There's a lot of micro miniature PC units available secondhand now that are used a lot for advertising displays, as well as being sold new for industrial use and for enthusiasts, mostly based on Atom Mobile (1.1Ghz) with a Micro SD card reader (2 slots) a Compact Flash slot (x1) and 2 USB ports, built in wi-fi 802.11b and built in graphics, they have a single head standard graphics output (VGA DE15) and a composite video out (which can be fed into a scart converter that can be bought in Tesco for 89p) most of these these(current) units have a basic Audio output in the form of one 3.5mm stereo jack, and the operating Ram is 1 x 2GB DDR2 SODIMM(Small outline Dual inline memory module) which can be changed out usually up to 4GB, there are some units with a spare memory slot which can be expanded but they all come supplied with just the one card when first sold...
These units are about the size of a DVD box cut in half in the middle and can be interfaced to a Hard Drive, they will also boot from a memory card and/or a USB memory stick (64GB ones are quite cheap now, they are sold up to 128GB at the moment but quite expensive) and can provide enough current to run a 2.5 inch Hard Disk Drive (laptop drive) they can also be internet connected via wi-fi, USB Dongle(such as Vodafone , 3 Mobile or O2) and via the Ethernet (RJ45)port to a wired network....
They will boot into and run windows 95, windows 98, windows ME, Windows 2000, Windows XP, Windows 7, Linux, UBUNTU and with a bit of trickery will even run versions of MAC software (quite a bit of extra set up work involved) setting up windows 8 is not something that I have heard of yet, haven't tried it myself...could be hardware issues that would take time to iron out...
As well as these computer units, if you are very lucky, you can bag one of the displays as well on ebay (think of the rectangular ones in the windows of Orange mobile phone shops and on floor standing displays in department stores) and there are pub touchscreen jukeboxes as well, I nearly bagged one from a pub that closed but it was skipped along with all the other stuff before I got there...it was running windows XP Shell with in house mediaplayer software and a cut down version of windows mediaplayer from the manufacturer, this would have allowed me to stream online music and access my stored music and would have looked great on the wall....
These units have similar capabilities to a cheap netbook computer, the built in graphics are quite good but only the newest ones sold for about the last 6 months(hence none going secondhand)have an HDMI Port.....the graphics chips in these miniature computers have a high refresh/strobe rate and fast memory as they are intended to run video content by design (originally intended for advertising displays)
Power requirements - usually a 5V DC to 12V DC 200mA supply, so will run from batteries.
Interface- Keyboard and/or touchscreen interface via USB
Connectivity: 802.11b wi-fi, USB, RJ45 Ethernet 100Mb, a small 4 port USB Hub can be connected to one of the USB ports for expansion, Bluetooth mini USB dongle will function...
Graphics: VGA and composite Video out(works with Scart Adapter) this can also be connected to a projector and used as an internet surfer clipped onto the side of a ceiling mounted projector, handy space saver...
Audio: standard Stereo, will drive headphones, or speakers via a small external amplifier.
RAM: 2GB DDR2 (Expandable) Also USB Memory stick can be partially shared as operating memory.
Will run any capacity 2.5 Inch Laptop HDD (solid state SSD not advised due to set up issues and slow speed)
They can be picked up for as little as ÂŁ25.00