I live in Florida and therefore do not know what cold feels like, but I’m sure many of our readers live in regions that are significantly less balmy. As fall turns to winter, those of you who live in snowy wastelands are probably pulling out the space heaters to put under your desks. Unfortunately, those don’t do much to thaw out your numb fingers. This was the situation Compukidmike found himself in, and why he created this dedicated keyboard heater.
There are, of course, many small desktop space heaters on the market, but they’re almost all ceramic heaters. These provide warmth via convection, meaning they heat up the air and then blow it at you. Compukidmike specifically didn’t want this style of heater, because he doesn’t like the air blowing on his hands. His design is a radiant heater, which provides heat through infrared radiation. This isn’t harmful at all and warms up your skin in the same way that direct sunlight does. Radiant heaters are commonly used in construction, because they work well in open areas unlike space heaters. But radiant heaters are expensive and generally quite large, which is why Compukidmike had to make his own.
The infrared radiation for this project comes from a pair of halogen work lights. These are normally run at something 120V and use 500W, but running them at 24V and 40W forces them to produce heat without much visible light. Power is coming from a huge 65W USB PD (Power Delivery) power supply. The USB PD standard allows for up to 100W. An LED dimmer is used to dial-in the heat output. The halogen work lights were then housed in a 3D-printed enclosure, designed in Autodesk Fusion 360, that can be adjusted to direct the heat. Compukidmike printed this using PLA, but recommends using ABS or PETG to avoid heat deformation. He also says that a beefier power supply would work better in place of the USB power supply, since the halogen bulbs draw a lot of current when they’re warming up. Even so, this is an affordable build if you want a radiant heater to keep your fingers warm this winter.