You’ve probably heard of those power bands that are supposed to boost your energy and balance …or something. You know, the ones that magically work really really well in every country except the ones with decent advertising regulations? Yeah, those. Wouldn’t it be cool if you could have a power band that, y’know, actually did something? Like, say, recharge USB devices? Yep, that’s right. It’s time again for “Build Something Weird With Steve”…
Limor Fried’s Adafruit Industries sells a USB charger kit called a Mintyboost. It packs a USB power supply and two AA cells into an Altoids gum tin. It looks like this…
I ordered a kit and soldered it together…
And, sure, I could’ve just put it in a tin and been done with it but, hey, I had all these AA cell holders lying around…
And it turns out that AA cell holders fit nicely onto a 2″ strip of Velcro…
So I wedged the Mintyboost board into a super-custom plastic case (or possibly a dental floss dispenser)…
…mounted it on some Velcro with two AA cell holders on either side, and soldered the leads in place…
Here’s the whole thing assembled, powering my phone. I’m using 8 alkaline cells here but the intent is to use rechargeables. The band is mostly Velcro with some black duct tape covering up the ugly bits. It’s about 18″ long, which allows it to be adjusted from about 9″ to 16″. That seems to be about the right size for an arm band.
I also made two extensions. One’s 28″ long that increases the length to up to 44″ for wearing around the waist or chest. I stuffed pieces of black cardboard into each holder to cover the AA cells, just to see what it’d looks like.
The other extension’s 12″ long, making it suitable for wearing on the leg. Because, who wouldn’t want a USB garter, right?
Now, I know what you’re thinking. Something like this would be really handy on long plane trips. Sure, but unfortunately you’d have to pass through a TSA checkpoint, where the natives might mistake your advanced technology for evil magic. And you don’t want that.
I dunno, TSA regs say nothing about evil magic. Nicely done Steve.
For the next version of the band, you might consider including a kinetic energy converter, a la http://www.npowerpeg.com/ .
Oooh!
That’s damn close to a utility belt that would make the Novella boys insanely jealous.
I’m thinking three power stations for phone, ipod, and something else plus a little wifi hotspot thingy and you could make a mint.
I was looking at this a little while ago, but you just can’t find the altoids gum tins anymore. I really like the idea, since I go past the end of the power lines pretty often in Panama.
Anyway, quick question….doesn’t having 8 (or any more than 3) AA batteries push your voltage over 5 volts? The minty guys say that burns up the guts in a hurry. I am a noob at this, so I probably just missed something. But, how do you keep that voltage under 5 volts that I didn’t see in your step by step? Is it not a real concern?
Thanks!
Max
Yeah, I kinda glossed over that bit. The batteries are in parallel-serial configuration – each holder has 2 AA cells in serial and all the holders are connected in parallel. The voltage ends up at 3V but with potentially 4 times the current. As far as I can tell, parallel-serial configurations using rechargeables is safe. At least mine hasn’t blown up yet. š