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iPod-Compatible USB Battery


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I was able to make a prototype design that will charge the iPod by copying the pinouts of the wall wart adapter. I need to do more testing, and I'll release the schematic and information soon.


I have released the information about the iPod charging design to the Hak5 Dev forums. If you are interested, check it out here, but if you aren't a dev, you can't see it.. :( :: http://hak5.org/forums/viewtopic.php?t=2380


I'm working on a little hack of my own regarding making an iPod-Compatible USB Battery. The purpose of the hack is to have a power source for the iPod through a USB port in a battery pack, and to be able to add some more hours onto the iPod's battery life. This is also a good idea if all you have available are disposable batteries, and a dead iPod.

So I found an adjustable power regulator, a power source, and some resistors to create a 5v out potential. I salvaged a USB port from a PS/2 to USB adapter lying around. I connected everything and made it all good, but when I connect the iPod, it doesn't work!

I have everything together so far, except I found that the USB port only 'wakes up' the iPod. I checked the iPod's detection of power sources patent information, and it turns out the iPod detects voltage potentials on the data lines to determine what kind of device it is connecting into, of which USB Battery is a choice.

I need to know what the voltages are to apply to the USB data lines so that my iPod will detect the power and try to use it. Can anyone help with this hack?

NOTE :: The idea from this hack came from hack-a-day's ipod altoids battery pack v2, except this battery pack hasn't been made to work via USB for the iPod. Everyone wants to give up on it, but I know there's a way to do this.

Any help would be appreciated!!

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you need to add a bit of wire from the hot side pin on the USB connector to the metal case of the USB connector to make it work for ipod mini but other then that it works just fine for ipods don't know where u got your information?

yeah it's simple as hell I have 6 of the little devils setting next to me right now, all you need is a

box like say a alitods gum tin or radio shack project box

9v battery

9vbattery leads

5v regulator

Female USB A connector

A bit of wire

And a switch

The 5v regulator has three connections a in for the 9v from the battery a ground for the ground of the battery and the ground of the Female USB, and a output which is where you get you 5v which is what usb provides for power.

Knowing that USB uses 5v all you need to do is figure out with of the 4 pins in the usb connector is the positive and which is the ground and your good to go.

I think hack a day and a few other sites have directions with pictures, but it’s pretty simple and just takes a tiny bit of though to figure out.

Also this thing will charge any thing that can charge with a USB cable not just your Ipod, that said people who are willing to pay for the over priced Ipod are willing to pay good money to have you make them this little toy! Enough money that I could afford a some more laptop ram, something to think about.

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Sorry if I misunderstand, your typing uses next to no punctuation.

Currently I have Pin 1 connected to the 5v+ on the output connector, and the pin4 negative to the negative rail. As far as I know, USB spec calls for the outside case of a USB connector to be a positive ground; are you telling me to connect this to 5v?

I know the other articles are out there, and sure they may work for the iPod mini, but this is the full iPod, and if you carefully read the progression of comments, you'll see that no one has been able to successfully do this in a way compatible with the larger iPods; in fact, most people think its impossible to do (even though the iPod documents specify USB as a charging source).

It is also worthwhile to note that many people have tried charging directly through the USB connector with no power regulation. This will burn out any iPod. The iPod expects 5v potential, and will NOT regulate USB in. They figure the designer is smart enough to know the internal power potential in the device is 5v, and USB is a direct input to the power rails of the device.

I currently have the power regulator outputting 5v and everything should be dandy, heck, even some different devices will charge from it, but because of the unit identification part of the power detection spec, the data ports need to have some kind of potential on them. I don't know what it is, however, because the iPod patent doesn't go into that kind of specific detail.


Edit ::

After a little more research, it turns out voltages for the DP and DM lines are identified by "an available power indicator 204" (204 is an identification number). Further schematics show it is detected with a resistor arrangement biasing each pin to the next. This is only in the iPod power input however.. this doesn't answer the question of how much voltage is required on DP and DM.

[0053] FIG. 4B illustrates a table 450 that provides a representative correlation of high voltage level to available power. The table 450 is suitable for use when the power source is a battery pack. The table 450 can indicate characteristics of the battery pack, which indirectly provide an indication of available power. As shown in the table 450 illustrated in FIG. 4B, a high voltage level H.sub.1 can indicate that the corresponding battery pack has one AA battery. A high voltage level H.sub.2 can indicate that the corresponding battery pack has two AA batteries. A high voltage level H.sub.3 can indicate that the corresponding battery pack has two AAA batteries. Additionally, in general, the n.sup.th high voltage level (H.sub.n) can indicate that the corresponding battery pack has three AAA batteries. Although the high voltage levels H.sub.1, H.sub.2, H.sub.3, . . . , H.sub.n can vary depending upon implementation, these voltage levels are all "High" level.

In english, this means that the voltage on DP and DM somehow controls the amount of watts available on my USB battery pack, depending exclusively on how much power is available on the pack, and how much voltage is present on DP and DM.

[0054] In other embodiments, the sign (positive or negative) of the voltage difference (e.g., V.sub.DPM=V.sub.DP-V.sub.DM) can be used to distinguish different power sources. For example, if the voltage difference is positive, the power source can be deemed a power adapter. Alternatively, if the voltage difference is negative, the power source can be deemed a battery pack. The magnitude of the voltage difference can then be used as noted above to directly or indirectly signify level of power availability.

This at least answers a little of a question. The voltage difference between DP and DM must be negative to be identified as a battery pack, however the magnitude of the power detected is reliant on the voltage levels of the two data lines.


Links of interest ::

Section [0067] ::

Detection of a USB power source on iPod - United States Patent

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take a multimeter and see how many volts your USB port on your computer is giving? i am looking at an old white ipod right now chargeing from a 9v in an altoids can. next time you wanna nit pick about fucking punctuation remember i'm not the one who can't build a simple circuit!

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Q: What kind of battery does the iPod use?

A: The iPod uses a lithium ion battery. The first and second generation ("non-dockable") iPods use a Sony UP325385 A4H 3.7V 1230mAh lithium ion polymer battery. The third generation ("dockable") iPods use a 3.7V 630mAh lithium ion battery. The first generation iPod mini uses a Sanyo EC003 3.7V 400mAh lithium ion battery.

See this table for more information on battery capacities on various iPod models.

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Taking a multimeter to the output of the dataports on a wallwart or something is a shoddy way to do it. As you know, a positive difference means its a wall wart, and a negative means its a battery pack. The magnitude means how many power levels are available. I suppose this could be done, though.

Hey look, I don't mean to induce swearing and everything, and this certainly isn't a simple circuit if no one so far has been able to get the higher generation iPods to charge correctly on a USB architecture.

Any constructive criticism or ideas for this hack are more than welcome! :D

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take a multimeter and see how many volts your USB port on your computer is giving? i am looking at an old white ipod right now chargeing from a 9v in an altoids can. next time you wanna nit pick about fucking punctuation remember i'm not the one who can't build a simple circuit!

calm down love

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Im jsut gonna say, this was on hackaday way back in liek august (dont have a link) its wuit simpley a 7805 with a 9volt to a male usb (Or a zenith diode)

YOur USB port is 5v at 500ma. Al u need is 5 volts to the ipod, if u know anythign abotu electonics, ud know that at 5v ud get the amsp u need automaticly as long as u can provide them. Although a 5v regulator is the best in terms of clean power, it is horibble in terms of battery life. A 5v regulater will literly take the 9v and take the 4 volts of extra potential nad turn leik 90% of it into heat, Ull still run the same wattages formt he battery, just not the sameinto the ipod. A zenith diode, will "go both ways" aat a sertian voltage. THe trick is, to have 2 resistors in serias. ! beign 4/9 and the other 5/9 in compareison to one another. THe law of electonis says, that the 4.9 one will get 4 volts, and hte 5/9 oen will get 5 volts. You could do it that wauy, just parreler the 5/9 one with ur ipod. A zenith diode would be an ok way of doing it. THe ipod has an internal voltage regulator, so if its aroudn 5volts, it shoudl work. Rember kids, if the battery gets hot, IMIDIATLY disconec tthe power and u should be fine (thoguh ull severly lower the battery life).

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Again, read the comments on the hack a day post and you'll see the problem.

The HackADay Instructions are invalid for the regular iPod

I've tried it, it wont charge the iPod, it just wakes it up. The iPod needs to detect voltage on the data lines in order to get power, except for the iPod shuffle, which is the only one that will work on this charger.

Also, theres plenty of other battery packs out there that are Firewire. This needs to be a USB solution.

That said, other than people stating the presence of articles on this stuff, which I've already researched, what voltages need to be on the USB data lines in order to tell the iPod "I have x watts available, and I'm a battery pack."

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I've resolved I'm going to check the potential voltages on all lines between an ipod and a wall charger and see what's going on... I've spliced a crap USB cable onto my breadboard, with a female USB plug on the other side of it, and exposed jumpers with which to put the probes on. I'll test it today and see what I can find.

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  • 6 months later...

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