MintyBoost v3.0 acting strangely

[idkwat2namme]

I just finished putting the MintyBoost together and I am getting some strange results.

It works with an iPod touch (works every time I plug it in), but when I use it to charge my 3GS it did not work. I got the "Charging is not supported with this accessory" error. I soldered the 2 data pins together and I got the same thing.

After looking at the forums for a while I saw that someone just unplugged and plugged in their device to get it working. That is what I did and it worked. The problem is that every time the first time I plug in the MintyBoost the error pops up then I unplug it and plug it in 5 or more time before it works.

I did plug the chip in backwards initially then I flipped it around and it worked. Any help or suggestions?

Update: Mintyboost charges a 3G and no longer charges a 3GS. While repeatedly pluging and unpluging the Mintyboost, the charge icon may come up but is always then followed with the error...

[idkwat2namme]

I took a closer look and maybe someone has some answers. The data lines start at 1.979 V then drop to ~1.83 V when I plug in my 3GS. Is this causing the problem? I think that could be the reason I get a charging icon for a split second then it gives me an error. I got the MintyBoost for a 3GS and it doesn't work with my 3GS (Did I maybe damage the chip when I plugged it in backwards and powered it on?). Can anyone help me???

[adafruit]

did you read the thread
viewtopic.php?f=15&t=11661

[idkwat2namme]

did you read the thread
viewtopic.php?f=15&t=11661

Now I have... I am having the same problem where the battery voltage is dropping too low and that pulls down the data lines. So I hooked up another battery in series and, what do you know, it works every time.

But is this really a fix? I'm just saying the MintyBoost does work for others with 2 AA batteries, why isn't it working for me? Additionally, I do get the correct voltages out of the power and data lines before anything is plugged in. The voltages are dropping too low when the 3GS is getting plugged in. Is there a fix for that, maybe bigger capacity(C or D cell batteries). I am just thinking the product was designed to boost 3V, and the fix I am applying it taking that voltage up.

I like this stuff and I love asking questions, that's how I learn. Don't get me wrong I like the concept of this product. It's not some other charger, it is one you made. That's cool. I want to absorb some knowledge from this.

Thanks!

[deltafalcon]

So I hooked up another battery in series and, what do you know, it works every time.

Whilst I didn't check to see what the battery voltage was when this was happening, hooking up another AA in series fixed this issue for me as well, until the batteries were drained enough to start sagging again... My electronics theory is a little shot but would this be as simple as adding another capacitor to try and negate the sag in voltage? It only happens for a few seconds but the iPod refuses to recognise it after that. Re-plugging doesn't help as the sag happens again. It appears to be an issue with the batteries used, at least from my testing.

I tried cheap and midrange batteries and when I get my hands on some high end lithium "for high powered devices" types, I'll let you guys know. I have a suspicion that cheaper batteries aren't able to keep up with the demands of the iPod which may be causing a lot of these issues. If I get my hands on some Sony Eneloops as well, I'll try 'em.

This problem was occurring with my iPod 3rd Generation (MC008ZP). On a happy note, the Minty Boost v3.0 appears to work perfectly with my Huawei IDEOS U8150 phone, an Android 2.2 device (something that could be added to the compatibility list). I don't have access to an Altoids tin in Australia (nor could I afford it at the time of purchasing the kit, go figure...), but there is an Australian mint that comes in a metal container as well, called Eclipse by Wrigley. It fits the Minty Boost v3.0 almost perfectly (with a bit of lateral thinking, of course) but is a little bit tight. I'll also report back my findings with that (inc. pictures of the build) when I finish all of my damn assignment work.

The real test for this will be 2x nine hour train/bus trips two and from Sydney next week! I just hope Minty Boost, many episodes of The Big Bang Theory, Burn Notice and mobile data can save me!

[adafruit_support_bill]

would this be as simple as adding another capacitor to try and negate the sag in voltage?

A large enough capacitor might help smooth over a very brief sag, but once it is drained, it is all up to the batteries (which now have to work harder to recharge the cap!). Many recent devices with high-capacity lithium batteries use charge rates that are at the upper limits of what the MintyBoost can do. To charge these devices you really need to use batteries that can supply enough voltage to keep the boost converter working efficiently.

The batteries page of the MintyBoost tutorial has a lot of good detail on battery options: http://www.ladyada.net/make/mintyboost/power.html More cells in series is one option. Larger cells (C or D) is another.