I gave some remarks on the code, which were processed.
If there is a feeling that adding the HeatIndex complicates the example, maybe this example should be a separate file, named "DhtHeatIndexSensor"?

OK, I understand.
My confusion was caused by the second sentence at https://www.mysensors.org/hardware/micro : "... it operates at 1Mhz ..."
That's a mistake then?

Under "Signing CLA", the link to clahub.com is since long dead.
Maybe you can follow this example: https://github.com/chocolatey/choco/issues/2036
and replace with https://cla-assistant.io/ ?

I also have a few of such Arduino Unos with a 3.3V selection switch from the shop "Open Smart" on Aliexpress.
See picture at: https://michiel.vanderwulp.be/domotica/Modules/ArduinoUno/#open-smart-3-3v-5v-switchable-uno-specification-1
They work fine, also on 3.3V.

But indeed, running it at 16MHz on 3.3V is out of spec...

I even managed to solder a nRF24L01+ to the board so everything works on 3.3Volt, and this node works fine.
This took a lot of scratching copper from the board...

If you have two nodes with the same ID, the MySensors system can not work good. You solve this by clearing the EEPROM, see https://www.mysensors.org/build/debug at least for one of the nodes. After this, the gateway will send a new node id to the node.

Also the MQTT gateway is supported according https://www.domoticz.com/wiki/MySensors
It even supports new node ID generation.

I even managed to solder a nRF24L01+ to the board so everything works on 3.3Volt, and this node works fine.
This took a lot of scratching copper from the board...

I also have a few of such Arduino Unos with a 3.3V selection switch from the shop "Open Smart" on Aliexpress.
See picture at: https://michiel.vanderwulp.be/domotica/Modules/ArduinoUno/#open-smart-3-3v-5v-switchable-uno-specification-1
They work fine, also on 3.3V.

But indeed, running it at 16MHz on 3.3V is out of spec...

At "https://www.mysensors.org/download/contributing#coding-guidelines-core-library", under "Signing CLA", the link to clahub.com is since long dead.
Maybe you can follow this example: https://github.com/chocolatey/choco/issues/2036
and replace with https://cla-assistant.io/ ?

@canyouhearmenow : in stead of the internal pull-up resistor for the reed contact, I used an external one of 3.3MOhm. Is that a good idea?

I have two Dooya motors DT82TN with a DC2760 remote control, which is 433MHz.
After a lot of investigations and experiments, I got them working with Domoticz (running on a Raspberry Pi), using the following:

• A Broadlink RM2 (RM Pro+) which supports 433MHz. The official Broadlink app is cloudbased and can "learn" the codes to operate the Dooya, but I abandoned this since I want integration with my domotica system, not just another app on my phone.

• The software at https://github.com/mjg59/python-broadlink works with Broadlink devices, but does not integrate well with the RM2. So, I only use this for my thermostat, not for the Dooya curtains.

• The "official" Domoticz plugin described at https://www.domoticz.com/wiki/Plugins/BroadlinkRM2.html is an old version, that is not supported any more - as stated at the top of the page.

• The "zak45" Domoticz plugin that works is described at https://www.domoticz.com/forum/viewtopic.php?f=65&t=33223#p251517 to be downloaded at zak45's Nextcloud drive: https://synnas.publicvm.com:4430/s/Czn9r8G8QwrZ7ji

• This latter plugin is not easy to use, and has special added webpages to Domoticz. It is however able to use the RM2 to "learn" IR and RF codes from the UI of Domoticz. However, there is a bug due to which the learning of RF codes does not work from the UI.

• I was able to use the command line on the RaspberryPi with the above given plugins to detect Broadlink devices. And this way, I could also learn the 4 RF codes I needed for my 2 curtains: open/close for each. This gave me the code as some numbers, which I stored in a text file.

• Since the IR learning works, I used this to learn 4 commands, and then looked where these codes were stored on the Raspberry, and replaced them with the RF codes. This was easy.

• Just a tip: I used Dolphin with fish://raspberrypi/ to browse and edit the files on the Raspberry from my desktop PC.

Under "Signing CLA", the link to clahub.com is since long dead.
Maybe you can follow this example: https://github.com/chocolatey/choco/issues/2036
and replace with https://cla-assistant.io/ ?

In Belgium, the aliexpress price now includes taxes, and we do not pay for import, just like @Tmaster described for Portugal. So, it is still cheap...

@Dbagioni said in Safe AC dimmer with code:

zcPin

Which pin do you use? The comments say something else (twice) than the code.
Which CPU do you use?
For many Arduinos, you can only use pin 2 and 3.