Much in the spirit of StarTools, Rowland Cheshire has been working hard on making that other part of the astrophotography equation more budget friendly and accessible; image acquisition.
On his site you will be able to find detailed plans for building your own Tangent Error Minimized, Double Arm Drive. His design uses the latest developments in user-friendly DIY electronics to improve the classic 'Barn Door Tracker' design.
If you are looking for a low-cost solution for long(er) exposure photography and a bit of DIY doesn't faze you, I heartily recommend you have a read!
http://www.synergous.com/flatpress/inde ... arm-drive/