Using multiple Temperature Sensors with 433 MHz

I want to use multiple NodeMCUs as Nodes.
So NodeMCU equipped with a Temperature Sensor (DHT22,DS18B20 ,BME280)
As of now I am sending temperatures using wifi and mqtt but in order to save power I would prefer sending Temp/Hum and Voltage via RF433.
How do I do that? With Wifi I can just send a Text String or publish in different Topics, which is not possible with RF.
So how do I comply and decode the Readout from the sensor into something that the NodeMCU can send via RF and then later can be decoded in openhab. (Something like "Node ID; Temperature; Humidity; Voltage)

I found this sketch:

But it raises more questions then it answers.
Maybe someone can help. I will of course post my working solution here to help others.
Thank you guys so much!!!


If you want multiple temperature sensors i will advise the use of ble with mi flora or mi jia off the shelves sensors. Nevertheless if you want a more diy solution you can indeed go with an arduino + 433mhz.
In my setup I m managing the value coming from the atmega328p with a simple mapping file.

Example :
The atmega read 22°
It add an offset of 55000
The atmega send 55022 with rcswitch library
OMG receive 55022
OMG transfer it to mqtt
Openhab with the help of mosquitto receive 55022
Openhab search on the mapping file the corresponding value
Openhab set 22°

Here is the main principles.