MintyBoost! - Small battery-powered USB charger

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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  • This instructions are outdated, some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)

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


djDarel29 days ago

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

rregi6 months 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!
joshr1237 months ago
Did the popcorn come with the stuff? if it did what site do you order from that's good customer service!
Schmidty1610 months 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 dczupik1 year 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.Steyn1 year 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...
flocha2 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..
thanatos3702 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..

keigorjai1 year 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
TurboSnail1 year 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!
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.
nodoubtman2 years ago
Mouser is 20$ shipping .. too much!
nkiegrea2 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
knexfreak322 years ago
i see how this works it uses 2 1.5 volt batteries and then a voltage doubler finely a resistor to bring the voltage from 6.00 v. to 5.00 v. very simple.
jlund2 years ago
what r the parts caled i would like to know riten now so i can go buy them befor radioshack closes
09khanyu2 years ago
Forget about that. I hadn't checked the user manuel on the original website
09khanyu2 years ago
I would like use this to power an arduino with a 3.7V Li-Ion cell. Would I need to make any changes to the components.
legless3 years ago
You say a 9V battery has a high internal resistance and then quote ~2ohms. That is incredibly low resistance - it's almost a dead short. Did you mean it is more like ~2Mohms or something?
batteries are close to an ideal voltage source. An ideal voltage source has a resistance of 0 ohms. 2 ohms is actually pretty high for a battery. Most AA batteries are like 1/4 to 1/2 of an ohm. Shorting it would produce about 3.4 amps
ggardner72 years ago
chndt20083 years ago
Great! China already has the product, price $ 2, I believe they stole your technique. I am Chinese, but I hate the Chinese. . . But such products have a question, that is unstable and may damage the battery. Reduce the battery life, which is found after a lot of people use.
friend can you send me the schematic diagram of your chinese version at,i want do do practicle and make it myself,help is appriciated
mistercrazy3 years ago
I can't find that MAX756 controller in my region(I'm in japan!)
of course i looked through "digi - key" but they didn't have it in stock.
is there any alternative? Please help ;ㅅ;
hello friend,did you got any alternative solution to thi ic,me to facing same problem,m from india?your help is appriciated
ludionis2 years ago
I just made a similar item, but I used a 4-AA battery pack with on/off switch from radio shack :)
friend can you plz mail the schematic diagram of your circuit,i am intrested in do it is
I simply bought a 4-AA battery pack holder, tool an old female usb port and wired the + and - to pins 1 and 4 of the usb port, taped it all up to protect it. Not really a circuit to map, sorry.
thankx,did that worked??it delivers huge current??any heating problem??
rnicholls12 years ago
does the Minty Boost have to be battery powered or could you possibly draw power from another power source such as a solar cell or Lithium polymer battery?
koolariz3 years ago
too expensive :(
9$ boost converter
10$ shipment cost
4$ misc.
already too much, when a 7805 is 1/2$
and if i invest in new rechargable batteries i might as well buy a second battery to carry around. or even a phone..
the project sounds tempting, i'll sleep on it.

nice job, btw.

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