Our experience during these 10 years has shown to us that the fundamental concepts of "how computers are built" are simple enough to be taught to high-school students (and could even start from elementary school), and that is what we now want to develop. We have recently strarted developing a new generation of educational boards and kits for this purpose, based on a novel concept. The new concept on which we base this generation of educational lab equipment relies on our observation, during the last 10 years, that the concept of Random Access Memory (RAM) is: (a) of central importance, (b) not immediately obvious to a teenager, and (c) easy to explain if one starts with crossbar-shaped wires with jumpers (and diodes) at the crosspoints that store a "1" value. The junior students in our University class required considerable effort in order to grasp the concepts of: (encoded) addresses, (decoded) word-lines, data words as memory contents, and bit-lines. In turn, these concepts of addresses versus data are of central importance to all of computer science and programming. Also, notice that a Read-Only Memory (ROM), which is the first step towards a RAM, is in fact the truth table of an arbitrary combinational circuit. Thus, instead of starting to teach digital design in the traditional way using AND - OR - NOT gates, we now want to experiment teaching it to high-school students in this novel way, teaching the folowing two concepts first: (1) crossbar-shaped wires form a ROM - use this ROM to control a 7-segment display; and (2) a binary tree of relay switches forms a decoder - use it to decode an arbitrary user code that drives the ROM, then displaying the desired decoded message (this is the introduction to address decoding). We are planning for three pieces of equipment: (a) a board for familiarizing the student with electric circuits; (b) a crossbar-ROM; and (c) a device that emulates a programmable ROM or a RAM and allows the student to build larger systems - even a simple processor. We have built a prototype of (a) and one of (b), and we are now developing a prototype of (c).
The crossbar ROM (b), is better described, with related photographs, here.
