Keith's Electronics Blog

Here’s my prototype of the circuit on a solderless breadboard:

And here’s the board layout.

A few notes:

• The blue traces represent the connections that are already built into the breadboard. The red connections are wires plugged in on the top.
• The LM339 goes upside-down from the normal orientation, with the dimple or dot at the right end.
• My speaker potentiometer is connected via wires, not mounted directly to the board as shown in the layout. Yours can be, too
• I connected a speaker-like signal with the clips at the left of my breadboard. Yours would be wired to the speaker jacks.
• I didn’t install the right speaker input and potentiometer on my prototype, so there’s a gap in the lower left where they’d go.

With those few issues in mind, this should give you enough information to assemble your own.

Part 0: Project Overview
Part 1: Schematic and Operation
Part 2: Parts and Enclosure
Part 3: Layout and Prototype
Part 4: Construction and Calibration

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