Daniel Dadap wrote: > Hello Community, > > I just bought a portable USB battery pack ( one of these: > http://apc.com/products/family/index.cfm?id=314 ) to use with my > FreeRunner so that I could keep tangogps running to log a track for me > during a bike ride. It worked quite well: I was able to keep the unit > powered on for over 12 hours and still had some juice left over to > make some phone calls at the end of the day. However, I noticed that > the FR was only drawing 100mA. I was sort of hoping that the battery > pack would emulate a USB host and negotiate current, but it looks like > it just has available power. > > Anyway, I saw on http://wiki.openmoko.org/wiki/USB_charger that the > included AC adapter has a 47.5 kOhm resistor betwen ID and GND. Like > many other people on this list, I have dozens of USB A to Mini-B > cables cluttering the house, and I figured it might be a neat idea to > cut a cable, splice it short (about 20cm or so), and add a resistor. > This cable would be used only for charging with the battery pack. I > don't like the idea of having to switch the FR to force fast charge, > possibly forgetting to switch it back before plugging it into a > computer, and possibly destroying the USB port on the computer and/or > the FR. A dedicated charging cable would make this simpler. > > Problem is, the ID pin apparently exists only on the Mini-B connector, > and doesn't have a corresponding wire inside the USB cable. Has > anybody on the list done USB connector hacking, and have any tips on > how to get a resistor in there without interfering with plug in > operation? > > Also, what part of the software exactly is responsible for charger > detection? I guess another possibility is to hack the software to > recognize shorted data pins as a charger. I have another device with a > charger that identifies itself by shorted data pins, but more > importantly, shorting the data pins is a much easier mod to perform on > a USB cable. > > I suppose the easiest option would be to cut off the end of a FR > charger (or other compatible charger with a resistor across GND and > ID) and splice it with a USB cable... but I would like to hear other > suggestions that people may have.
1. I'm working on an adapter using a 5 pin mini USB connector from Digikey (p/n H2958-ND CONN PLUG MINI USB2.0 5POS ) 2. Belkin makes a 5-conductor mini-USB to USB cable, useful as a start for another hacking project. http://catalog.belkin.com/IWCatProductPage.process?Product_Id=128038 3. It's possible that the ID resistor in the FR charger is in the wall-wart portion and not at the mini USB connector. 4. I'm composing a detailed wiki page to gather all of this info, and I welcome contributions. _______________________________________________ Openmoko community mailing list community@lists.openmoko.org http://lists.openmoko.org/mailman/listinfo/community