Stepping down voltages (which PSU?)

My project is currently running on POE using a TP-Link splitter that can output 5,9 or 12V. The RFID keypad is supposed to take 12V but works OK on 9V and the Arduino can handle 9V in too - there's a temperature sensor inside the enclosure to make sure things aren't getting too hot (it's been running for a few weeks now logging temperature readings every 5 minutes and hasn't melted yet :D).

However, I'm going to be changing the Arduino for a Pi clone (Orange Pi PC) for various reasons. This needs 5V/2A input so I can't just bung in 9V like before.

I've read that using a 7805 regulator could cause a lot of heat issues (mainly due to the current) so thinking of using a Buck converter.

However, here's my question...

The PoE supplies 48V to the splitter which seems to be a well made, well known item (rather than some cheap component made by me :D) so should I set the output of the splitter to 9V or 12V? The Buck converter can handle either but I don't want too much heat if I can help it.

This is an Arduino forum and so your question would be more appropriate on a RPi forum.

However... your best option in my opinion would be to switch the splitter to 5V as this is typically at 2A, then use a 5V to 12V set-up DC-DC converter for the RFID keypad which I would assume takes very little power. Then you are running everything at the correct voltages.

bodmer: This is an Arduino forum and so your question would be more appropriate on a RPi forum.

Quite so, but it means registering on yet another forum and I will be interfacing with Arduino. Thanks for your reply, though, hadn't thought of doing it that way! :)