I’ve just started designing something. No progress to speak of, but I’ve got a thermal sensor and a couple other items on the way, while I poke around in CAD this evening. I want the feet to fit “inside” the thing, so it doesn’t try to move around at all. I’ll post stuff as I make progress…
General thoughts: Initially, USB2 powered with a pair of 92mm Noctua 14mm fans. Pretty straight forward. That’s doable in the next week. Got the parts ordered, CAD’ing tomorrow evening. Phase 2 (out a few weeks, probably): Make a new USB 2.0 expansion card that has one of these on the bottom: DIY Magnetic Connector - Right Angle Four Contact Pins : ID 5358 : $6.50 : Adafruit Industries, Unique & fun DIY electronics and kits so it just clicks on and powers up. Maybe add a thermal or sound sensor to detect when the machine is getting hotter or the internal fans are running, and speed up/slow down the cooling pad accordingly (gotta find a use for a few RP2040’s I’ve got laying around!). And RGB LED’s, because RGB makes things cooler, right?
The Noctua’s come with ‘speed limiters’ that should keep me solidly below 500mA until I have the time for the full PWM controlled thing. Once I have that, I’m planning on using a USB3 power negotiating controller to make sure I have sufficient power to drive the fans and any RGB led’s I might have laying around. It’s always an interesting balancing act to see how much power I can draw while staying well within the 900mA (or 500mA: lower would be better). I occasionally make keyboards so I’m unfortunately aware of the power limitations of USB
I didn’t benchmark anything because I spent twenty years working on compilers, so I don’t believe benchmarks (My goal was comfortable lap, not faster device)
I do plan on changing the routing of the cables from the fans to the back so they’re the same length, then shrink tubing them together. Probably won’t do it for a couple weeks, but if you want that and aren’t comfortable in CAD, I’ll update this post when it’s done.