With the iPad(like a MIDI keyboard) to their iPads, the next logical question was, "Is there something similar for Android?"
Although it's not advertised or sold by any of the big Android phone manufacturers, the solution is a cheap cable called a USB On-The-Go adapter.
USB On-The-Go (Amazon link), or USB OTG, is essentially a female USB port that plugs into the Micro-USB port of a phone or tablet, allowing you to connect devices that use a standard USB 2.0 or 3.0 connection. In a nutshell, the adapter allows the Android device to be a "USB host," powering and communicating with the connected device.
So far, it's been difficult to figure out which Android devices are compatible with the USB OTG cable. It's clear, however, that the Samsung family of Android phones and tablets are the most USB-friendly of them all, allowing users to connect the greatest variety of USB devices.
Even though USB host mode is technically available in devices running Android 3.1 and above, the hardware manufacturers (OEMs) must enable the feature. And, even then, the OEM might limit the types of USB devices the Android phone or tablet supports.
With the help of this crowdsourced chart, and some of our own testing, we found that the following devices are compatible with USB OTG:
- Samsung Galaxy S II (S2)
- Samsung Galaxy S III (S3)
- Galaxy Nexus*
- Nexus 7*
- Droid RAZR
- Samsung Galaxy Tab
- Acer Iconia Tab A200
- Acer Iconia Tab A500
- Archos G9
- Notion Ink Adam
- Motorola Xoom
- Toshiba Excite 10
- Sony Tablet S
So, it's clear that many Android phones lack support for USB host mode. It's possible that OEMs will include the feature in future software updates, but until then, those who want to hook up USB accessories to their unsupported Android devices will have to root.
*Although the Galaxy Nexus family supports many USB accessories, it does not support mass storage devices, like USB thumbdrives.
Using the USB OTG adapter
There's no set of instructions on how to use the USB OTG adapter, or what USB accessories are compatible with it. So, I unloaded my drawer of USB stuffs and got to work.
When you plug the OTG adapter into your Android device, a quick notification will appear, letting you know that the phone or tablet has recognized the adapter and is ready to be a USB host.
From there, you can start plugging in a number of USB devices. Here are the ones I tested using the Samsung Galaxy S III (S3):
- USB thumbdrive: When you plug in a USB thumbdrive, you Android device will quickly display its contents. You can play movies, play music, and view photos or documents. The interface also allows you to move or copy files from your thumbdrive to your phone's SD card. This is the most practical use of the USB OTG adapter, and an excellent way to quickly transfer files or expand your device's storage.
If, by chance, your device does not recognize the USB thumbdrive, try accessing it with an app like ES File Explorer.
- Desktop keyboard: If you need to do long-form writing, you can use a standard computer keyboard (wired or wireless) to type on your Android phone or tablet. Even shortcuts like Ctrl-A and Ctrl-X will work.
- Mouse: This was pretty surprising -- when you connect a mouse (wired or wireless), a pointer will appear on your Android's screen. With that, you can use the mouse just as you would your finger.
- USB hub: What if you want to connect a keyboard and mouse at the same time? With a USB hub plugged into the OTG adapter, you can do just that. Of course, your battery will drain a bit faster, but the setup might be worthwhile for power users.
- Powered hard drive: Because your Android powers whatever device it's connected to, a portable (not powered) hard drive won't work. However, a powered hard drive will, since it relies on energy from an external source. With the hard drive connected, you can read, write, and transfer any stored files.
- PS3 controller: Now, this is pretty crazy. The Samsung Galaxy S III is stock-compatible with the PS3 controller. As soon as you connect it, you can navigate the interface using the analog (thumb) stick. Most importantly, the controller is compatible with some Android games. So far, the inventory of PS3 controller-ready games has been hit or miss, but Sega games (like Sonic) definitely work.
- Card reader: Photographers will appreciate the USB OTG's compatibility with card readers. In theory, you could shoot photos on your high-quality camera and upload them on the go using your Android phone or tablet. This could also be useful for pro photographers who can show their clients previews or share sneak-peeks of photo shoots through apps like Instagram.
- DSLR camera (Canon T3i): The OTG adapter coupled with your dSLR's USB cable allows you to tether your camera to your phone or tablet. Using an app like Remote Release or DSLR Controller, you can even use your Android device as a remote shutter release, as well as control camera settings and mirror them live.
- USB-to-Ethernet adapter: If Wi-Fi isn't available, or you want a supersteady Internet connection, you can connect a USB-to-Ethernet adapter ( ) to your USB OTG and connect the phone or tablet to a wired Ethernet connection.
With time, more Android devices will likely support USB hosting. If you discover any additional devices that support the USB OTG adapter, or other USB accessories that work with it, let me know in the comments.