Circuit Skills: Perfboard Prototyping

By Collin Cunningham

Make Magazine contributor Collin Cunningham shows us how to use a perfboard to design a prototype for guitar sound effects. Collin doesn't just make it fun but he makes it look easy.

Build your own Perfboard Prototyping Kit. (P/N 2121092)
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When you think "DIY electronics," one of the first images that likely comes to mind is of parts and wire soldered to a standard piece of perforated circuit board –– and that makes sense. Perfboard is widely used because it's so versatile. Essentially, it's just a grid of potential solder-point connections. You can trim it down to just the size you need or leave extra space for future enhancements, or revisions, if need be.

I demo my own approach to perfboarding by building a rather unusual guitar effect –– the PWM, a design I found in Tim Escobedo's excellent Circuit Snippets collection.

PWM Diagram
In order to get this thing making sound ASAP, I omitted the stompbox switch and its somewhat complex wiring. However, the optional LFO add-on seemed a bit too good to pass up, so I did incorporate that into my build.

I knew from previous projects that the 40106 Schmitt Trigger IC could make some cool experimental synth sounds. It turns out that the chip also works as a surprisingly sweet distortion pedal, if you're into that tough and spazzy fuzz-bot kind of sound (which I am). If you need a boost getting started with your layout, here's a basic diagram of all the on-board connections I made (just much neater than how I actually made 'em).

PWM Board

Perfboard Prototyping Kit Includes:

Qty. Part Description Mfr. Part No.
1 IC, LM386N-1, DIP-8 LM386N-1-R
1 IC, CD40106BE, DIP-14 CD40106BE
1 Transistor, 2N3904, TO-92 2N3904-R
1 Socket, IC, DIP-8, Machine Tooled 6100-8-R
1 Socket, IC, DIP-14, Machine Tooled 6100-14-R
1 Diode, Silicon, Rectifier, 1N4001, 1A, 50V 1N4001
1 Resistor, 47KΩ, 1/4 Watt, 5% CF1/4W473JRC
1 Resistor, 33KΩ, 1/4 Watt, 5% CF1/4W333JRC
1 Capacitor, Electrolytic, Radial, 22μF, 50V R22/50-VP-R
1 Capacitor, Electrolytic, Radial, 2.2μF, 50V R2.2/50-VP-R
1 Capacitor, Electrolytic, Radial, 100μF, 50V R100/50-VP-R
1 Capacitor, Film, Radial, 0.1μF, 50V ECQ-V1H104JL
1 Capacitor, Ceramic, Radial, 0.0047μF, 50V DC.0047
1 Potentiometer, 500K, Linear, 16mm, 1/8 Watt RV16AF-10-20R1-B55
1 Potentiometer, 10K, Linear, 16mm, 1/8 Watt RV16AF-10-20R1-B14
1 Potentiometer, 100K, Audio, 16mm, 1/4 Watt RV24AF-10-15R1-A15
1 Connector, 9V Battery, Safety Snap SBS-IR-1-R
1 Connector, 1/4" Phone Jack, 2 Position, Solder Lug, Panel Mount 11
1 Connector, 1/4" Phone Jack, 3 Position, Solder Lug, Panel Mount 12B
1 Protoboard, 2.4" x 3.4" PCB-102-R

Other Circuit Skills DIY Videos by Collin:

Circuit Board Etching
Function Generator and Enclosures
Fiber Optics
Infrared Light Barrier
LED Color Organ
LED Matrix Kit
Power Supply
Pulse Width Modulation
Surface Mount Devices