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?

Tested this today: it works fine!

In the meanwhile,I also found this:
https://forum.mysensors.org/topic/2725/sensebender-micro/30

My platformio.ini file:

[platformio]
src_dir = WindowOpenSensor

[env:sensebender-micro]
platform = atmelavr
board = pro8MHzatmega328
framework = arduino
monitor_speed = 19200
lib_deps =
  548  ; MySensors
src_build_flags = 
  -DMY_RF24_CHANNEL=100

The comments at the top in the first two sketches mention the pin numbers of the CE and CS pins reversed, the code itself is correct.
The third sketch lacks these definitions, so it won't work.

Can I use this board to use the Sensebender micro with Platformio?
https://docs.platformio.org/en/latest/boards/atmelavr/pro8MHzatmega328.html
This is the 3.3V 8MHz version of the Arduino Pro Mini, which seems correct to me.

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"?

@thierryd Nice idea.

Two remarks:

You write in the cpp file:

if (BatteryType == 2) {
/* LiPo voltage ...

You probably mean here "AA voltage"

The AA batteries you talk about are Alkaline (not rechargeable)?
The values are different for NiMH rechargeable (which I always use).

@gohan yes it confuses me too. I have a similar situation where my node with 2 sensors is recognized by Domoticz as 3 devices like: Temp, Hum, Temp+Hum.

Apparently Domoticz is able to recognize that the different sensors belong together, but sometimes, there is a disturbance or bad reception in one sensor message, and then Domoticz creates a new device for it.

That would not be such a problem, except that you do not know which device to show on the Domoticz dashboard. Personally, I choose the combined one, ignore the others, and live with it.

I do not know if this is a bug for the Domoticz people, maybe they can resolve this?

Regards, Michiel

Oh, I just remembered, a 4051 contains a 1-of-8 multiplexer, and is cheap.
Look also at the 4052 which contains two 1-of-4 multiplexers.
Search on ebay for: 4051 DIP

I would use a 4067 IC for the analog voltage, and probably a second 4067 to switch the power. Then you will only need one analog line of the Arduino, and a few digital lines.
See http://assets.nexperia.com/documents/data-sheet/HEF4067B.pdf
The 4067 is one of the 4000 series CMOS chips, which work with 3V to 15V power supply. It contains a 1-of-16 multiplexer of analog switches. For a smaller number of analog switches, you could use 4016 or 4066.

Please check if you are not having resets in your gateway due to this:

https://forum.mysensors.org/topic/4462/gatewayw5100-unable-to-get-working-w-v2-0-0

https://forum.mysensors.org/topic/4680/mysensors-2-0-ethernet-gateway-atmega-w5100-restart-all-time/6

Regards,
Michiel

@meddie : Sure, I can:

The following is an extract from the code shown at https://www.mysensors.org/view/1/Sensebender-Micro, from the "loop()" function:

#ifndef MY_OTA_FIRMWARE_FEATURE
  if ((measureCount == 5) && highfreq) 
  {
    clock_prescale_set(clock_div_8); // Switch to 1Mhz for the reminder of the sketch, save power.
    highfreq = false;
  } 
#endif

If you remove these lines, it will stay on 8MHz.
(I did not test this but I am quite sure)