In part 1, I outlined my plans to upgrade my USB mug warmer. Today, I have managed to “finish” the project.
After some gluing, and some soldering, and some cursing (burnt fingertips SUCK!), I plugged the warmer into a USB port. No smoke…computer isn’t dead…yay! Looks like it is working!
Sadly, after being plugged in for half an hour..it barely got a few degrees above room temperature. I’m not sure what the issue is..but I’m not happy about it.
So, the plan for now is to get ahold of a multimeter and check my connections. After that, I might up the ante and add a second USB cord to it and make this one a dual-porter.
4 Comments for USB Warmer – Part 2
Jade | July 13, 2009 at 12:26 am
Author comment by andrew | July 13, 2009 at 12:28 am
Pictures are forthcoming. Look for them tomorrow evening or tuesday morning at the latest.
Craig | July 13, 2009 at 9:59 pm
HAHAAH FAIL!
Sorry, I just read your part one and part two.
Here is how resistors get hot:
Since resistors “resist” the flow of electricity.
The closer the wattage values shown are to the resistor’s wattage rating, the hotter the resistor will run.
You used 1 watt resistors!!! HAHA! Thats like adding a heatsink to a mosfet! Lower your resistors amp rating to 1/2 watts
OR lower power consumption and have it 1/4 watt with 25mA. THis way it actually HITS the resistors amp tolerance and it will get very hot but still be ok.
Good luck with your project, and want to make me one for the great advice??? 
I do love coffee.
Author comment by andrew | July 13, 2009 at 10:05 pm
Thanks for the good advice. Apparently, my electrical engineering skils are quite rusty. I’ll take a look and see what I can do
Can we see pictures?