Using a barndoor tracker is a great way to start doing astrophotography with your DSLR camera. The tracker can be built to run manually or it can be motorized.

I originally started with a manual barndoor tracker. The inspiration for the design of the manual barndoor tracker is from Stephen Tonkin and Philip Harrington:

http://www.astunit.com/tonkinsastro/atm/projects/handscotch.htm

http://www.philharrington.net/scotch.htm

Recently I decided to motorize the tracker to see if I could get better performance with long focal length lenses. The current version is motorized using a 7 RPM motor with a simple rubber band drive belt with a wooden dowel for the motor “gear” and a Skippy peanut butter lid as the “gear” for the drive screw. The inspiration for this design is from K.P.Trout at Penn State University:

http://www2.yk.psu.edu/~kxt7/Barn%20Door/BarnDoor.htm

The key components used are as follows:

High Torque Motor, 7 RPM, 3V Edmund Scientifics #78847

RadioShack 2AAA Battery Holder #270-398B

RadioShack Toggle Switch #275-0612

Parts Express 1K Ohm Potentiometer #023-510

Male/Female wire connectors are used for flexibility in adjusting location of components, as well as making it easy to reverse direction of the motor. The drive bolt mounting socket is liberally greased to ensure smooth operation.

Many other more sophisticated designs can be found on the internet which may result in even better performance.