Make your own iPod/iPhone/GPS/etc… battery-pack and recharger! This project includes all the electronic parts necessary to build your own MintyBoost: a small & simple (but very powerful) USB charger for your iPod (or other mp3 player), camera, cell phone, and any other gadget you can plug into a USB port to charge. If you have a Nintendo DS/GBA or a PSP you can buy charger cables from us, too.
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 rechargeable batteries too.
New In Version 3: Provides 500mA @ 5V, tested and designed to work with all the latest iGadgets including the latest iPhones and iPods!, improved efficiency for high-drain devices, works much better with LiPoly battery mods.
Kit comes unassembled and is suitable for beginners. Some soldering tools are necessary but even if you’ve never soldered before it should be pretty easy.
Read more about the project on the Minty Boost webpage.
Tested works with: iPods, iTouches and iPhones (including the latest 4G), PSP, DS..Please see a full listing at Minty Boost compatibility webpage to see if your device is tested to work before purchasing. Batteries and tin not included. If you live in an area that doesn’t have Altoids gum, you can buy a tin from us. You can also of course make your own case!
*Please make sure to read the project pages before purchase and assembly, some phones may require modifications to the kit to charge properly
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scharf, some people have older ipods where the battery has worn out and died – but they dont want to spend $$$ to send it off and replace the battery inside 🙂 this keeps old devices rockin’
Hey There! Glad to see a v3 of this. I actually have two v2 minty boosts. Can I just rework the resistors to force 500ma charging? I actually don’t mind paying for a couple of new ones, just would like to salvage the old ones too if possible.
Thanks for all your hard work!
Also I have done some experimenting with iPad charging and have discovered that while it says “charging is not supported” with many iPhone chargers that only provide 500ma (the iPad wants 1A or 2A if plugged into wall) it actually does in fact charge, just slower. I have tested two different off brand chargers with the iPad and it works fine, just takes longer.
Tony, you can absolutely do it…just requires a little bit of delicate soldering. We’ll try to show a minitutorial in a week or so on how to DIY an upgrade. meanwhile, go to the parts list so you know what resistors to buy 🙂
I haven’t yet fully read it nor yet looked at which resistor values you had used but I’m betting your circuit ends up being the same as the ones in that spec. anything 35 to 39 k ohms on the “ID_OTG” pin indicates the devie should be a “B” device and it “can connect” Above that… 65 to 72k obms, OTG as b device, can’t connect.
Aha…I think I’ve de-compiled the spec…I’ll have to look at the updated schematics and such of the minty … but I’ll bet you’re seeing/emulating this behavior.
basically to tell a device to limit to 500ma, no more, you can put D- at 0.6V (0.5 to 0.7) — the actual spec says that this is when D+ is at 0.5V to 0.8V. BUT the spec also denotes that for dedicated charging (up to 1.5A) you short D+/D-.
Vbus is supposed to be current limited at 1.5A or 500ma to allow the device to push the Vbus basically down to 2V, this lets the device essentially control the bus voltage to limit power dissipation in the device (if it only needs 4.0V to charge for example the charger circuit might be more efficient at that voltage). Charging ports aren’t supposed to operate at anything less than 500ma through certain voltage ranges (above 2V, less than 4.75V — I assume to cater to USB OTG – realistically though it probably doesn’t matter if you operate within that margin…)
Actual circuit used for an example by the spec is on page 12 (PDF page 18) of the link I posted just earlier. Values for that circuit that aren’t directly mentioned start on Page 27 in the table.(I’ll let you figure out the PDF Page).
Ahhh ok, I hadn’t actually looked at the circuits involved yet, it just struck me that the 49k ohm value you got seemed like it was something I’d recently seen. So I’m wrong. Interesting none the less. I like good engineering challenges 🙂
scharf, some people have older ipods where the battery has worn out and died – but they dont want to spend $$$ to send it off and replace the battery inside 🙂 this keeps old devices rockin’
Hey There! Glad to see a v3 of this. I actually have two v2 minty boosts. Can I just rework the resistors to force 500ma charging? I actually don’t mind paying for a couple of new ones, just would like to salvage the old ones too if possible.
Thanks for all your hard work!
Also I have done some experimenting with iPad charging and have discovered that while it says “charging is not supported” with many iPhone chargers that only provide 500ma (the iPad wants 1A or 2A if plugged into wall) it actually does in fact charge, just slower. I have tested two different off brand chargers with the iPad and it works fine, just takes longer.
Tony, you can absolutely do it…just requires a little bit of delicate soldering. We’ll try to show a minitutorial in a week or so on how to DIY an upgrade. meanwhile, go to the parts list so you know what resistors to buy 🙂
I think that they actually conform to the USB Battery Charging 1.1 spec which is I think part of OTG…
http://www.usb.org/developers/devclass_docs/batt_charging_1_1.zip
I haven’t yet fully read it nor yet looked at which resistor values you had used but I’m betting your circuit ends up being the same as the ones in that spec. anything 35 to 39 k ohms on the “ID_OTG” pin indicates the devie should be a “B” device and it “can connect” Above that… 65 to 72k obms, OTG as b device, can’t connect.
michael, the OTG pin isnt used here – only the D+ and D- lines. the ‘apple style’ resistor string isnt part of the USB charging spec
Aha…I think I’ve de-compiled the spec…I’ll have to look at the updated schematics and such of the minty … but I’ll bet you’re seeing/emulating this behavior.
basically to tell a device to limit to 500ma, no more, you can put D- at 0.6V (0.5 to 0.7) — the actual spec says that this is when D+ is at 0.5V to 0.8V. BUT the spec also denotes that for dedicated charging (up to 1.5A) you short D+/D-.
Vbus is supposed to be current limited at 1.5A or 500ma to allow the device to push the Vbus basically down to 2V, this lets the device essentially control the bus voltage to limit power dissipation in the device (if it only needs 4.0V to charge for example the charger circuit might be more efficient at that voltage). Charging ports aren’t supposed to operate at anything less than 500ma through certain voltage ranges (above 2V, less than 4.75V — I assume to cater to USB OTG – realistically though it probably doesn’t matter if you operate within that margin…)
Actual circuit used for an example by the spec is on page 12 (PDF page 18) of the link I posted just earlier. Values for that circuit that aren’t directly mentioned start on Page 27 in the table.(I’ll let you figure out the PDF Page).
It’s cool that you reverse engineered it though!
Ahhh ok, I hadn’t actually looked at the circuits involved yet, it just struck me that the 49k ohm value you got seemed like it was something I’d recently seen. So I’m wrong. Interesting none the less. I like good engineering challenges 🙂
Good work! Thanks for posting this. It’s helpful to us doing it at home.