is this possible please ?
Hello
I have been using ThingSpeak for about 2 years with no problems. I am observing sensor data and connecting widgets to some of the values. Since yesterday, there are some of the widgets that send blank values. Have you changed something?
Thank you
Hello, all!
This is my first post after just joining this discussion, so please forgive me and provide kind assistance if I have posted to the wrong subsection!
I have a good interest in learning sql server course and right now I am taking help from various platforms like https://www.coursera.org/ https://www.udemy.com/
Also I have a doubt that is it a good option to learn from platforms like this or I should go for some sql server online training . I have searched for the solution of my queries in various above platforms which helped me up to some extent only as it was not directly given by any expert or trainer.
Hoping in getting a quick response
Thankyou in advance.
Hello, I am a student and I am working on a neural network for a line follower car and I would like you to recommend a tutorial to implement it in simulink.
Hello, I would like to send temperature and humidity data from my ThingSpeak channel to the https://www.wunderground.com/ service. I managed to configure the initial connection through ThingHTTP, and on the WeatherUnderground website, there is information about data updates, but there are no actual values: https://www.wunderground.com/dashboard/pws/IKORON5/table/2023-11-19/2023-11-19/daily
I don't know how to correctly configure all the options in ThingHTTP and in the Apps - React section.
I think it would be a really great feature to be able to add an Alpha property to the basic "Line" class in MATLAB plots. I know that I have previously had to resort to using Patch to be able to plot semitransparent lines, but there are also so many other functions that rely on the "Line" class.
For example, if you want to make a scatter plot from a table with things specified into groups, you can use ScatterHistogram or gscatter but since gscatter uses the Line class, you can't adjust the marker transparency. So if you don't want the histograms, you are stuck with manually separating it and using scatter with hold on.
Hi Guys
Posting this based on a thought I had, so I don't really ahve any code however I would like to know if the thought process is correct and/or relatively accurate.
Consider a simple spring mass system which only allows compression on the spring however when there is tension the mass should move without the effect of the spring distrupting it, thus the mass is just thrown vertically upwards.
The idea which I came up with for such a system is to have two sets of dfferential equations, one which represents the spring system and another which presents a mass in motion without the effects of the spring.
Please refer to the below basic outline of the code which I am proposing. I believe that this may produce relatively decent results. The code essentially checks if there is tension in the system if there is it then takes the last values from the spring mass differential equation and uses it as initial conditions for the differential equation with the mass moving wothout the effects of the spring, this process works in reverse also. The error which would exist is that the initial conditions applied to the system would include effects of the spring. Would there be a better way to code such behaviour?
function xp = statespace(t,x,f,c,k,m)
if (k*x(1)) positive #implying tension
**Use last time step as initial conditions**
**differential equation of a mass moving""
end
if x(1) negative #implying that the mass in now moving down therefore compression in spring
**Use last time step as initial conditions**
**differential equation for a spring mass system**
end
end
when I examine the data stream on an arduino ide I get a lot of "stuff" which I dont understand.
1 what does it mean?
2 how do I prevent it?
Seeing a colleague make this mistake (one I've had to fix multiple times in other's work too) makes me want to ask the community: would you like the awgn() function/blocks to give the option for creating a SNR at the bandwidth of the signal? Your typical flow is something like this:
- Create a signal, usually at some nominal upsampling factor (e.g., 4) such that it's now nicely over sampled, especially if you're using a RRC or similar pulse shaping filter.
- Potentially add a frequency offset (which might make the sample frequency even higher)
- Add AWGN channel model for a desired SNR
- Put this into your detector/receiver model
The problem is, when someone says, "I'm detecting XYZ at foo SNR," it should not magically improve as a function of the oversample. The problem isn't that awgn() generates white noise, that's what it's supposed to do and the typical receiver has noise across the entire band. The problem is that SNR is most properly defined as the signal power over the noise power spectral density times the signal's noise equivalent bandwidth. Now I looked and there's no handy function for computing NEBW for an input signal (there's just a function for assessing analysis windows). In practice it can get a bit tricky. The occupied bandwidth or HPBW are often close enough to the NEBW, we're usually not haggling over hundredths of a dB. So, in my not so humble opinion, the "measured" flag for awgn() should give an option for bandwidth matching or at least document the behavior better in the help page. All too often I'm seeing 3-6 (or worse) dB errors because people aren't taking the signal's bandwidth into account.
