4 ms·

There is one easy way to solve this problem that I can think of: Neuter a USB cable by shorting the data pins on the device end and disconnecting them on the ch

by gwillen 14y ago

There is one easy way to solve this problem that I can think of: Neuter a USB cable by shorting the data pins on the device end and disconnecting them on the charger end. Just be careful not to plug the resulting cable into a computer -- you are likely to draw more current than permitted by the USB spec, and could potentially cause an issue. (I suppose you could potentially cause an issue with a charging kiosk too, if it's a computer rather than a dumb brick, but it's not really the kiosk I'm worried about.)

raverbashing 14y ago
Do you need to short the data end at the device? Probably not It may make sense to not leave them "floating", not sure how chargers do (I mean, not considering the ones that do some electric tricks for the device to recognize their "vendor extensions")
- gwillen 14y ago
  If you want a standards-compliant 'fast charge', you need to short the data lines to the device. If you merely cut the data lines, I don't know what the device will do. Probably it will draw 100mA, which is the permissible draw for a USB device that hasn't connected to the host yet, and then it will repeatedly try and fail to connect.
maxjus 14y ago
I know that some modern iOS devices actually require a specific voltage across the data lines to tell the device what wattage charger it's using. In that situation you would have to add a couple of resistors to the charging cable between the voltage and data pins, which definitely makes it a lot more difficult for most people. You might find the following interesting: http://www.ladyada.net/make/mintyboost/icharge.html http://www.ladyada.net/make/mintyboost/icharge.html
- gwillen 14y ago
  You're right -- as an Android user, I was thinking about the USB 3.0 charging standard (and the pre-standard behavior which led to it), which Android devices generally follow. If you have an iDevice, you have more work to do.

by gwillen 14y ago

raverbashing 14y ago

Do you need to short the data end at the device? Probably not It may make sense to not leave them "floating", not sure how chargers do (I mean, not considering the ones that do some electric tricks for the device to recognize their "vendor extensions")

gwillen 14y ago
If you want a standards-compliant 'fast charge', you need to short the data lines to the device. If you merely cut the data lines, I don't know what the device will do. Probably it will draw 100mA, which is the permissible draw for a USB device that hasn't connected to the host yet, and then it will repeatedly try and fail to connect.

maxjus 14y ago

I know that some modern iOS devices actually require a specific voltage across the data lines to tell the device what wattage charger it's using. In that situation you would have to add a couple of resistors to the charging cable between the voltage and data pins, which definitely makes it a lot more difficult for most people. You might find the following interesting: http://www.ladyada.net/make/mintyboost/icharge.html http://www.ladyada.net/make/mintyboost/icharge.html

gwillen 14y ago
You're right -- as an Android user, I was thinking about the USB 3.0 charging standard (and the pre-standard behavior which led to it), which Android devices generally follow. If you have an iDevice, you have more work to do.