this is a diagram, of sorta a msc, using relays, and parts you can get from radioshack, and you lhs.
the blocks are relays, the triangles are from the 339, the bottom of each triangle is - . the wigley lines are resistors, which values i dont have the time to explain. this is a fairly simple curcuit, though it still requires parts, and time and effort. this will prove how much you are willing to go through to save the money for electronics for the r/c cars. uh, theat probably didnt make much sense, i fried my brain making up that curcuit
. if you are interested in usin it, pm me, and i will give you much more detaals. and other electrical engineers: any problems with this?