I’m looking for a safe way to heat and maintain a pad (probably aluminium covered in some sort of skin plastic or wood), at 110-120F/ 43C-49C about. I know I can use resistors, Diodes (Specifically LEDs in a grid generate enough heat for what I need), peltier plates, PTCs, resistance wire, fire, etc. But what is the most efficient and safe way to maintain a constant temperature across a plate. Like a heating pad but rigid and can maintain a temperature for hours without burning out or over heating.
Essentially my cat keeps sleeping on my laptop and phone and causing them to overheat. I can keep her off of them with better storage, but I’m a softy and want to give her a nice warm place to cuddle up.
I’ve got a bunch of micro-controllers in the Arduino family that I’m comfortable with and I will use a relay to control whatever the heating element ends up being, so I’m just looking for help on the heating side of it (I don’t mean to be rude, but I’ve seen discussions on other more specific forums get really side tracked about controlling “x physical thing”).
I want to use a few heating elements (so resistors would be fine if they’re an efficient way of delivering the heat, but I’m guessing there’s better), across the pad to maintain even heat. If it comes to safety vs efficiency (or long term cost in this scenario), lean towards safety. And if it’s choice between longterm cost and a significant (3x-4x times cost) initial cost, please just say it’s a crap shoot.
Thanks in advance for helping my very very tired self.