The PT501 from 1979 was the course name of the Open University's first foray into microcomputer training. Like the MicroProfessor it was a similar (but much simpler) single board computer featuring an Intel 8049 CPU that you programmed in Hex to make the 2 digit display tell you important stuff about what the machine was doing. There's also two sets of 'traffic lights' for the student to learn how to program. Like all Open University hardware it was supposed to be returned at the end of the course, but I'm guessing not many people did that unless they just weren't interested.

This one came from often missed correspondent Lee Davison (RIP) and contains an 'experiment book' as well as a set of brochures that are supposed to give the student an idea of the Great World Of Computers even if you ARE just programming some traffic lights. I really should replace the power socket one day, I don't think I've ever powered it up.