The HP TouchPad tablet features a 9.7 inch screen, a 1.2 GHz Qualcomm Snapdragon processor, and 1GB of RAM. While HP discontinued the tablet just a few months after launching in in 2011, there are a few million of the tablets in the wild… and owners keep finding new and interesting things to do with them.
Xda-developers forum member mpgrimm2 has modified his tablet to feature a USB OTG (On The Go) port which lets you plug in a USB mouse, keyboard, flash drive, or pretty much anything else.
This hack also lets you send power to USB peripherals — which means that you can use the HP TouchPad’s battery to power accessories that need power. It also means that you can use your TouchPad to charge your phone or other items that can charge over a USB connection.
That said, this is not an easy modification. It involves disassembling the tablet, drilling holes in the case, soldering electronics, and all sorts of other scary things. If you’re not comfortable doing those things (or comfortable with the idea of killing your tablet), you might want to just buy a new device that already offers USB OTG support.
You can find detailed instructions on adding a powered USB port to the TouchPad at the xda-developers forum.