This circuit is a fork of a great project that I found online while looking for information on Linear Feedback Shift Registers (LFSR).

Here’s a video that inspired the fork:

The circuit sounds much more like an Atari 2600 than the ever-popular Atari Punk Console, or Stepped Tone Generator for you Forrest Mims fans.

While I was not looking to clone the circuit , it did lead me to use it as a base for building one that was little bit more fleshed out.

Here’s the schematic I came up with:

[caption id=“attachment_680” align=“aligncenter” width=“300”]atari-punk-junk-console A complete circuit that sounds a lot more like the vintage Atari 2600 than the famous Atari Junk Console![/caption]

Nothing too complicated, right? Well, if you’re new to building your own circuits and maybe learning a little design, keep reading for an in-depth analysis of what’s going on in the picture above!

The Breakdown

Overview

I’ve nicknamed this circuit the Atari Junk Console .

Clock Generator

[caption id=“attachment_681” align=“aligncenter” width=“300”]atari-punk-junk-console-555-astable-timer To get this circuit going, you’re going to need a 555 astable multivibrator. It’s just an oscillator that generates a metronome-like beat.[/caption]

Gated Oscillators CV Source

[caption id=“attachment_682” align=“aligncenter” width=“300”]atari-punk-junk-console-gated-4093-oscillator Using two of the most basic oscillators you can DIY, this particular circuit works great to modulate our main LFSR circuit. It also sounds pretty cool on its own.[/caption]

Linear Feedback Shift Register & Output

[caption id=“attachment_683” align=“aligncenter” width=“300”]atari-punk-junk-console-lfsr-linear-feedback-shift-register The main noise generator for our circuit. The basic circuit at play here is a Linear Feedback Shift Register (LFSR), a test circuit widely used in electrical engineering.[/caption]

Power Supply

[caption id=“attachment_684” align=“aligncenter” width=“300”]atari-punk-junk-console-power-supply The power supply is a standard way of offering two different power sources (battery and AC Adapter) and then regulating them to a nice, steady, low-noise 5V. The switch is the master on/off for the circuit.[/caption]

Power Supply Filtering

[caption id=“attachment_685” align=“aligncenter” width=“300”]atari-punk-junk-console-power-supply-capacitors If you’re dealing with oscillators and AC Adapters, it behooves you to filter the power supply. You don’t want excess noise to interfere with your sounds, especially when sampling/recording![/caption]

Unused Gates

[caption id=“attachment_686” align=“aligncenter” width=“300”]atari-punk-junk-console-unused-gates Always ground your unused CMOS gate inputs![/caption]