This document describes an aid invented by the author for teaching binary computer concepts in a data processing course for business students unfamiliar with mathematical concepts. It permits the instructor to simulate the inner, invisible operation of storing data electronically. The standard 8-bit "byte" is represented by a portable "light-board" containing eight small light bulbs, each equipped with a switch for independent operation. With all bulbs off, the board corresponds instructionally to a bit configuration for a computer card column. A 1-punch can then be represented by switching on the right-most bulb and affixing a label containing the digit '1' to the bulb. The instructor can then explain that this bulb has been used in both its states (on/off). Instruction proceeds by repeating this process with other bulbs. The device can also be used to demonstrate Hollerith and other coding systems. Complete schematics for building the unit are appended. (Author/RT)