I don't agree at all with the previous poster who suggested that
you not make a harp because it is "too hard." Nothing is really
ever too hard. It's just a matter of finding a project that works
for you. A harp is only an angled or triangular frame attached to a
resonating box (sound box), with strings that run from the frame,
into the box. That's all. From there, it can be as simple or as
complex as you want it to be. I wouldn't try to make a concert
pedal harp for a school project, unless you are going for a high
school engineering project and know a bit about acoustic
engineering and physics, but that doesn't mean a harp of some kind
isn't a possibility. After all, there are about as many types and
styles of harps as there are cultures. Without knowing exactly what
you are looking for, I recommend a book called "Cool Cardboard
Instruments" by Dennis Waring. There are some simple harps in
there. (You can even preview it on Google books.) His "Making Folk
Instruments from Wood" is also very good and has a more advanced
set of plans for a Celtic harp. If you need them, there are also a
lot of more advanced woodworking projects that people have shared
on the web. For instance: http://gnomonkeep.org/harp/harplog.html
http://cavender.myweb.uga.edu/harp_project/