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Hello, I am currently working on a simple android app for a smart irrigation system. Basically the app lets the user enter the name of the plant and then lists all the plants of the garden. Then, I have divided plants into three categories depending on their watering needs and I have created three int values for the amount of plants per group. Essentially I want to send these three values to a thingspeak channel I created, to 3 separated fields. I am not familiar at all with server programming in Java so I would really appreciate any kind of help in how to do this.

Can not pick just a single field for "No data check", just the whole channel. Is there any way to change?

I have a datasheet of an induction motor (as figure below). I want to simulate it on matlab/simulink, but I don't know it's parameters (Lls, Llr, Lm, Rr, Rs).

I tried to search about open circuit test and blocked rotor test to determine these parameters, but some of information doesn't appear on datasheet and I don't have the real motor to test on it (datasheet is only think I have).

Could someone help me with this?

I have a personal account which I use for my home projects, along with a paid license which I use for monitoring a set of sensors in a remote building.

All my sensors went offline at about the same time, but I am only just noticing this now, because I have been focused on why the remote location went offline, thinking that it was an issue with the internet or WiFi at that location, rather than a problem with posting the data!

All my monitoring setups are using electricImp devices to post data to ThinkSpeak and have been in some cases, running for several years without any issues. All the devices are now returning a 400 - invalid constant string error.

See logs below.

|2022-04-19T13:30:07.017 +00:00	[Agent]	https://api.thingspeak.com/update?api_key=XXXXXXX&status=OK&created_at=2022-04-19 13:30:01 UTC&field4=0.00&field3=0.00&field6=0.00&field5=0.00&field2=14.65&field1=2022-04-19%2013%3A30%3A01%20UTC&status=OK&field8=0.6129&field7=0.00&created_at=2022-04-19%2013%3A30%3A01%20UTC
    2022-04-19T13:30:07.086 +00:00	[Agent]	PUSH: 400 - invalid constant string

I modified a device to not send the date in field 1 on one device because I thought that might be causing the problem, but it is not clear to me what changed. I have been sending data like this for a long time.

Any ideas appreciated.

Thanks

Hi... I managed to work out both the pub & sub parts of MQTT with my esp8266. I did the example from over here ... and all works fine. The publishing happens every 15secs... and it received the published values back almost immediately. see Img1.png

Now using flutter from my mobile app I did the same thing... and I was able to pub & sub... and also checked the Field1 values in my Thingspeak account that i am writing to and reading as an MQTTclient. It all works correctly.

HOWEVER... heres the problem================ When I only publish from the mobile a value for Field1. And subscribing at the same time from my esp8266 to receive the updated value of Field1... something weird happens... My Field1 in the channel, in my Thingspeak account has been updated correctly... but my esp8266 doesnt receive the updated value. INSTEAD, at the same time I can see in the serial monitor logs, the esp8266 reconnects back to our MQTT server!! No update was received. It felt as if everytime I published a value from my mobile, it made my esp8266 disconnect and hence it needed to reconnect to the MQTT server. i checked this 10 times and it happened without a coincidence. I ran the same code on the esp8266, except that I never let it publish every 15secs. So all it did was stay subscribed and await an update from my mobile app. please see img2.png

and this is the flutters connection code

 client.logging(on: false);
    client.setProtocolV311();
    client.keepAlivePeriod = 10;
    client.onDisconnected = onDisconnected;  //....callbacks
    client.onConnected = onConnected;  //....callbacks
    client.pongCallback = pong;  //....callbacks

    final connMess = MqttConnectMessage()
        .withClientIdentifier('xxxxxxxxxxxxxxxx')
        .withWillTopic('willtopic') // If you set this you must set a will message
        .withWillMessage('My Will message')
        .startClean() // Non persistent session for testing
        .authenticateAs('xxxxxxxxxxxxxxxx', 'aaaaaaaaaaaa')
        .withWillQos(MqttQos.atMostOnce); // means = 0
    print('client connecting....');

Any help will be appreciated. Just wanted to iterate that individually they both work fine. Just that i need the updated value... and i dont receive it. Any ideas?? thanks, YOhan

Hi! As the title says, I want to group the data readings from multiple fields and channels into a single formatted tweet. Kinda of like a status report tweet for a few different sensors I have running. Is this possible? My current understanding of the MATLAB analysis/react is that it can only do 1 field at most. Any help would be greatly appreciated by this stresses out college senior :)

I have a Thingtweet: "Measurements %%datetime%% Comment" The tweet will send the time as say: 5:23pm I want it in 24hr format = 17:23 I have scoured the site and I cant find any way of doing this in a tweet. Also that would be local time, is it possible to use UTC ?

Hello guys, I'm a new Thingspeak user and I don't know how can I filter a numbers from a data string using the ThingHTTP application or MPLAB Analysis. The data string it's come from a power meter and the structure is like below: {"data":{"values":[[249.000,0.370, 30.000,0.532,0.001],[246.400,0.290, 6.000,0.088,0.000][240.900,0.640, 77.000,0.526,0.000]],"localTime":"2022/3/25 1:30:38","gmtTime":"2022/3/24 23:30:38"},"successful":true,"message":null}.

So, I need to extract only the numbers that represents the instant power on each phase (bolded numbers). When I tried to use the MPLAB Analysis - get data from a webpage, but the filter it return "2022" number.

I also try to use the ThingHTTP, I managed to display the entire data string (like above), but I can't filter them. If I select the numbers that interest me and right click on this to inspect the element, I saw that the entire string is stored as single element.

Can you offer me any suggestion to filter only one number an dafter that to make a graph in Thingspeak?

Thanks a lot in advance!

Is it possible to get a "Handshake" back from the server to acknowledge receipt of a data packet ? I want to drive Red/Green LED - Red for Sent followed by Green if receipt is confirmed. I have an ESP32 project sending data without problems, unknown to me the internet connection had been lost, but I had no indication anything was wrong.

Hi everyone, is there any problem with the Thingspeak MQTT broker right now? This is the error message I keep seeing in the terminal window using node-RED.

[info] [mqtt-broker:ThingSpeak MQTT Broker] Connection failed to broker: mqtt://mqtt.thingspeak.com:1883

And on the gui, the mqtt-in node is perpetually in "connecting.." state.

I tested some weeks ago and it was working fine. Now it doesn't work. I have asked my students to make a simple project using the MQTT protocol and now they can't proceed, I don't understand why.

I've had a Thingspeak channel since 2017. It's updated by a RPi running Raspbian Lite (the Raspberry Pi version of Debian Linux). The "Lite" means there's not much GUI stuff in there, and the RPi is run "headless" using SSH. To update my channel I use the linux utility curl to send http GET commands. curl is run at intervals from a bash script which loops indefinitely.

This has worked fine for nearly 5 years until suddenly between 14:00 and 14:20 UTC on 13/4/22 (UK format) it stopped working, and I started getting HTTP error 400 responses. I haven't changed anything; I haven't updated the RPi OS for over a year, and the timestamp the bash script file is 2020.

Status is enabled on the channel, and a little trial and error showed that the problem was caused by including a status update string which contained a space character. So the workaround is simple, just amend the status string to not have a space character, and all is well again.

I can still send status updates with a string including a space character directly from a web browser, so what has happened to break curl after all this time?

Hello, today my Python script is giving error messages "There was an error while publishing the data". It is an existing script that runs for a couple of years already. My local network, Wifi, ... is OK. Rebooting Pi does not help. Is there maybe an issue on the Thingspeak servers ? Kind regards, Patrick (Belgium).

Hi, Its my day 1... and just thought i should confirm something for sake of clarity. I found this table on the site...

But I want to know does Number of Messages include Reads & Writes... or only Writes because the other parameter is Message update interval limit ... and usually the word update is a part of the operation where there is a WRITE being committed. And thats what confused me...

So is that interval only for updating data... or is it even if you are reading data?

Thanks