MintyBoost! - Small battery-powered USB charger

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Picture of MintyBoost! - Small battery-powered USB charger
This project details a small & simple, but very powerful USB charger for your mp3 player, camera, cell phone, and any other gadget you can plug into a USB port to charge!

The charger circuitry and 2 AA batteries fit into an Altoids gum tin, and will run your iPod for hours: 2.5x more than you'd get from a 9V USB charger! You can use rechargable batteries too.

Some numbers...
iPod video (tested, using alkaline batteries): 3hrs more video (1 full recharge)
iPod mini (tested w/rechargeables): 25 hours more (1.5 full recharges)
iPod shuffle (unverified): 60 hours more (5 full recharges)
Weight (with 2xAA): 3.5oz

This project is suitable for beginners, some soldering tools are necessary but even if you've never soldered before it should be pretty easy. You can etch a circuitboard and/or breadboard this up, or simply buy the kit from the adafruit webshop.

I've also documented the process of designing this kit, in case other people interested in designing and making kits are interested in learning how to start selling their own kits!

This project was developed under support from EYEBEAM, thanks!

  • NOTICE!!!
  • This instructions are outdated, some
  • minor changes have been made to
  • the kit to make it better. If you're building
  • a purchased kit please read the docs at:
  • THANKS!!!! - ladyada
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Step 1: The Process (Meta documentation)

This next 10 steps detail how I went through the process of coming up with the idea, hardware, design, etc. for this project. It's not 100% correct but it's pretty close. Since this project only took 2 days (on & off) to design/test/release, it's a lot easier to keep track of than something enormous like the x0xb0x.

I also include the schematic/layout files in Eagle format. The prototype one is best for etching at home (its single sided)
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can i use a coiled inductor of 22 mH? Its hard to find the one mentioned in the project!

please reply soon

It will probably be fine. I'm pretty sure the inductor is just an AC choke, but you'll probably experience some efficiency loss due to the higher DC resistance.
chelseam11 month ago

how long does that battery normally last?

JackZ13 months ago

Could I stumbleupon

AnthonyJ24 months ago

A nice effort and I salute your spirit for
developing such a nice product. Well, I even purchased one from Amazon
that can charge up to 6 devices including the latest iPhone 6/6 plus, Galaxy
Note 4, Nexus 6, iPad Air 2 simultaneously in just 2 hours with its unique auto
detection feature. Currently the charger is under 20% discount after applying
this coupon code: 20OFFANU

ajayinstruct4 months ago

There's a must try Ti chip


Where are the parts? No idea which caps i should us if I do make one... It is genius. My 9V battery charger lasts for a few minutes.

The parts are in the .sch

This is very well-done and sexy! I want to make something very similar, and I was thinking it would be cool to use rechargeable batteries AND a small solar panel. The thing could be left on a car dashboard (assuming the sun isn't too bad for the batteries) and it would slowly charge the rechargeable batteries. THEN you could take it along and use it as an emergency power-source for phones. No expensive battery replacement, and no worrying about whether the sun is powerful enough.

Also: I'm not the most perceptive person, so correct me if I'm wrong: but why on earth do they not sell things like this in stores? People whose phones are dying are a pretty damn big demographic (and a desperate one at that!) They should sell these things pre-loaded with batteries at airports, supermarket checkout lanes, etc. What's going on with that?

I found solar-battery chargers on Amazon... check out PowerAdd and Levin SolStar to name a couple. they're about $20-$30 and work fine for me (when I RTM). I don't remember seeing chargers that take AA batteries though.

digipup18 months ago
Mine heats up a lot got any suggestions?
wulfhoul5 years ago
 do any of u know how to add a switch and led to this kit

a switch you would just wire directly onto the red cable coming formt he battery, the LED you would want to place right behindm the switch, probaply you would need a resistor to make sure the LED doesn't get a too high voltage.

indian not max ic max ic equivalent ?

BLR_RAVI10 months ago

just wonderful..a detailed project...

davidjohnson8710 months ago

Great innovation!! But I still prefers the usual power banks because of some reasons that is it is not gonna last for a long time, and these batteries can't be able to charge my i phone even to 80%...

u could also use 2 dc batteries and put them in a watch case or can but the same idea just alittel more work needed to make.

Could I use hot glue instead of foam tape? Also, would this work?


djDarel1 year ago

can i use 4x aa batteries?? thanks..

rregi1 year ago
Hi..I am a student pursuing my third year in engineering..i have taken minty booster as my project..i have successfully implemented this circuit on the breadboard and got the output..but in the PCB m not being able to get the would b really helpful if i get the layout of PCB..thanking you!
joshr1231 year ago
Did the popcorn come with the stuff? if it did what site do you order from that's good customer service!
Schmidty161 year ago
when will u make a solar powered one
Hey Can dis circuit be used for a 4-volt input battery(18650 kind li-ion cell,,2400mAh)????
coz i got six of dem from a laptop battrey.....
It would be great if you would help.......thanks
i don't know for sure, but oh my god! Use proper english! its not that hard to type an extra 3 or 4 keys on your keyboard is it?
scob89 dczupik2 years ago
Only as hard as hitting the shift key to capitalize your sentences. Also, Yes, This can be used with a 18650 Laptop cell. Got a 3AH one hooked up to mine and used a cheap gutted 18650 charger and a 6V solar panel to charge mine. No issues for the past 7-8 months.
Dirk.Steyn2 years ago
I was looking through the instructable and decided that I wanted to add in the low battery LED. I found the circuit diagram in the version 2 schematic showing how to wire it.

My question is regarding R3, the value is not mentioned? Also why is it neccessary if your using two 1.2V cells in series since it gives you 2.4V then while the LED that I want to use has a max forward voltage of 2.4V. This falls within the rating?

Or is the resistor used for when your using 1.5V batteries i.e. 3V? Anyways was just wondering if someone could help me out with the value? Thanks in advance.

Really enjoyed this instructable, still busy with it, but thanks LadyYada for this instructable.
what is he using to hold the pcb? id love to know what type of vice that is
Not certain on the exact name, but i have one very similar i bought at a electronics store called a PCB vise...
flocha3 years ago
Hi, great project. Does anyone by any chance know the name of this components in Spanish?
Thanks a lot.
Products still tend to be sold under their english names... however the part numbers should at least be usable..
thanatos3703 years ago
If I wanted 2 parallel banks of 2 AA's to increase charger time, would your circuit work still?
if you have 2 sets of 2 AA's in series, and these sets in paralell (i.e. so the voltage is still 3V ) then yes it will work, you can also use AA or C or D size batteries..

keigorjai2 years ago
This is one of the best idea I have never seen "IF" I saw this design 5 years ago.

No disrespect at all, but, I had my first 2G iPhone back to 2007 and I already bought this product in the market 5 years ago for my iPhone.

You didn't mention this is the original design, but if there is any product similar to yours. Why pay more for your product? All the big brand such as GP. Their retails price is even lower than yours.

Good luck mate.
If you hadn't noticed, this was published 30th may 2006 - over 6 years ago!

Back when this was designed and available for sale, down here in Australia there wasnt a single commercial charger of this design available anywhere!

I have about 4 of these now, and they still work perfectly (2 x V2 and 2x V3), this design then inspired diy users to modify and improve the design, the company's saw this and developed their own.

Also, personally i would pay for something that i built, i know how it works, and i know wont fail anytime soon. This product is not cheap "Made in China" crap.

Please Check your dates before posting.
- Ralim
TurboSnail2 years ago
Looking at this, the 9v versions are way cheaper to make yourself, and if you're using rechargable 9v's in it is it really that much worse? Especially if you use the high-power ones that you can get now...

Nice project though, I like the presentation v. much!
aerinthaare2 years ago
How much would it cost me to get one of these pre-assembled? I would love to get my hands on one of these, but I solder like an epileptic squirrel at a rave party. I have looked around the internet for a usb charger to run my headphones with, but they never show me the actual power specs for the device output; I do not trust said products.
nodoubtman3 years ago
Mouser is 20$ shipping .. too much!
nkiegrea3 years ago
This is probably one of the coolest things I have ever seen. I downloaded the layout files and I am looking at various PCB Manufacturers... Custom Circuit Boards looks pretty good for these type of prototypes.

Any other suggestions for prototype projects like these?
I am from the uk and i am looking to build this kit. i was just wondering whether this is the right boost controller:
Looks about right... I haven't actually looked at the parts list, but all the voltages and stuff on your link are correct
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