Listening to Signals

When beginning electronics, fancy equipment is not entirely necessary. You can make many interesting, instructive circuits using just a breadboard and through-hole components. (Check out Charles Platt’s Make: Electronics and accompanying component kits to jumpstart your new hobby. The book promotes “Learning by Discovery,” guiding you through building 36 electronics experiments using over 500 full-color photographs spanning 300-plus pages!)

Yet there comes a point when a bit of familiarity with testing equipment is necessary, or you simply want to take your hobby to the next level. Perhaps you want to investigate further what is going on in your projects, to troubleshoot a circuit design, or even visualize the timing of a Pulse Width Modulation (PWM) signal (check out Collin Cunningham’s PWM primer for more on this subject).

Visualizing signals is where an oscilloscope comes in handy. The only problem: even entry-level oscilloscopes will set you back a few hundred dollars, and since you’re a beginner, you might not know exactly what you need (or want to spend those hundreds of dollars). You want a cheap alternative, preferably one that is DIY, and perhaps even uses relatively familiar hardware, like say…your sound card!

We call it the Sound Card Oscilloscope, and you’ll definitely want to build and add this project to your growing arsenal of maker tools. The project plugs in to the line-in jack on your sound card. Combined with a carefully crafted circuit from Ryan Slaugh, and a robust software package (Windows only, but it emulates fine for us in Winebottler for OSX), it’ll wrangle all the data in your project up to a rate of around 44kS/s. You’ll be listening to signals in no time!

See it in action in the video below, and let us know if you wind up building this or any of our other beginner-friendly Weekend Projects.