Phone to access memory card

March 29, 2012 10:47 AM

Can I connect an external memory stick or memory card to my phone? (with an adapter)

The answer's no I think - but does anyone sell an adapter or dongle that would allow me to access data on a memory card or stick that's attached to my smartphone? Imagine - for example - I could take the memory card out of my camera and plug it into my phone and access the photos from the phone. Or plug a USB memory stick into the phone to access a stored document.

It seems like a useful feature to have, but I can't find a device to buy that would let me do that. Help please.

I realize I have the micro-SD slot inside the phone (assume I'm using a fairly recent Android phone), but swapping cards is a bother and messes up all sort of things. The phone has a micro-USA slot - it is useable to access external memory? If not, is there a technical reason why these things are not available? I guess when I plug the phone into a computer, the phone becomes the 'memory card' - I want it the other way around. An adapter that lets the phone read an external memory card.

Thanks

posted by Xhris to technology (5 answers total)

Your phone need to support USB On-The-Go and you'll need a hard to find cable.
posted by Confess, Fletch at 10:52 AM on March 29, 2012

This is more handwavey than I'd like, but:

You'd need, at minimum, a micro-USB-to-Standard-A receptacle cable (to plug the flash drive into). These are non-standard because you're connecting two "devices" together (something with a mini- or micro-USB receptacle is a "device." If it has A receptacles, it's a host that can connect to other devices).

You can get micro-SD - to - SD adapters. You slot the microSD card into a big SD card, plug that all into a camera. Then you might be able to coax your phone into viewing the pictures by plugging the microSD card into it.

On preview, oh, didn't know there was actually a standard for connecting devices together. That would do it, but you'd be very lucky...
posted by BungaDunga at 10:57 AM on March 29, 2012

Hmmm, the cables don't seem impossible to find though.
posted by Confess, Fletch at 10:58 AM on March 29, 2012

It looks like Android doesn't automatically mount USB mass storage devices. But there are apps that will allow it. You'll also need the cable.
posted by aubilenon at 11:55 AM on March 29, 2012

You'll need one of the newer Android phones supporting USB on-the-go. You will also need a USB on-the-go cable. This is NOT just a converter cable between the two port sizes, so one of those universal USB adapter things won't work (trust me, I tried). The real OTG cables have an extra pin with a specific resistance value that puts USB OTG devices into host mode. You can hack your own cable, if you're stupid or already have one with the wrong resistance; but, you should just order one. (Incidentally, you won't find one in your town, either. I tried 3 different converters that all appears outwardly identical. They were not inwardly standard, and did not work.)

Your phone will also need to run a reasonably recent version of the OS. To get any sort of android-level support, it must be ice cream sandwich. With the app aubilenon links to, there's apparently some kind of support for android phones with USB host controllers running the 2.x series OS--but, I wouldn't expect it to be very excellent. Lots of those not-sold-as-usb-otg phones don't properly initialize the chips. Some even have USB OTG chips, but don't route the hardware lines for the host controller functionality (usually, it's that the phones don't supply power to attached devices, which you *might* be able to overcome with some creative cabling and an externally powered USB hub).

Anyway, I just now tested the app linked, and it works flawlessly to mount an external micro-sd card reader on my Galaxy Nexus using a $5 monoprice.com USB OTG adapter.

Oh yeah.

Your phone must be rooted for basically any of this to work properly.
posted by Netzapper at 4:05 PM on March 29, 2012