Picture of Make a USB iPhone iPod Charger On The Cheap!

There are many designs for iPhone chargers out there and many are confusing or use parts that are hard to find.  My design uses parts that are easy to find, is tested works with all iPhones and iPods (as of this posting), and just works.  It is a fun and useful project.  I made one a few years ago and put a video on YouTube.  I weekly get many questions about making one.  So here you go and i hope you enjoy it.

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Step 1: Parts List:

Picture of Parts List:
  • 1 - SPST Switch (I used a toggle switch)
  • 1 - LED for "ON" indicator red or green (Radio Shack sells LED's with resistor "350 ohm" you can mount.  That's what I used.)
  • 1 - 350 ohm Resistor
  • 1 - 7805 Voltage Regulator
  • 1 - 22uF Capacitor
  • 1 - 10nF Capacitor (code 103)
  • 2 - 33K Resistors
  • 2 - 22K Resistors (Other values can be used, read step 2)
  • 1 - Female USB Connector (I got mine at a dollar store)
  • 1 - 9v Connector
  • 1 - 9v Battery
  • Electrical Tape
  • Solder
  • Soldering Iron
  • Small piece of perfboard
  • Altoids Tin
  • Dremel Tool with cutting attachment or tin snips to cut the tin
  • Drill for switch and LED hole
  • Hot Glue
  • Paint if you want

You can go here for a good tutorial on soldering. 
For most of the parts you can use techno scrap and recycle old broken electronics or just buy them.
I wanted to use parts that are easy to find and inexpensive so everything can be bought at Radio Shack or if your don't mind on-line shopping I like because it's cheep!  
I hope you enjoy the project.  

Warning: Just a fair warning that there is a small chance that something can go wrong and you can end up frying your really expensive iPod.  Be careful.  

Made a circuit like this, just modified to feed Samsung phones (works on notes, only Samsungs I have around). They need to "see" 1.2V in the data lines of a USB. Check out my charger, its an instructable.

Hi again. I'm also wondering if both voltage dividers are necessary for current reasons or can you just use one?

Hi, took me some time but I finally managed to make it. USB inputs are opposite of what I expected. For some reason it didn't occur to me that that was my problem so I spent forever adding and removing components. As a result my circuit is unbearably messy. I just started learning Eagle PCB and I want to get a board printed for this. Would you have any problem with me getting a manufacturer to print a board for this design? thanks

lukasnebula2 months ago
wait so you are a kid in middle school and you made this?

Yep. Easy if you just put you're mind to it and know how to do it. Made a few other things, just check them out. Go to my page.

Hemanth.GR.152 months ago

Can we use this circuit to charge PlayStation Vita charger?

I have made it... but my iPod wont let me put photos onto my computer :-(

ngibbs21 year ago
How much is CHEAP? what's the total cost of this product?

It depends on if you have the necessary tools yet, or not. You can pick up a hot glue gun for $5 at Home Depot. A really nice Dremel tool will run you around $50-$60. All of the components are pretty cheap, costing me about $10 for them all.

donh4641 year ago
im trying to find all the parts for this project. I cant seem to find the 10nF resistor anywhere. Any help appreciated...

I know its been a year, but for anyone else with the same question, 10nF is equal to .01uF. The capacitors I have found are labeled as .01uF.

kmannarbor3 months ago

how would this design be modified for android devices? Am I'm mistaken in thinking that the two volts on the data line would be unnecessary? If so, would you even need the pcb and all those resistors and capacitors? Wouldn't a voltage regulator be enough?

matt826104 months ago

can I use a LM317 and place correct parts to have an output of 5v and substitute it in?

it works with moto g or samsung's cellphones?

Rodville5 months ago

Would this work with 12V instead of the 9V?

hey rodville yes it will work with 12v but be aware of the amps that the battery gives out. Since this battery only gives 500mAh

My battery pack puts out 3a max

Ok after some research i found out that the input current doesn't matter which means you can use the battery but you will need a heatsink becuase it would dissipate a lot of heat.

jhosborn1 year ago
I am trying to build this charger and the instructions call for a 350 ohm resistor but the closest I can find is 330 will it still work, or will it destroy my brothers phone
ryoung26 jhosborn5 months ago

It will work; that resister limits the current to the LED.

dustinfathead7 months ago
So some of these parts listed don't have their volt listed. The 22ufcap has dif volts. Any help? Just want a more accurate parts list.

ANY voltage for that cap should work.

ryoung265 months ago

My 16 year old son decided to make a charger for his iPhone. He had NO electronics knowledge prior to this project. He taught himself to solder from a different Instructable, and we chose THIS Instructable as it was clear about the need for the 2 volt data signals to get Apple goodies to accept a charge; it had a good materials list; and an apparently clear schematic.

Unfortunately, we found the schematic and the instructions a little hard to follow.

1. Pin 1 of the USB receptacle is not labeled on the schematic. Thus, my son soldered it all together backwards - we didn't discover this till I found a USB pinout FYI, the TOP pin in the schematic is pin 1, which is the LEFT pin looking at a female USB with the "board" at the top, and is the +5v input.

2. The materials list did not specify what type of perfboard to use. We used bare, but in the pictures you clearly used perfboard with plated holes. Shame on us I suppose for not looking at the pictures BEFORE going to Radio Shack, but we sure scratched out heads at the step:"Solder the red (positive) wire from the battery connector to one pin of the switch and from the other pin to the perfboard."

3. About those pictures - they are too blurry to be of much use, frankly.

Overall, this is a GOOD Instructable, but I'm a little disappointed it was Featured; a little refinement and it would be a GREAT Instructable.

ryoung26 ryoung265 months ago

One more thing - the heat sink you clearly used to mount the voltage regulator is NOT listed in the material list. These voltage regulators are pretty sturdy; the current is not very high; and it doesn't last very long when it flows, so I think the component will live until my son loses the charger <grinning>,'s another point where this Instructable is Worthy Of Improvement.

Can u plz explain how to put this together in depth plz
Hey I was really confused reading this????
lharp7687 months ago

did it without the 10nf cap. no issues. love this! thanks for the schematic.

also I used an old Wizard brand 1/2" socket for a heat sink.

KiralyCraft7 months ago

Will this also work for the iPad? What about linking more 9V in parallel to get more amps? Like, same setup, but with 3-4 9V's in parallel?

dbaham made it!8 months ago

First project in a long time, I probably should have spent more time on the board layout, but it all fit.

jknight209 months ago

This is a great instructable but the use of a 9v battery means that you get very little juice out of it. I'm rather a novice at this stuff, what would I need to change to replace the 9v battery with, lets say, 4 AA batteries?

Thanks again for the fun project.

Well, I have been extensively researching to find a 6v to 5v voltage regulator... And apparently, to my surprise, there are none. So, you can do what I'm doing and use 4 AAs and 1 AAA in an altoids tin with a LM1117 voltage regulator. But if you're trying to charge an apple device you'll need to put a variable potentiometer between USB pin 2, and 3, then adjust it until the ipod accepts the charge.

elee07638 months ago

Was I the only one that couldn't get this to work? I built it just like the instructions said, and the light lit up, but the device I wanted to charge (4th gen iPod) didn't charge. This is my first project, could that be why?

elee0763 elee07638 months ago

never mind, I figured out why it didn't work. Radio shack guy gave me a 10 uf capacitor instead of a 10 nf one.

bjones909 months ago

Hi Matt

I really like the article and the design of your charger;
you have a retro/modern thing going that works well. It’s great to see people
still willing to hack stuff together for even modern devices and risk frying
their iPod. I write occasionally for <a href=””>iPad
Repair</a>, I’m assuming this wouldn’t be enough to charge an iPad, what
changes would you need to make to make it suitable for iPad charging?

Best wishes


stevenarango10 months ago

looks very nice. i made one like yours mine gives 5v on the out put

but the battery overheats like mad.... any ideas why have you come across this problem? my usb charger is on my page.... cheers.

The 7805 in this design is capable of 1A so you could draw 1A plus losses from the 9V battery which is not recommended and would explain the hot battery. Make sure that the resistors that you use on the USB data lines limit the charging current to 500mA or less.

anothertaylor10 months ago

I didn't see an answer to the 350 ohm resistor questions. The 350 ohm resistor is a current limiting resistor for the LED. The larger the resistor value the dimmer the LED but less power will be wasted lighting the LED. The opposite is also true, the smaller the resistor the brighter the LED but more power is wasted lighting the LED.

Care must be taken to make sure the forward current through the LED does not exceed the maximum forward current or the LED will not last long. The actual current can be determined from 9V minus forward voltage on the LED (from datasheet) divided by the resistor value.

squall9871 year ago
could you not just short the data pinouts for dedicated charging mode?
hibbly1 year ago
Where did you get the 350 ohm resistor? I'm trying to impress a girl in my Calculus BC class, help me man.
usbmod hibbly1 year ago
u can use any resistors, if u have 2 175 resistors or a 300 ohm and a 50, they add up. so u can splice them together to make 350
just a painting tip, when painting metal like this I find it easier and cheaper (not by much because spray paints cheap) to use somethinglike nail polish where I live a thrift store sells bottles 25cents each so its how I get cheat "paint".
komistar1 year ago
i have made this usb charger and have plugged it into a Sony Ericsson xperia play and it just turned off. i was making this for a ipad mini but wanted to try it on something else just in case. i don't know what is wrong, could it be just that the data wires aren't for this type of phone and only apple devices
divxpa1 year ago
Could someone hel me? I will do this project but i don't know what capacitor to use. It sais we need one of 22uf, but with what voltaje?
I know a very little of electronic, and i don't know what happend if I use a 22uf/25v or 22uf/50v or other voltaje. Please help!
as long as the voltage rating on the capacitor is higher than the voltage you are using, it should be fine :-)
ghasmann1 year ago
what is the voltage of the capacitors?
Devgan1 year ago
I have 5v 800 mah charger. what things are required to make a charger for my iphone.
means what types of resistors and other parts to make iphone charger....can I also get output of 5v and 2v simultaneously from this 5v 800 mah charger
Facsi341 year ago
Thanks for this great instructable. I made it,but finally it only loads my phone (nokia x3-02) my tablet (samsung galaxy tab 2) and many other usb devices, but it doesn't work with my ipod. And it loads the other devices(phone, Tablet,mp4,mp3,another phone) only with one battery (used one Zink-Carbon), i bought a new one (alkaline), it doesn't load any device, and i found at home a battery pack for an rc car (9,6V Ni-Cd) it neither loads any devic. So my questions are: 1. Why doesn't it work with my Ipod? 2 Why doesn't it work with the rc car battery and with the brand new Battery?

Thanks in Advance
yaly1 year ago
This circuit WILL work with ALL iPhone/iPod models (even lightning cable devices) (unless apple does something stupid), if you plan to use it with an iPad use at least 3-4 9v alkaline batteries (Li-ion/Li-po is preferred over any other technologies) in parallel, no the led is just to indicate the battery has enough power to charge a device IOW it is optional you don't need the 350 ohm resistor if you are not adding the led. For EET1982 a power supply does not output current, the load draws the required amount of currents, your S4 charger says 5V-2A, this means it will output 5V and up to 2 amperes can be drawn by a load from it, more than 2 amperes will destroy it or a fuse will protect it if you are lucky. For the capacitors use at least 10V capacitors to be safe, do not join the two middle pins of the usb connector together to the point between the resistors, the configuration in the schematic separates them while giving each 2V. I hope this answers all of your questions, thank you.
eddevine1 year ago
Have an iPhone 5, works grate until it reaches 59% then charger isn't recognized can this be corrected?
ksstms1 year ago
1) You won't need the led and the resistor next to it.
2) 2 AA batteries=3V and that's not enough. You need 5V for the usb port, and even more (>7V) for the voltage regulator
syedj941 year ago
2 questions:
1) If I don't use the led, which parts will I not need?
2) If I would like to use 2 AA batteries instead, what would I need?
i built this, have you found with the circuit during charge large amounts of current are drawn and lost as heat on the 7805 regulator, this circuit drains a normal PP3 9V fast and a lithium ion 9V battery slower but still at a fast rate, this circuit is pulling around 500mA and a 9V battery can not sustain this>
Same question as below. Does this work with the iPhone 5?
mempie1 year ago
I am getting the 5V to the USB but instead of 2V i am getting 4V on the middle leads.

Any Ideas on what went wrong?
i Wired/Soldered it correctly, maybe i got a wrong part by accident?
EET19821 year ago
My wall charger for my Galaxy S4 is 5v and 2A. How many amps does this charger put out? I would think it would take forever to charge the phone. Thank you in advance for anyone that reads and /or comments. Thank you for the cool instructable!!!
martinw221 year ago
What type of wires did you use
Sorry do the dumb question I just started with electronics and thought this would be a cool project to start
mayenliu1 year ago
help! what kind of 22uf should I use? Also is it okay if the green and white data line share one strand of wire.That..they're inbetween the 33k and 22k resistors?
mjdline1 year ago
you mean 10nF capacitor. 10 nano Farad is the same as .01micro farad. Radioshack part number 272-1051.
rafian1 year ago
hello, I just realize one model identical to yours, I have a output voltage 5.06 02.06 data but my iphone does not load. Help me to find the problem, other brand iphone loads.
Sorry, but to clarify: so this circuit would work without the led and 350 ohm? Like if i just unplugged it to save battery?
USBguy1 year ago
Where can i get a bunch of the usb connectors ???
I have looked on line and not found much..........................................
ralicia1 year ago
can you make a video of you making it? It is hard for me to follow the steps you put .
maxchu7651 year ago
will this work on the iphone 3 or 3gs?
does anyone know if this specific design is fully compatible with the new iphone 5? if so please respond, it would be very appreciated
OzzyManson1 year ago
i can't seem to find a 350 ohm resistor. is there some way i can use other resistors to make up for this?
This should help:
thank you!!
OzzyManson2 years ago
could this be made without the LED and Switch? im new at this stuff and would like to keep it simple...
matt.e.jenkins (author)  OzzyManson2 years ago
It could. But I am unsure if the 7805 will draw current when it's not attached with output. I don't think it does. But that why i added the switch and led so I knew the current was cut. So the battery would not drain when not in use.
I'm done this and it all works but the data lines have 1v, not 2. I'm using the resistors you said to use. My iPod says "charging not supported with this accessory". Should I try different resistor values?
tramont2 years ago
Okay so everything is solderded correctly with the right amount of voltage on the data lines. When i check the voltage it says 6.54 but when i plug my usb up to my phone it drops to 2.89 why is this?
matt.e.jenkins (author)  tramont2 years ago
Hmm. It sounds like something is installed wrong. Perhaps the 7805 is in backwards. If your v out is not giving 5v then don't connect you device for it might fry it. You could study some other diagrams online of 7805s and part of my circuit if it would help. Just do some searches. I know it can be frustrating. I can tell you many similar stories. But I hope this helps.
Malicah2 years ago
So I made one of these using 6 "AAA" batteries instead of the 9V. It seems to work fine so far but the 7805 Voltage Regulator gets EXTREMELY hot. Granted I do not currently have a heatsink on it (I will get one soon). I'm wondering if this is normal though, I am Charging a Galaxy S2 phone with it, that from my research pulls 0.7A while charging. So should a small heatsink like the one you have be good enough to fix the problem, or do you think it's something else causing it to get so hot?
Does it make a difference if I put the 350ohm resistor on the + or - side of the LED? Mine is on the + but yours is on the - side. The only thing I can imagine is that it might affect the 22uf capacitor. Hope you can help!
tramont2 years ago
Are the capacitors neccessary? Can you put a better pic of your circuit board?
Sayal Electronics has everything (as usual) including female USBs with the 4 pins. They only have 360ohm resistors though, but that's not a big deal.
Does the regulator need a heat sink or at least be attached to the side of the tin?
matt.e.jenkins (author)  Liam.great982 years ago
The heatsink is not necessary. I pulled the 7805 out of some techno scrap and it had the heatsink on already.
Alright. It gets pretty hot though. Do you think my 360ohm resistor (instead of 350) is affecting that, or anything else?
matt.e.jenkins (author)  Liam.great982 years ago
Are you getting 5v out? If you get a short +to- it gets very hot. Otherwise you should be fine. It could get a little hot though.
tramont2 years ago
I have 4.98v output and 1.98 on the data lines but it won't charge my iPhone 4. Also it won't charge my Sony Xperia ion the charge light will come on but it won't charge. Any help?
matt.e.jenkins (author)  tramont2 years ago
That is strange. It seems like it should work. All I can say is triple check all your connections and give it another try.
Now its showing 4.98 on one data line and 1.96 on the other but its charging my phone correctly though
Please email the answer at
Does it make a difference if I use a 680 ohm LED?
wendal852 years ago
hi i was wondering i have built two of these and the output is 4.9v but the data lines are only 1.96 & 1.97. i was wondering if anyone had any ideas on what could cause this.

i made on not on a board and without the switch or the led the output came out to 5v but the data lines were still 1.97 & 1.96. so i know all the connections are good. the 33k is on the + and the 22k is on the negative i even tried making a third one with different capacitors and got the same outcome.

has anyone had this happen because i would really like to figure out why this is happening, also do you think just trying the 75k and 50k would solve it

some people say they had the problem but the polarity of the usb was reveresed. i tried switching the + and - lead on the 1 and 4 slot but that did not work either
does it matter if i use a 10uF rather than a 10 nF?
Yes, it does matter. 10nf is drastically different than 10uf. I would suggest sticking to the layout and measurements exactly or you might run the risk of destroying whatever item you are trying to charge.
tschweitz2 years ago
How much do all of the components cost?
Selmerman2 years ago
I have 2 voltage regulators, a 7805A-2 and a L7805CV. Which one, if any, should I use?
aali342 years ago
I hate to sound like an idiot... But why do you need the capacitors?
You can do it without the capacitors, but are recommended as they smooth out fluctuations. Since this takes power from a DC source (battery) fluctuations are not that of an issue, but the switch is, everytime you turn the switch on and/or off it makes noise or tiny sparks or whatever that might damage the device you are charging.
Do i have to have a switch and LED or could i leave one or both of those components? if i removed the switch/LED would that change he charger's functions?
Yeah, it wouldn't have the function to tell you whether it is turned on or not :) However, if you're referring to the charging function, it might, or might not, run longer because of the reduced current draw (in this case, by the LED), but it's really doesn't matter because LED's draw very little current at all.
haditronics2 years ago
hi there.
i've a simple question and that's how can i use a lithium-ion battery ( think must series 3 of em ) instead of 9 volt battery . could you help me ?
Forgive me if this is a stupid question but could I not run two 9v batteries one going to a 5v Voltage regulator and another going to a 2v regulator and then attach them to the appropriate pins ??

Size isn't really a concern as im building a charging pack for people live streaming so it would be in a backpack or such with a wire running to the device.

Or, considering that is incredibly inefficient, as i understand it doesnt actually draw any power from d- or d+ it just needs to see 2v so would it accept 1.5v from a triple and would 3v from two triple a's be too much ??

For some reason, to get my charger to charge, first I have to turn it on, switch it to off and then on again quickly. I used a 1A 7805 (without a heat sink). It charges my 5th generation iPod Nano in about an hour.
dorian6352 years ago
Great instructable. works really well. pretty much freaked out when i reversed the spots of the red and black usb wires
Made this circuit and tried charging iPod nano on it, but this seemed to just sit there and stop the circuit from sending charge.....has anyone else had this problem as I'm confused.
hey bro,i hav made dis one but it doesnt charge any of the nokia or lg phones....any idea wats wrong/???the output voltage is then too it doesnt charge...
First of all, you should install a spell checker on your internet browser(sorry, your spelling bugs me)

For your charging problem, you need to supply voltage to the datalines. Phone companies make their phones require special voltages on the two middle wires so that the phone will only charge on a brand name charger. I reccommend you go to the ladyada fourums and ask your question in the Mintyboost section, including your phone models, they will give you the numbers you need
Prelectrons2 years ago
I was able to build it and it seems to work when i connect my phone.but i realised after a few mins of charging that instead of charging my phone,the battery starts to drain!
TurboSnail2 years ago
Nice Project! I'm thinking of making one inside an old mobile phone...
Just one thing though, could you add some photos of a close up of the circuit (perf board) as I would like to see how you've connected the parts in a real-world view rather than just the diagram. Thanks.
Oh wait, no you have. My bad, sorry.
Hi! I'm starting the project soon, but I'm wondering, could I put for than 9 Volts into this circuit?
bowlen1992 years ago
this is one of the best i-pod charger instructables i have seen. its cheap, relatively easy and best of all it works (without burning out my iPod i must add)
thanks Matt
BreeBotJr2 years ago
Do you need to use perfboard or can you just solder it all together using wire?
matt.e.jenkins (author)  BreeBotJr2 years ago
You probably could but it would be difficult.
i did it without.... that was a BIG mess... but it works! :)
Ruslan_nano2 years ago
Hi Bro,
I have a little problem, at Radio Shack they don't sell 350 ohm resistors, but they have 330 ohm with 5% tolerance, can I apply them?
also the LED has 680 ohm resistor not 350 ohm, can I also apply it?

i used the 330 ohm because my electronics store do not sell the 350ohm resistors. an yeah i made one and it works! nice!
matt.e.jenkins (author)  Ruslan_nano2 years ago
The 330 ohm should be fine, but you might want to use a blue or white led since they can take more voltage. If you are talking about the LED with a pre-installed resistor that Radio Shack sells then just go with that. i believe they are good up to 12v.
tlh0824792 years ago
I am not getting as much charge as I would want to with the 9 volt battery, could i use 6 or even 8 double A batterys? I know i couldnt fit it into a Altoids case, but i should be able to get a full charge, without hurting my iphone, right?
matt.e.jenkins (author)  tlh0824792 years ago
i believe that's right. I would use at least 8 AA battery since you need at least 7.5v for the 5v regulator to work. I know this is not the most efficient project but it works with the most common parts compared to other methods.
I think I understand this now. But I have one quick question. I was wondering if the LED, the 22uF cap and the 7805 were all attached to the 9V battery connector, and if the 10nF cap and all four resistors were attached to the 7805 pins? I didn't realize you could solder more than one thing to just a single wire.

BTW, nice build! I really like the case.
matt.e.jenkins (author)  Adambowker982 years ago
and if i understand you right then yes you are right. The LED and 22uf cap are on the battery side of the 7805 and the 10nf cap and resistors are on the USB side.
So there's wire coming from the battery connecter, and then there are several things attached to that one wire. Just making sure ;)
matt.e.jenkins (author)  Adambowker982 years ago
That's right. Like the ground from the battery is the same wire that is attached to the ground in the USB. With other things attached to it along the way.
Sorry to keep bothering you but.... is this wiring diagram correct? I am pretty sure I understand everything now!

Black - Ground;
Red - Positive from 9V;
Lime Green - 5V (from 7805);
Blue & Orange - Data lines to Female USB;
Yellow - Solder points;
matt.e.jenkins (author)  Adambowker982 years ago
looks good :-)
Can you please tell me where you got the 10nF capacitor? I can't find one anywhere!
matt.e.jenkins (author)  Adambowker982 years ago
a 10nF cap is the same as a 0.01uF cap and has the code of "103." If you can't find one at Radio Shack, I would recommend They are cheap and they ship quickly.
brady9112 years ago
Just thought to share that the 10 nF capacitor is at radioshack, sold as a 0.01 uF capacitor.
It works.... After like 3 hours of very hard work! The first time I tried it, my iPod went into a "Turn off and pretend to be be fried for 30 minutes and scare the crap out of my owner" mode... So I was scared to try to fix it. But then I got over my fear, fixed some loose connections, and YAY it works now! Thanks for posting this!
EpicScout3 years ago
hey i was wondering where you could get the capacitors and does it matter if the resistors have carbon or not?
matt.e.jenkins (author)  EpicScout3 years ago
You can get everything at Radio Shack or many places on-line. I don't think it makes a difference if resisters are carbon or not. Thanks and have fun.
thanks dude. i got all my materials from radio shack except a 10nF capacitor which i will be getting today. thanks again!
I can't find the 10nF! Where did you get yours?
hodege2 years ago
will this charge my iPod 4 gen because i made a lot of these usb chargers and most weren't able to charge my iPod. It would be really nice to know before building this.
matt.e.jenkins (author)  hodege2 years ago
It works great on my friends iPod touch 4gen.
dlemp892 years ago
I have everything set up and it was working perfectly when I test ran it but then after I put everything in the altoid tin it came up with the message this device doesnt support charging or whatever it is. What do you think the problem is just a bad connection that I would have to resolder? or is it something else? the 22k resistors i used were 1/4 watt and the 33k were 1/2 watt would that make a difference?
matt.e.jenkins (author)  dlemp892 years ago
sorry to hear that. The different wattage resistors for this project will not matter. you probably have a bad connection in the data lines. test with a voltmeter if you have one and or re-solder all the connections. and hopefully it will work.
Very nice 'ible' but i do have a question, how did you get the usb connector from the dollar store? Also, how do you use a three prong toggle switch?
matt.e.jenkins (author)  yoshiknowsbest2 years ago
The dollar store was selling a USB extension cable with a USB type A male on one end and female on the other. You can just cut off the Female side and use the plug with the wires. you can use a 3 prong toggle switch like a on/off switch by only using one side prong and the middle prong. toggle to one side and the left and middle are connected (on- if you used the left) and toggle to the right and it's off (if you left the right prong bare.) hope that helps.
Might be a dumb question, might not. Just want to know. Don't be mean please. Can I use this to charge an ereader (specifically a Kindle touch). Thank you in advance!
matt.e.jenkins (author)  n00b.cruncher252 years ago
Not a dumb question. I believe it should work. This charger puts out 5v just like a normal PC USB port and I think that is how a Kindle charges so it should work. If you are not charging an iDevice then you don't need the voltage divider (nothing attached to the data lines.) I hope that helps.
Thank you so much :)
bhc182 years ago
My Charger i build has a big problem. It's not charging properly. The charge symbols keep switching from "charging" and "plugged in." I'm not really sure whats the problem and it is not taking charge so far. I followed all your schematics.
matt.e.jenkins (author)  bhc182 years ago
I had a friend with the same problem. If you can, check the voltages to make sure they are 5v 2v 2v and ground. Also make sure you have a full battery. and double check your solder connections. I hope it works out.
Just so you know, I connected both data lines to the same pot divider and it seems to charge just fine! Also, helpful note, capacitors can be connected in parallel to add up the total capacitance (I used 2 x 1uF and 2 x 10uF)
matt.e.jenkins (author)  bo doncha-donch2 years ago
Thank you
landongaga2 years ago
thats a sexy case 4 that charger
matt.e.jenkins (author)  landongaga2 years ago
I thought so :-)
Sorry to be a pain - i am also in desperate need of more info for the 7805 !

Are you using one that supplies 100mA, 500mA or 1mA ???

You see, because i have all three versions and am unsure which one to use !!!

{there is such a thing as too much of a good thing & in my electronic component gathering i went a bit mad and bought a whold range of these voltage regulators!!!}

Many many thanks in advance!
For an ipod you need a minimum of 500mA or higher, but higher the mA or A is better.


You guys don't have to worry about about the mA or A, actually the high the better, because it is like a "supply" of power in a way. The one thing you really have to worry about is voltage it has to stay at 5V or poof!

Anyway an ipad does not charge with a computer because it only supply 500mA from the usb port, that is why you need the ipad charger which puts out 1.5A. And your ipod will work better with more Amps because as I said early it is like the "supply" of power. If you are going to charge an ipad make sure you have 1.5A or higher, cuz the ipad needs more amps. More amps is fine for ipod or ipad, just DO NOT CHANGE THE VOLTAGE!
Absolutely GREAT info bhc18 & Many thanks for the heads-up!

This type of info is always VITAL when making some kind of chearger, ESPECIALLY when USB is concerned & to be used BUT.......

The New ipad's CAN actually be charged with a normal PC - BUT the PC in question MUST have USB_3.0.... Here is a Quote from Wiki's info on it GIVING upto 1.5A @ 5v, and im sure this info is duplicated on a more documented and official website somewhere on the internet !!!

"Battery Charging Specification 1.2[10]: Released in December 2010.
Several changes and increasing limits including allowing 1.5A on charging ports for unconfigured devices, allowing High Speed communication while having a current up to 1.5A and allowing a maximum current of 5A"

From Here:

USB-3.0 Giving upto 1.5A @ 5 volts
Your welcome, and...

It also depends on the mother board some mobo's have different A or mA on their usb ports, but mostly all standard mobo's USB 2.0 port produce 5V at 500mA. And very few computers have USB 3.0.
Yup, your absolutely right, i couldn't agree more!

Hopefully the next 5-10 years will see USB 2.0 phase-out and become as obsolete as USB 1.0 is now, although i do still repair the very occasional pc that has PREHISTORIC USB 1.0 motherboards !!! (How sad !!!)

Also for all those of you out there wanting USB 3.0... One PC i havee in the house i had spent a considerable amout of time, effort & money into but as you said, the mobo only supports USB 2.0, so instead of changing the entire mobo and only if you have a spare PCI-E port (Either x1, x4, x8 OR x16 !!!) a PCI-E USB 3.0 add-in card would be the best idea and also its REALLY CHEAP nowadays, compared to changing the entire mobo setup of the PC in question !!!

Naturally go through and "nit-pick" the specs to make sure it provides the right amps for your needs!

Not only will you be able to have much much much higher data transfer speeds (again, naturally with any tech that allows this high speed to be used this way!) but your USB ports will also be able to supplu more power to devices without the need of using external power plugs/wall-warts/supplies/batteries etc !
shane192 years ago
Hey great charger!

I cant find the 10nf capacitor do i need this or what can subsitute? I also cant find a 350omf resistor but I have a 330 and a 470 what should I do?
science222 years ago
does this work for an iPhone 4s
bhc18 science222 years ago
It will probably work, because the voltage and A or mA from your original apple charger can charge any ipod or any iphone.
jsilvers12 years ago
i was just just wondering if there was any way to add a solar panel to charge the battery so that u don't need to change out the battery every time that it dies
bhc18 jsilvers12 years ago
It would be hard because your asking for a lot more work, like more components like capacitors, and resistors,etc. I don't the schematics for this, but I know you will need to build your own charger for that specific battery and solar panel and probably step up the voltage and amps somehow for the solar panel. I'm not sure, but you may have to figure this out yourself or find a different schematic.
Many many & MAJOR THANKS !!!

Ive been looking for exactly this !

Your right, there are TOO MANY of these homemade chargers out there that DEMAND HARD-TO-FIND components and are not as simply-worded as you have written here, so a LARGE - PORTION of thanks are in order !!!

Two questions:

(i) As i am learning electronics, i have noticed that your resistors used look like 0.5watt resistors, is this a MUST of will 0.25watt resistors do ?

(ii) Please could you tell me the Voltage of the capacitors used so i can begin CONSTRUCTING ASAP --- Because i think i might have everything i need !!!!!

Many thanks in advance & A Most-Grateful Thanks for the extra Push in the right direction !!!
matt.e.jenkins (author)  offtherails20102 years ago
You are very welcome.

Using .25 watt resistors should be fine.

I don't have the charger with me now and I don't remember the cap voltage I used but I bet must anything you have will work. The voltage listed on a cap is the max voltage that it can take before it blows up. So to be safe, since you are using a 9v battery just make sure your caps can take at least 9v if not more.

Honestly, I didn't know there were different types of 7805 regulators. If i did my reasurch right then with this type of charger the iphone will want 500mA so I would probably use the one that supplies 500mA. Though the 1A would likely also work, but I'm not sure.

I hope this helps you. Feel free to leave more questions and I will do my best to answer them if I can.
Hello, matt.e.jenkins

You guys don't have to worry about about the mA or A, actually the high the better, because it is like a "supply" of power in a way. The one thing you really have to worry about is voltage it has to stay at 5V or poof!

Anyway an ipad does not charge with a computer because it only supply 500mA from the usb port, that is why you need the ipad charger which puts out 1.5A. And your ipod will work better with more Amps because as I said early it is like the "supply" of power. If you are going to charge an ipad make sure you have 1.5A or higher, cuz the ipad needs more amps. More amps is fine for ipod or ipad, just DO NOT CHANGE THE VOLTAGE!
DUDE !!!!

I greatly appreciate your extra help !!!

I can now start making this awesome charger thats nice and simple for even a learner of electronics like me !!!!
iamphantom2 years ago
So if im understandin this all right. I need five volts going to the USB and then i can lower the voltage more depending on how much the LED takes. If this is all true then this should work right?

Charger Wiring Diagram.gif
You should actually put the switch on the +9V going towards the regulator because even if you put the swith on the 5v output, electricity will still be running through the regulator and back to the battery via the ground wire.
You should connect the GND on the USB to the GND on the battery and the LED to the output 5v and the GND.
so without a picture:

+ battery To switch

Switch to regulator (pin 1)

Regulator (pin 2) to female usb

female usb to 10 ohm resistor

resistor to LED

LED GND to Battery

If you need me to draw a picture i will

matt.e.jenkins (author)  iamphantom2 years ago
That may work for most things that can charge with USB but for any iDevices that came out in the last few years you really need to make a voltage divider with resisters to provide the data pins with 2volts. I would also put the led on the other side of the regulator. I know my schematic will work, were you trying to change it for any reason? Let me know if you came up with a better method.
im planning on using this for an android phone so i thought that you only need the five volts going into the phone. I ran out of resistors so im trying to use as little as possible. So i just thought 5v could go to the usb and then since my LED is a 3.1-3.5V LED i figured that i could just buy a 10 ohm resistor and use that to adjust the voltage for the LED. Im just not sure how to end the circuit with the wire coming off the LED.
matt.e.jenkins (author)  iamphantom2 years ago
No problem. It would be just the same as schematic in my instructable but you don't need the 33ks and 22ks. The two data lines of the USB can just be left not attached to anything. I'm not sure what you mean by "end the circuit with the wire coming off the LED." Like in the schematic the LED should come after the switch but before the regulator. Let me know if you need more explanation.
cannonata2 years ago
So I've already been working on a battery powered usb charger for a few days now and seen another instructables where the author used different ohm resistors, I believe it was 220ohm and 330ohm, and ladyada's but when I use 2k and 3k, I get the "Charging is not supported with this accessory" screen.
I didn't have many resistors on hand so I connected two 1Kohm in series for the ground and three 1Kohm in series to the Data +/- because supposedly, the total resistance is equal to all the resistor values,in series, added together.
I've notice that this is a relatively new instructable and I believe, according to the comments, that this works on the iPhone 4. I have an iPod Touch 4G so it should work for that, too, but it doesn't.
Any suggestions?
matt.e.jenkins (author)  cannonata2 years ago
2K and 3K is the right ratio. Is the 3K connected to 5V and 2K to Ground? Using the 1K in series should have worked. I know 75K and 50K works (ladyada's) and 33K and 22K works (mine). Maybe give those a try. iPhone4 does work with it. I have tried it. If you have a voltmeter you should check every connection you made to see if they are all reading the right voltages. I hope this helps.

Hi, i'm new to these projects, been looking on instructables for a while though. But it seems you've complicated things by adding extra resistors and lights and stuff. Why have you added them, to avoid short circuiting the ipod or another reason?
matt.e.jenkins (author)  mosstheboss97222 years ago
The switch is just to turn it on and off and the LED is an "on" indicator light. It is not nessary per say but i like LED's and didn't want to drain the barttery when not meaning to. The "extra" resistors are to make a voltage devider to provide the USB data lines with 2V. An newer apple idivice will not charge with out it, but for about anything else that can charge with a USB, the data lines are not needed. You should check out the video in the link in step 5 from Lady Ada.
ojasvi12 years ago
please can you tell me that why did u choose 22k and 33k ohm resistors
i think 6ohm should have been chosen as
and that is definetly not 22k or 33k ohms
matt.e.jenkins (author)  ojasvi12 years ago
You are trying to get 2v to the data lines of the USB. By using resistors with that ratio ie 22K and 33K. With 33K to 5v and 22K to ground, between them will give you 2v. You can also use 50K and 75K. That is what the Minty Boost uses.
Wolfbane2212 years ago
Does this charger work with the iphone 4s?
matt.e.jenkins (author)  Wolfbane2212 years ago
i'll test it and get back to you.
I am new to electronics so I don't know much but I was wondering if when I get the resistors, what wattage should they be.
matt.e.jenkins (author)  newton.95.dan2 years ago
They can be 1/4 watt
gl0rious2 years ago
can i get a price range?
matt.e.jenkins (author)  gl0rious2 years ago
It really depends on what you have and where you buy the items. But it can cost between $7 and $15. I would check out because it's cheap.
sushiami3 years ago
Can you put a video on here of how to put it together?
matt.e.jenkins (author)  sushiami3 years ago
At this time i can't do another video, but if you tell me the problem i can try to help.
I confused on the putting it together part, I can't really see were to put everything.
matt.e.jenkins (author)  sushiami2 years ago
Do you mean the schematic? It didn't turn out so well. There should be a small "i" in the upper corner of the schematic. You can click on that to see a bigger picture of it. If that doesn't help go ahead and write me back with a more detailed question and I'll do my best to help.
I don't really understand the schematic.
matt.e.jenkins (author)  sushiami2 years ago
The left end is the battery and the right end is the female USB. The lines are wires and the parts where they touch and there is a small circle means they are connected. The zigzag lines are the resistors, the parallel lines and the one that has a curve are the caps. The curve one is polarized meaning it has a positive and negative sides. The stripe on the cap is the negative side and has to connect to ground. The triangle is the LED, that also is polarized and the longer wire from it is positive. the 7805 in the schematic is as if the "chair" is facing you, the tab is on the back. Hope this helps.
Thanks man!
Peyton s2 years ago
Would this still work without the 10nf cap and the 350 resistor? I could not find these at my local RadioShack.
matt.e.jenkins (author)  Peyton s2 years ago
You need the 350 ohm resistor for the LED. You could just leave out the LED and forget the 350 ohm resistor. I know radio shack sells LEDs you can mount that come with a built in resister (that is what i used), so you can try that if you want. Otherwise the LED is not necessary, it is just an indicator light. The 10nf is used to smooth out any "noise" in the current before it gets to the devise. i don't have the tools to see it on a graph. you could use a different value as long as it is small as to high a cap may change the voltage enough to mess up your devise. Then again I'm not a pro but you can probably go without it. Hope this helps.
acarlson52 years ago
I made one of these to charge my Motorola Droid 2. Whenever i plug it in the phone turns off. What gives
matt.e.jenkins (author)  acarlson52 years ago
i'm not sure what is up with the droid 2. Is it being charged when it's off? If you have a voltmeter you should check that it is putting out 5v.
Instead of a usb slot, can I use a ipod shuffle charging cable? I want to make a hole in the top, so I can make it like a dock, and there are no external wires to deal with. any suggestions?
I think I understand. That should work.
haizul262 years ago
hey,i need some help. I tried to charge my iphone but the battery percentage decrease instead of increase. may i know why it occurs? thanks :)
matt.e.jenkins (author)  haizul262 years ago
that's strange. Does the iphone have the charging symbol? Have you tested the voltages?
matt.e.jenkins (author)  alindsey33 years ago
Well that's strange. Did you hook up the 7805 correctly? It should have just about exactly 5V out the right pin if you have more than 7V going in the left pin. The middle pin is ground. If the voltage divider is set up correctly it will send 2V to each data line. Check the schematic again, you can click the little "i" in the corner of the picture to download a larger pic if you want, that one is kind of small and hard to read. So from the USB, the red wire is 5V and should have a strait connection to the small cap and the 7805 Vout. The two data lines, usually white and green, should each read 2V. They should both connect between the 2 resisters which go from 5V - 33K - USB data wire - 22K - ground. Then the black USB wire goes to ground, the middle 7805 pin. You should also check all your solder connections. I hope this helps.
matt.e.jenkins (author)  alindsey33 years ago
That's strange, you should be getting some voltage out of it. There may be a loose connection. The other values should work. The higher ohm resister attaches to 5v. See if this makes sense... (disregard all the periods)

________________________________________USB Red Wire 5V
.........USB White Wire 2V........USB Green Wire 2V
________________________________________USB Black Wire GND 0V

If that made sense, is that how yours is hooked up?
matt.e.jenkins (author)  alindsey32 years ago
yup, you are correct. And good catch on me missing the other 33K. And you are right, you place the black (-) lead on the ground wire and move the red (+) lead to test the 5v and two 2v.
moojomoore3 years ago
How would i make this with a 9.5 volt battery??
Betting it would be the same as with just a 9V battery. the regulator takes care of the voltage.
thanatos3703 years ago
What would the circuit variation be for AA batteries instead of 9V? volt booster instead of regulator?
Also, do you have to use a bread- or circuit-board or could you just wire the components together using solder and bits of the right wire?
matt.e.jenkins (author)  thanatos3703 years ago
Using a voltage booster is a very different circuit. the booster is more efficient, but i wanted to use parts that were more readily available. If that is what you want you should check out the Minty Boost at I actually made 2 of them and they work well.

You could directly wire the parts together but it would be tricky and you may get shorts easier.
Thanks, that helps a lot. Would I be able to get a lot of the parts from computers and other electronics?
matt.e.jenkins (author)  thanatos3703 years ago
It depends what you have laying around but yeah you could. In the one I made for the pictures i used techno-scrap for the 7805 and the caps. I'm a bit color blind so i always buy the resistors and keep them labeled. I like to reuse parts from old or broken electronics. It's like treasure hunting. You can save a good amount of money too.
I am searching for a switch online and I can't find one that I think would work. What are the specs for a switch for this circuit?
corylopes3 years ago

I just finished building this project and I must say I had a good time building.
Great job on the toturial.

I recorded some parameter while my charger was a dead cellphone battery. Results are below.

Let me know what you guys think.
Cory. Field Test


This test consists of using the emergency charger to boost a very low level state of charge cellphone battery. The purpose of this test is to measure certain parameters of the charger will it is under a high demand of delivery.

The following parameters will be observed.

Charge cycle time, cellphone battery status (CBS), charger battery voltage (CBV), voltage regulator temperature (VR), and charger battery temperature.


Observation One:

·         Time: 10:31 PM

·         CBS: 1%

·         CBV(idle fresh 9V Duracell battery): 9.6V

·         CBV(delivering charge): 7.4V

·         VR temperature(before charging at room temperature): 22C

·         VR temperature(delivering charge): 65C

·         Charger battery temperature(idle at room temperature): 22C

·         Charger battery temperature(delivering charge): 28C


Observation Two:

·         Time: 10:41PM

·         CBS: 8%

·         CBV(delivering charge): 6.5V

·         VR temperature(delivering charge): 58C

·         Charger battery temperature(delivering charge): 29C

Observation Three:

·         Time: 10:51 PM

·         CBS: 15%

·         CBV(delivering charge): 6.3V

·         VR temperature(delivering charge): 52C

·         Charger battery temperature(delivering charge): 33C

Observation four:

·         Time: 10:58 PM (Charger stopped delivering a charge)

·         CBS: 15%

·         CBV(delivering charge): 6.0V

·         VR temperature(delivering charge): 29C

·         Charger battery temperature(delivering charge): 32C


Observation five: (Charger battery voltage status)

·         Time: 11:06 PM

·         CBV: 8V

matt.e.jenkins (author)  corylopes3 years ago
That's awesome. Thanks for sharing.
oschroedl3 years ago
what are the wattage of the resistors you use?
matt.e.jenkins (author)  oschroedl3 years ago
I don't remember but it's either 1/8 or 1/4. each would work.
So, i'm kind of a tech newbie and this was gonna be my first (real) build. Will this power something like turtle beaches? Or is it only restricted to charging devices?
Yes it should because it plugs into the usb port on the pc/xbox/ps3.. I hope this helped
matt.e.jenkins (author)  giantredfrogs3 years ago
I don't know anything about turtle beaches, but this will charge/power anything that can be connected by USB.
Kante Tech3 years ago
Hey um is it possible to mode this circuit so that it use the same amount of batteries but with out the need of a 7805 and a ic. Basically mod the circuit so that it uses 3v or 5v and does not need a 7805 or ic but just the other half of the circuit.
matt.e.jenkins (author)  Kante Tech3 years ago
The goal here is to have a steady 5v going to the USB. It can be done 2 ways. Start with higher voltage and drop it to 5v (that what i did here with the 7805) or use a lower voltage and boost it to 5v, this way is more efficient (this is what the minty Boost does on So, it can't be modded to much. Maybe I didn't understand the question. Did this help?
Yes it did a little bit. But those the voltage booster from a lower voltage need an ic or can it be just a whole different circuit combine with this orignial one and do you think it would be possible to help me?
matt.e.jenkins (author)  Kante Tech3 years ago
I'm not sure. If you want to work from a lower voltage, like 3v. you should check out the Minty Boost at
momoi3 years ago
good day. i have got a problem when i made my charger it seems like i cant reach a 5v output it only goes up to 4.9 and for the voltage divider only 1.9 and sadly it does not work. can any 1 suggest what to do. i followed the values and the schematic diagram. do i just have a lousy battery? i also tried a 5v adapter as a source still 4.9 and 1.9 can it be the regulator?
momoi momoi3 years ago
woops just got it. reversed the usb polarity. btw this project is good. :D thanks i really enjoyed making it.
matt.e.jenkins (author)  momoi3 years ago
i'm really glad to hear that. Thanks.
Doublekross3 years ago
Very neat, I'm going to have to give it a try.

Also, you misspelled "cheap". 'Cheep' is what birds do. :)
matt.e.jenkins (author)  Doublekross3 years ago
Well, that's embarrassing. Thanks for pointing that out. Let me know how the charger works out for you. Thanks.
ahernando3 years ago
I have a question. Why use a voltage divider instead of using a Voltage Regulator (such as the 7802) which would actually add less noise to your output signal? And another question, could we use this same charger with another phone or there would be a problem with the 2V usb pins? Thx and great job! =)
matt.e.jenkins (author)  ahernando3 years ago
Good questions. I used the voltage divider just because that is what the apple brand used in their charger. I learned that from I haven't used a 7802 before but it may work. As far as other phones go, most others only use the 5v and ground of the usb and don't even hookup the 2 data lines so I don't think you would have a problem. If you know you will not be using this for an apple device, you can leave out the voltage divider and not connect anything to the data lines. Hope that helped Thanks.
Hey i'm interested in making this as my very first project on instructibles.

my main question was that if i could have it that the battery would be on standby (or off) when nothing is connected, but right when you connect the ipod, the ipod battery triggers the other battery, so the charger can charge the ipod without having to turn on the charger....i hope that made sense XD

i want it to be like that so that i can just have a cord coming from my backpack, and lets me plug in my ipod and charge it as i'm using it right whenever i have my bag with me!! it'd be so convenient!
matt.e.jenkins (author)  lvlonstask8er3 years ago
I really am not sure. You would have to loose the LED and the switch. i have thought of this before but i don't know if the 7805 draws power from the battery when nothing is connected to the Vout and ground. If not then it should work but if it does the 7805 would slowly drain the battery. THis is why I added the switch. Well that and I just like toggle switches and LEDs. Sorry that's not much help. Maybe someone else knows for sure. Any takers...
Just attach a switch between the +Vcc of the circuit and the +9V of the battery
It'll disconnect it from the circuit so that it'll consume virtually no power (but the battery will still slowly drain, that's unavoidable)
2wheelD3 years ago
Nice build! I put one together just as your instructions explained and checked for the proper output before connecting it to an iDevice. All outputs were in a reasonable range of your instructions, but the devices would not charge. After testing an Apple charger, I found that the white USB pin is at 2.7 Volts on the Apple charger. I then replaced the 22K resistor in the white line with a 39K resistor and all works well.
nprikkel3 years ago
does anyone have a li-po battery ersion...
OR a eagle pdf already createed that i could download? (9volt battery veresion is fine)
kyadav13 years ago
hey, i want to know how long can it charge the phone....... can it charge a completely discharged phone to a full charge

youtube mp3, youtube to mp3
matt.e.jenkins (author)  kyadav13 years ago
It might not be able to do a complete charge. I use it more for like emergencies. If you want something more powerful, check out the Minty Boost at
hannann3 years ago
cool, ill try this ....but will this be good for my sciencefair ???
matt.e.jenkins (author)  hannann3 years ago
sounds like that's up to your Science Teacher
mgingerich3 years ago
Cool, I'll try it this weekend! But one question: You gave ranges for the capacitor values. Do some values in the ranges work better for this circuit?
matt.e.jenkins (author)  mgingerich3 years ago
The Cap values are 22uF and 10nF. (that's what I used) You may mean the resistors. The trick with apple iphones is they will not charge unless they detect a 2v charge in each data line. There are a few resistor values that can help with this. I used 33K and 22K. The voltage divider will look like this (5v-33K-data line-22K-ground) The data line will be 2v. That is what I used. I know the Minty Boost from Adafruit uses 75K and 50K. I heard that 150K and 100K works too. They will all put out 2v, but as far as what the real difference is, if one set is better or not, i'm not really sure. I hope that's not to confusing.
The formula you need to know is V=IR, in volts Amps and Ohms. The ratio of resistors you mentioned are all the same, which means the between them is the same.

You can think of it this way, the number of volts you have to drop from the regulator output to ground is 5V. You drop a portion of that amount over each resistor, so since the ratio is 3 to 2 you drop 3/(2+3) over the 33K and the remaining 2/(2+3) over the 22K resistor.

If you keep the ratio of resistors the same (3:2) (150:100, 75:50) then the voltage at the middle point will always be 2V.

What does change is how much current is flowing across that point. If the Ipod has current requirements to drive the circuits on the other side there is the possibility that too large values would restrict it too much, but in general the more current flowing.

The more current flowing the more drain on the battery, so using the largest values that work would make the battery last longer.

5V/55K = .09mA
5V/125K = .04mA
5V/250K = .02mA

Hope that helps.

Okay, thanks. I think that answers my question
Hunter2753 years ago
Will this be safe with any USB charged device?
matt.e.jenkins (author)  Hunter2753 years ago
rubanman3 years ago
What a coincidence, I actually have the same LED and switch at home and been looking for a project haha, looks awesome im gonna try it out!
matt.e.jenkins (author)  rubanman3 years ago
Cool, have fun. Let me know how it turns out.
kewlman3 years ago
my usb pins are kinda weirdly colored. i have green, red, and orange. WHICH IS TO WHICH!?
here are all the types of usb pin arrangement:

you want to be looking at the second from top diagram labeled "Standard Type A Pin assignment"
hey thanks for the advice! i got it to work after replacing my usb.
Vijster13 years ago
Here is what I have. The 9volt is connected to the 22uF cap. The red wire is connected to both the cap and the left pin of the regulator. The black pin is connected to both the cap and the middle pin of the regulator. From here, the right pin of the regulator is connected to the 33k resistors+black usb and the middle pin is connected to the 22k resistors+red usb. in-between the first set of 33 and 22, i have the green wire (usb) and in-between the second set, i have the white. Please tell me if you see any mistakes.
matt.e.jenkins (author)  Vijster13 years ago
I see one mistake. You need to switch the red and black wire from the USB. Red is positive and needs to be connected to the 33K resistors. Black is negative and is connected to the 22K resistor. Also make sure the 22uf cap is in the right way. It should have a line on one side. That side is negative and goes to the ground or negative side. The other cap don't matter what way it goes in.
Ok - it shows the battery on screen, and makes the charging noise, yet my iphone's battery indicator (top right) flashes between the bolt and plug icons until it reads: charging with this acc is not supported
What do i do?
matt.e.jenkins (author)  Vijster13 years ago
Like i said before, you told me that you connected the positive USB line to the 22K resister. you have these backwards. that would give you a different voltage in the data line, that's important. It should look like 5v - 33K - data line - 22K - ground. That just may fix your problem.
neodymium3 years ago
I am going to build this and have almost all the parts. i was wondering what voltage the led you used takes? I have a few hundred i collected over the years and have almost every shape, size, color, and power consumption.

Btw, this is perfect for my infrared monocular i was making that uses a gutted out webcam with usb. I couldn't find the right power source and was too lazy to make my own circuit. Thanks!
matt.e.jenkins (author)  neodymium3 years ago
My Led was a red 2v 20ma. I hope it works out well for you. Let me know how it turns out.
thanks. i thought it was a 3.6V (that is the standard) and would have used 3.6V had I not asked. you should specify that 2V in the parts list.

i made it and it turned out great! since i decided not to splice the usb wire and made this gadget, i can just disconnect it and charge something with it.

also, i can tell you the outcome so soon cuz i had all the parts laid out, i just didn't solder them together yet. now i did and it works perfectly. Thanks!
P.S. the led in the pictured looks orange. ik it doesn't make a difference i am just wondering if it is a trick of the camera?
matt.e.jenkins (author)  neodymium3 years ago
yeah, the LED is orange. I bought it at Radio Shack and it came with the resister in it, but for the instructable I said to use a 350 ohm resister and a red or green LED since those are lower voltages, cheaper, and easier to fine. :-) The standard voltage for a standard red or green LED is between 1.7v and 2.5. That is why a resister of 350ohm - 390ohm should be used.
I'm super glad it worked for you. Great job!!!
Vijster13 years ago
is it okay if i use a 330 ohm resistor instead of 350? (it might be 320 - idk)
matt.e.jenkins (author)  Vijster13 years ago
Your 330 ohm resister should be fine. It depends on the LED but the math works out with a 330 ohm resister you will need a LED that had 2.5v forward voltage and 20ma forward current. So if your LED is near that, you should be fine. BTW The color code for 330 ohms is orange orange brown.
NOOOO - i finished and IT DOESN'T WORK!!!!
matt.e.jenkins (author)  Vijster13 years ago
you need to double check everything. If you have a multimeter use it to check all the connections. Make sure you are getting 2v from each data line and 5v to the positive pin (red wire) in the USB and ground to the ground pin (black wire) in the USB. Make sure the 7805 is installed the right way as well as the 22uf cap. Make sure all your solder connections are solid and you don't have any solder bridges. With the probes from the multimeter you can test the 4 pins in the female USB. It's tight but you can do it. That's what I would do. Your .01uf cap must be a different type. I'm not sure how that would change things. Mine is no bigger than a pea.

What dosn't work? What are you charging? Are you getting 5v and 2v data lines? does it just not turn on?
would it make a difference if i skipped both the led and the 330ohm resistor?
my capacitor says 103k - does that make a diff?
103K means 10nF.
Meaning that you should be ok.
matt.e.jenkins (author)  Vijster13 years ago
I think the K is something from the manufacture. It should = 0.01uF. you should be fine.
matt.e.jenkins (author)  Vijster13 years ago
you can leave the LED and 330ohm out. You just would not have a on indicator. That might even save power for the USB.
is it possible that my resistors are on backwards?
matt.e.jenkins (author)  Vijster13 years ago
It doesn't matter what way the resistors go in. They are not polarized.
Right, thanks for everything to begin with. - I am new to electronics, my only projects until now have been involving simple circuits to preform simple tasks. I am trying to charge an iPhone 4 or a kindle. Nothing happens when i hook the device to the cb. My soldering is shady - the wires broke once or twice, and i had to use a lot of flux. I am sure that there are no bridges, and i don't have a multimeter. I don't know what to do - i guess i will just double check everything. (I had lots of 3-way joints)
Found 2 loose connections
also, my .01uF capacitor is the size of a dime - not "little", as you have said in the directions. it this okay?
Thank you, I appreciate your time and help.
Nice build! I was thinking of adding one of these to my car. I haven't done a lot with building electronics and was wondering if anyone could tell me what I would have to change for this to work with a 12V source? Thanks!
matt.e.jenkins (author)  AndyTheTechie3 years ago
Unless you really want to build one, I would check this out
It's a car charger for $2. I bought a few of them and they work great with my iPod Touch 3g.
you would need a different voltage regulator i think to bring it down to 5 volts. i don't know the amperage on this circuit but you may also have to adjust that.
uwezi3 years ago
Everyone building this charger should be made aware of the fact that 45% of the 9V battery's power is converted into useless heat inside the 7805! If you are looking for such a circuit use a switch-mode regulator!
kewlman3 years ago
hey, i cant get it to work. i got the output voltage of 5, but when its connected to the female usb, i dont seem to be able to get the output, neither does my ipod charge. any suggestions?
matt.e.jenkins (author)  kewlman3 years ago
you need to double check everything. If you have a multimeter use it to check all the connections. Make sure you are getting 2v from each data line and 5v to the positive pin (red wire) in the USB and ground to the ground pin (black wire) in the USB. Make sure the 7805 is installed the right way as well as the 22uf cap. Make sure all your solder connections are solid and you don't have any solder bridges. With the probes from the multimeter you can test the 4 pins in the female USB. It's tight but you can do it. That's what I would do.
TigrisLi3 years ago
Can it charge a iPhone 4? Great project!
matt.e.jenkins (author)  TigrisLi3 years ago
Yes it can, just tried it. :-)
is this safe? just trying to be sure
matt.e.jenkins (author)  bethjoven0233 years ago
I believe it is and I use mine. i gave the warning as a just in-case. i would feel horrible if someone did break there devise. you may also want to check out the minty boost from
noglider3 years ago
I've read many of these, but this is the best. Could you please provide a larger jpg of the parts list and diagram? Thanks again.
matt.e.jenkins (author)  noglider3 years ago
Thanks for the kind words. If you click on the "i' in the upper left of the diagram it will bring you to a page you can download a larger image. If you need a bigger one than that then let me know.
Uphiearl3 years ago
Could you use a USB 12v device designed for cars? Take the guts out and use that. Should have the proper circuit.
matt.e.jenkins (author)  Uphiearl3 years ago
I'm not sure how that would work. There may be some resisters and or caps that need changing. It may be worth a try. Could you post how it works out?
Is is possible to as a photovoltaic cell to this charger?
matt.e.jenkins (author)  gmoncayoasan3 years ago
I'm sure it is possible, but there are better ways to do it. I think with my design it may be more trouble than it's worth. I know someone has an instructable on how to solarize the minty boost. I'd check that out.
jander203 years ago
Is it possible to bypass the 10nF capacitor all together ? Or is this a vital component? I haven't been able to locate one locally but have everything else. Thanks in advance :)
matt.e.jenkins (author)  jander203 years ago
My knowledge on caps is quite limited so I have done a little research on it. Since the power is a battery it seems that the output 7805 cap is less important, but it seems that you can use from 0.01uf to 10uf. I would say that lower is better. I got this info from a few sites:;; I hope this helps. I'm not a pro, but I love it as a hobby and try to learn all I can. Let me know how it works out.
Rainh2o3 years ago
Great instructible....and all those that say it shouldnt work or its bad, well, if you have tested it on several devices and it works, then hey it works...I too am an electronics tech and I have seen stuff the engineers say 'That wont work" work fine...real life VS lab conditions and formulas...big difference
Nice looking charger. Well designed. Cheers.
0987HY3 years ago
Ok Good instructable and all and i mean this in the nicest way possible but isn't it bad to put voltage on the datelines
For an iPod/iPhone, there needs to be a specific signal on them or it will not charge
Actually, you should not ever put a constant voltage to the USB data lines. Having studied the USB data protocol, the voltage is constantly fluctuating and pulsing. This can actually damage the iPod/iPhone and screw up the processor inside.

I mean this with the best intentions. Also, a 7805 is too unstable to use as a charger. The voltage protocol for USB says 5V +/- 0.1 volts. The 7805 has too much tolerance percentage, allowing for it to provide voltages from 4.5V to 5.5V. There is a chip, the LM3525 that is specifically designed for providing USB power.

For anyone reading this trying to use 7805 USB chargers STOP NOW!!!
The 2 volts to each data line is really just a sense voltage, not supplying charging current.

Upon connection to a host, USB devices typically signal thier USB speed type to the host by pulling either the D+ or D- data line to 3.3volts anyways. This charging circuit pulls the data lines to 2 volts is the same manner, signaling the IPOD that an 'authorized' charger is attatched. This is absolutely no different than attatching an Apple made IPOD charger.

Lets look at the circuit through the voltage divider. If the IPOD decided that it had to swing the data line to a full zero, or full 5 volts, the max resulting current being sunk or supplied by the IPOD would be either 152 microamps or 272 microamps depending on which divider and which voltage you choose(5volts/22000 or 5volts/33000). Upon connection to a host, USB devices typically signal thier USB speed type to the host by pulling either the D+ or D- data line to 3.3volts through much smaller resistors, on the order of 1.5K to 15K. What this is saying is that it is typical for the D+ and D- lines to experience up to 1.1 milliamps of sink current during typical communication with a host. The charger in this case sinks 272 microamps max , or 4 times less.

This charger is doing exactly what the original Apple charger would do, and the choice of resistors is limiting current to the data lines to very safe levels.
Technically, although correct, it is incorrect at the same time (excuse the oxymoron, I have a lack for a better word, and I mean it with best intentions).

Correct me if I am wrong, you used a multimeter to test the power connected to the data pins? A multimeter USUALLY does not have a fast enough response time to calculate the pulses.

It was my mistake that I did not clarify in my last comment, the POWER lines do not fluctuate, those should be kept constant. However, it is, in fact not very safe to keep the data lines pulled up. I have disassembled and mapped professional Apple chargers and there are multiple APPLE-MADE ICs inside that provide the needing voltages and pulses required for the data pins.

It is not that the voltages are at unsafe levels, but according the standard USB data protocol, the varying voltages between the D+ and D- pins DETERMINES THE DATA BEING SENT. These pins are the data comm. pins, which follow an analog voltage. A constant voltage is bad for the data pins, as it will be trying to send a code that does not exist, and may overall confuse the iPod.

Also, if you are in fact trying to replicate the codes that Apple sends to its products, you are not being legal. Apple is VERY uptight. There are patents in place on everything, INCLUDING THE CODES IT SENDS FROM THE COMPUTER TO AN iPOD.

I will be releasing in Instructable shortly, hopefully within the next few months explaining a proper USB charger circuit.
You are right about the 7805 probably not being the best suited device for providing 5volt power, but this would be the case for actually powering the device while communicating through the USB port. In this case, you would want stable voltage to maintain data integrity.

In the case of the charger and the IPOD charging circuit, the 5volt supply requirements are much more tolerant of voltage swings and wouldn't necessitate more expensive devices.
I was going to say what Kinnishian just said, but I will add that having a constant voltage won't damage anything, proviging it's within spec, and it seems to be. So no problem.

I can't pretend to know exactly what you're saying, but you're flat wrong right off the bat about USB voltage. USB voltages fluctuate more than that, more like 4.75-5.25, and most electronics can tolerate a variance greater than that. It would be asking a lot of electronics to require a minimum voltage protocol to only allow 2% tolerance.
I see......
Well I guess you learn something new everyday/
kalmahot3 years ago
muy bueno, gracias y felicidades =)...
I made something similar to this (only i used a 5v wall plugin type power supply) and i found that only 2.0V on one data pin and 2.8V on the other data pin caused my iPhone 4 to charge. So i had two voltage dividers (one for 2.0v and 2.8v). What iOS device were you charging? it would be nice to know exactly what voltages we should use.
matt.e.jenkins (author)  bobrigewitch3 years ago
From what i read from Lady Ada, having 2.0v and 2.8v tells the iDevice to draw about 1amp which is to much for the battery. Making it 2.0v and 2.0v tells the iDevice to draw half an amp which is about right for the battery. So if you are using a wall plug then 2.8v would be good, but both 2v is better for batteries. Hope that helps.
mir0k3 years ago
excellent work
meccael3 years ago
Nice work! Thanks for sharing.
this definitely looks simpler than the mintyboost.
I find altoid anythings to be interesting, but this one looks much neater than most of the others I've seen. awesome 'ible!
80$man3 years ago
Very cool idea! Great Instructable! 5 out of 5! I'm gonna build one for my HTC!

I'm am going to change a few things:
1) Use the storage tin as the heat sink for the voltage regulator
2) Squeeze a larger/more batteries into an alternate tin (no Altoids in RSA)
3) Add two external ports to charge with three way switch: on/off/charge
I'd suggest building a MintyBoost instead... sorry for the shameless plug, this is an excellent instructable, but for HTC Android phones, a Minty with 2 AA rechargeable batteries can give it a 66% charge on a standard 1400mAh battery. Plus, AA batteries cost a lot less than 9V. If you can find the narrow altoids tins, they fit 2 batteries perfectly... the larger ones can fit 4 batteries, but then you need to adjust your wiring and add resistors. You can get the whole kit for like $15.00 and all you need to supply is the Altoids.

For iDevices, this one looks awesome, and if I didn't already have 2 of the other ones I just mentioned, I might be inclined to build it. =) great job.
Thanks, will do the Minty with 4x 2500 mAh (rechargables) for my HTC, but I think for a camera the 9v option would be better... Building both then...
Also, make sure you get their modded instructions for the 4 batteries... wow... 4x2500mAh would charge a car battery... lol (just kidding) but it will damn sure charge your phone a few times over.
matt.e.jenkins (author)  80$man3 years ago
Awesome, that sounds great.
Well done in the zazenergy's challenge: Altoid Tins! Congrads!
LaserDave3 years ago
@ALL -
The two data lines have to be held at 2.5v for the iPod/iPhone to charge, it will just sit and ignore the charger input voltage otherwise. As you can see, the two resistors connected across the +5v and ground create a "voltage divider" that splits the voltage in half to provide the required 2.5v. Each pair of resistors that connect to each data line are usually the same value and should be between 10k - 100k. You can also tie both data lines together and use only one pair of resistors to provide the 2.5v if you like, but you might want to stick to 10k resistors for the slightly higher current.

Since the data lines normally receive a voltage that alternates between approx. 0.5v and 4.5v, of course it is safe to send in 2.5v without damage. In fact, this is how almost all wall or "cigarette jack" chargers handle it. Besides, at a resistance value of 10k the current produced is only 0.05mA.

The comment about the 7805 not being accurate enough is incorrect. If your regulator is giving you such wild fluctuations, you haven't sufficiently bypassed it with capacitance. By placing a 0.1uf ceramic capacitor across pin 1 and 2, then another across pin 2 and 3, that will take care of oscillations and fast surges - then add another 1uf across pins 1 and 2 to add extra damping. BUT, you still need something large (100uf) at the battery wires where they enter the circuit to take care of the impedance. And finally, you need another 100uf or larger on the output of the regulator to take care of surges demanded by the load. These 5 capacitors will guarantee a voltage that will range from 4.99v to 5.01v which is more than acceptable.

By the way - I'm an electronics engineer doing power control for the last 24 years, mainly working on lasers and beam steering which needs VERY good power quality.

camiller3 years ago
My only thought - I'd try to find a lower profile slider switch. Less chance of it getting accidentally switched on in your backpack/pocket/etc.
Robot Lover3 years ago
I love the look of the case! Most people that attempt electronic builds inside of an altoids tin usually don't have that good of holes for switches etc. Good Ible 5*!
matt.e.jenkins (author)  Robot Lover3 years ago
Thank you
ramascour3 years ago
nice work