What’s Inside

AndOrBit is a set of partly-assembled printed circuit boards with additional parts you assemble using a soldering iron (not included).

There’s a “motherboard” (11.5” x 5.5”), and 8 “daughter boards” (1.7” x 4.5”), plus a pair of tweezers and a strip of a thousand diode components. A DVD of assembly instructions is included.

The daughter boards are a sandwich of two outer boards and two inner boards. The inner boards are spacers that form the logic matrix. The outer boards carry the electronic components and electrical contacts. Four quarter-turn quick-connect fasteners hold the two boards together.

The matrix has 8 rows and 33 columns of holes. For 32 columns, a logic “AND” function is created by dropping diodes into the proper holes of a row. These holes are specified by logic equations (or expressions) that you write to define the intended operation. The last column is the “OR” column – diodes in these holes define which of the AND terms are combined by the OR function to generate the input to one bit of an eight-bit latch on the motherboard.

Columns are organized in two groups of 16 on the matrix – one for latch outputs and the other for board inputs. Each group of 16 consists of 8 pairs – with each pair consisting of an input or output signal and its complement (NOT). Once the diodes are in the intended matrix holes you reassemble the sandwich by fastening the top board to the bottom set of boards using the quarter-turn fasteners.

Eight LEDs on the edge of the top board display the status of the AND terms. This is to help with debugging.

Inputs are set by eight slide switches on the motherboard. Eight yellow LEDs, each in front of the corresponding switch, display the input value.

Outputs of the latch are displayed by green LEDs immediately in front of the input LEDs. Two pushbutton switches allow the user to advance through states (Clock) and reset to an initial state (Reset).

A 48-pin data connector on the board edge carries signals allowing external devices to control and be controlled by the motherboard. The board is powered by an external power supply of from 7.5 to 12 volts DC, which may be unregulated or regulated.

An 8-bit DIP switch selects which of the bits go through the latch and which bypass it. This allows for the implementation of more complex logic functions.