MQTT configuration with ThingSpeak

Hardware WiFi Relay
1

Hi,

I’m new with MQTT. I’m trying to publish WiFi Relay temperature to ThingSpeak but without success. Is it possible? If yes, is it possible to have exemple what i should write in User, Password, Publish Topic and subscribe topic field?

Thanks for help

François

2

I am not familiar with thinkspeak, however it looks like it has an MQTT API:

https://uk.mathworks.com/help/thingspeak/mqtt-api.html

https://uk.mathworks.com/help/thingspeak/use-desktop-mqtt-client-to-publish-to-a-channel.html

You should be able to post directly from the relay via MQTT.

Just enter the thing speak MQTT details into the relay config: WiFi MQTT Control Relay Thermostat - Guide | OpenEnergyMonitor

1 Like
3

Francois, as Glyn suggested, it’s pretty simple to do it.
Just open the “Broadcast Daemon” page of the WiFi Relay and config it like this:

HTTP GET broadcast enabled?: … select it
Site: api.thingspeak.com
Port: 80
URL: /update?key=XXXXXXXXXXXXX&field1=%d&field2=%d&field3=%d&field4=%s&field5=%s&field6=%s (instead of the XXXXXXXXXXXXXXX just put your channel WRITE KEY)
ThingSpeak channel: YYYYYYY (instead of the YYYYYYY put your channel ID)
ThingSpeak RO API key: ZZZZZZZZZZZ (instead of ZZZZZZ put your RO API Key)

After that you have to restart the WiFi relay!

You have to create an account on Thingspeak.com and then creat a channel.
After you create the channel, you’ll find there the Write, RO API keys and the channel ID (API KEYS tab)
On the channel settings tab, just give it a name and select the first 6 fields.

I also selected “Show status” and then saved the settings. You’ll see the values registered (if all went fine) in about 30 seconds.

4

Thanks for your answers,

The broadcast Deamon is not on the menu of the new version of the relay. In the pass, i had the three channels relay and yes, it was easy to broadcast to Thingspeak.

It’s because the broadcast Deamon is not there yet that i try to publish the temperature value via MQTT to Thingspeak.

Follow is the fields of MQTT menu but i don’t know what to write in User, Password and Subscribe topic fields.

Host:mqtt.thingspeak.com
Port: 1883
user:???
Password:???
Subscribe Topic: ???
Publish Topic: channels//publish/fields/field1/

If i try to fill only Host, port and Publish topic field it does’nt work.

5

Yup, it looks like thingspeak has both a HTTP and MQTT API. If possible i would recommend using MQTT as it’s much lighter weight. Either should work, although I have not tested or have experience of either!

6

Maybe this could help you:
https://it.mathworks.com/help/thingspeak/publishtoachannelfieldfeed.html

7

Hi,

I did some tests and i think is not possible to publish to ThingSpeak. ThingSpeak require to have specific format topic for publishing to a field. Follow is the format of the topic.

channels/<channelID>/publish/fields/field<fieldnumber>/<apikey>

The problem is, if a put this topic in the Publish Topic field of the relay, the relay will add /ds18b20/1 and /relay/1 to the formated topic for publishing the temperature and relay state. So, the relay will publish on these two topics ,

channels/<channelID>/publish/fields/field<fieldnumber>/<apikey>/ds18b20/1 (For the temperature)
channels/<channelID>/publish/fields/field<fieldnumber>/<apikey>/relay/1 (For the relay state)

and this, does not respect the formated topic that ThingSpeak expect to receive.

Thank for your help, it was appreciated.

8

Hello, your work was helpful in understanding the issue with thingspeak config?
I would like to know how you finally addressed this issue? Which mqtt broker did you use? It would be helpful if you can elaborate.

Thanks,