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• This instructions are outdated, some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:
• http://www.adafruit.com/make/mintyboost
• THANKS!!!! - ladyada

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)

Comments

[nkiegrea]

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?

[thanatos370]

If I wanted 2 parallel banks of 2 AA's to increase charger time, would your circuit work still?

[mutantninja6458]

I am from the uk and i am looking to build this kit. i was just wondering whether this is the right boost controller:
http://search.digikey.com/uk/en/products/MAX756CPA%2B/MAX756CPA%2B-ND/1130177

[dragonriot]

Looks about right... I haven't actually looked at the parts list, but all the voltages and stuff on your link are correct

[flocha]

Hi, great project. Does anyone by any chance know the name of this components in Spanish?
Thanks a lot.

[whatchitfoool]

what is he using to hold the pcb? id love to know what type of vice that is

[knexfreak32]

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.

[jlund]

what r the parts caled i would like to know riten now so i can go buy them befor radioshack closes

[09khanyu]

Forget about that. I hadn't checked the user manuel on the original website

[09khanyu]

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.

[legless]

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?

[chadbobb]

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

[ggardner7]

cool

[chndt2008]

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.

[npandey2]

friend can you send me the schematic diagram of your chinese version at [e-mail],i want do do practicle and make it myself,help is appriciated

[mistercrazy]

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 ;E;

[npandey2]

hello friend,did you got any alternative solution to thi ic,me to facing same problem,m from india?your help is appriciated

[ludionis]

I just made a similar item, but I used a 4-AA battery pack with on/off switch from radio shack :)

[npandey2]

friend can you plz mail the schematic diagram of your circuit,i am intrested in do it yourself..id is [e-mail]

[ludionis]

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.

[npandey2]

thankx,did that worked??it delivers huge current??any heating problem??

[rnicholls1]

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?

[koolariz]

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.

[techxpert]

futurlec to the recue

[luftwaffe29]

guys im sorry to barge in like this but i desperately need help in making a cardboard biplane. ive gotta couple o questions. will anyone please be kind enough to answer them

[techxpert]

say yes or ok if you still need it

[239hobbies]

Hey, will this charge an HTC Evo? It does charge on usb, however I'm worried it will pull out to many Mah to fast. I have tried just using a 7805 regulator and have had no luck. I just dont want this thing overheating and destroying a $500 phone.

[techxpert]

don't worry it wont do anything to it it cant fry with this cicuit

[ckrill1]

does this work with the ipod touch forth generation?

[TIDGE27]

Great instructable!
Please may you send me the eage files

[jwoo2023]

ack! digikey is out of the inductor!

[andrewschexneider]

where can you find just a plan usb port like that?

[Kanellos]

Is it compatible with the Zune HD?

[roland985]

It provides the 5v USB power. If the zune can be charged by USB: Yes...

[ipod touch 4g]

How easy is this to build? And what keeps you ipod from overcharging?

[roland985]

Most probably, the iPod's internal regulator

[ipod touch 4g]

One more thing where do you buy these items could you give me the link>?

[bowmaster]

Could you do this with a full sized Altoids tin and use four batteries wired in parallel for more charging time?

[Kanellos]

I have researched this, and four would be too many. Three works some modifications.

http://www.ladyada.net/make/mintyboost/power.html

Scroll about halfway down the page.

[DenKain]

This would be a GREAT project......if you did not have to make the board yourself from what seems to be scratch. I know I am new to all of this but is there an easier way to make this besides what he has shown??