Send several messages to a single MQTT output for a matrix display

[foskolo]

Hi,

I'm trying to send some values from sensors in my house (temperatures, door switches...) to a single line matrix display (1x8) which is connected to a Wemos (ESP8266).

For single sensor all works fine.

Now I want to send more different sensor values cyclically through a single MQTT output node.

All the sensor values come in through MQTT input nodes. To send the values to the Wemos I created a MQTT output node with the topic "myValues".

This node should send the sensor values cyclically (Sensor1 - wait some seconds - Sensor2 - wait some seconds - Sensor3 - wait some seconds - Sensor1 again...) to the matrix display (connected to the Wemos that subscribes the topic "myValues").

How could solve the problem?

Thanks!

Karlo

[Christian-Me]

I assume you have a single line matrix display.
You can try an infinite loop with a delay node in between.
As I’m more the JavaScript person I would use a function node storing the data in the nodes context (array preferred because it is easier to iterate). Then send out a value to be displayed together with the index.
When a message including the index comes back increment the index (or reset if >areay.length-1) and send this one.
If a message without the index arrives store/update it and either do nothing or send this one as it is the most recent.
The timing can be adjusted by the delay node.

[dceejay]

If the values are arriving fairly regularly then the easiest way to do this is to use a delay node configured as below

Each incoming message needs to have a different msg.topic set - (one for each sensor). and then follow this with the mqtt out node with the topic set to "myValues".

[foskolo]

Hi Christian,

I will try the "infinite loop", unfortunately I'm non a JavaScript person.

Thank you.

[foskolo]

Hi dceejay,

ist seem to be simple. Some values arrives "fairly regularly" (temperatures), but some not (doors and windows sensors).

I'll try it.

Thank you!

[hotNipi]

Here is basic flow. It is not complete solution and needs many modifications to be error proof. But I hope it makes the overall concept clear.

[{"id":"c8162f53.5016","type":"function","z":"34b4a5e.a6f4b5a","name":"display data cycle","func":"var targets = global.get('displaytargets')\n\nvar current = context.get(\"current\") || 0\ncurrent += 1 \nif(current > targets.length - 1){\n    current = 0\n}\ncontext.set(\"current\",current)\n\nvar sensordata = global.get(targets[current])\n\nmsg.payload = sensordata.name+\":\"+sensordata.value + sensordata.unit\nreturn msg;","outputs":1,"noerr":0,"x":550,"y":820,"wires":[["4103aa1c.c72664"]]},{"id":"62e2d248.f4d99c","type":"function","z":"34b4a5e.a6f4b5a","name":"store globally","func":"var tempsensor = {name:\"temperature\",value:25,unit:\"°C\"}\nvar humiditisensor = {name:\"humidity\",value:56,unit:\"%\"}\nvar doorsensor = {name:\"door\",value:'open',unit:\"\"}\nvar lightsensor = {name:\"light\",value:38,unit:\"lx\"}\n\nglobal.set([\"tempsensor\",\"humiditisensor\",\"doorsensor\",\"lightsensor\"],[tempsensor,humiditisensor,doorsensor,lightsensor])\nglobal.set(\"displaytargets\",[\"tempsensor\",\"humiditisensor\",\"doorsensor\",\"lightsensor\"])","outputs":1,"noerr":0,"x":510,"y":700,"wires":[[]]},{"id":"f3c2a68.f334e58","type":"inject","z":"34b4a5e.a6f4b5a","name":"init objects","topic":"","payload":"","payloadType":"date","repeat":"","crontab":"","once":false,"onceDelay":0.1,"x":320,"y":700,"wires":[["62e2d248.f4d99c"]]},{"id":"403bb2ea.4302dc","type":"inject","z":"34b4a5e.a6f4b5a","name":"2 seconds","topic":"","payload":"","payloadType":"date","repeat":"2","crontab":"","once":false,"onceDelay":0.1,"x":330,"y":820,"wires":[["c8162f53.5016"]]},{"id":"4103aa1c.c72664","type":"debug","z":"34b4a5e.a6f4b5a","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","x":750,"y":820,"wires":[]},{"id":"7c93dd76.a723f4","type":"inject","z":"34b4a5e.a6f4b5a","name":"simulate changes","topic":"","payload":"","payloadType":"date","repeat":"5","crontab":"","once":false,"onceDelay":0.1,"x":310,"y":760,"wires":[["dd609eb6.99d82"]]},{"id":"dd609eb6.99d82","type":"function","z":"34b4a5e.a6f4b5a","name":"store temperature change","func":"var random = 20 + Math.floor(Math.random()*6)\nvar sensor = global.get(\"tempsensor\")\nsensor.value = random\nglobal.set('tempsensor',sensor)\n","outputs":1,"noerr":0,"x":550,"y":760,"wires":[[]]}]