DIY

CIRCUITS

BREADBOARD RACK

A simple way to interconnect protoboards.

By Tom Zimmerman

Solderless protoboards are a convenient way to build electronic circuits, but interconnecting several boards gets messy. Adding input and output (I/O) components such as switches, potentiometers, jacks, and LEDs requires drilling, wiring, and stuffing it all into a box, where it’s hard to debug and modify.

Photography by Tom Zimmerman

A nicer approach, which I borrowed from early analog synthesizers, is to build handy modules that carry one protoboard each and plug into a rack. Each module carries its protoboard underneath, and the circuit’s I/O components are on a visible and easily reachable front panel, just like any other device that hides its complex circuitry inside and exposes only the controls and connectors.

The front panels are made of pegboard, providing predrilled guide holes for accurate alignment of module components. The rack holds 14 modules,

7 on each side. Wider modules can be built to accommodate larger protoboards. Angle iron rails both hold the modules and supply power. The top rail supplies modules with unregulated + 12 volts, and the bottom rail supplies electrical ground. Magnets behind copper contacts on each module grab the rail, hold the module in place, and provide a large surface area to deliver plenty of current. Each module must have a power diode, for inevitably a module will be accidentally installed upside down. Additionally, a voltage regulator on each module assures a clean and stable power supply.

Before you start, remember these important safety tips: wear eye shields when working with power and hand tools, gloves when cutting metal and applying hot glue, and a dust mask when sanding and cutting.

Make: 127