CMOS
Introducing the Wrongamin, wrong sound generator.
The Wrongamin is an easy and cheap to build sound maker that I designed to create a range of wrong sounds. From dusty old record crackles to a deep hungry animal growl heard through several out of tune AM radios.
It uses three LDRs (Light dependent resistors) to change the pitch of three very high frequency oscillators. What is interesting about this machine is that in normal operation we don’t hear the oscillators directly as they are tuned far above the highest sound a human can hear. What makes this instrument audible are the interactions between the three oscillators which project downward into the realm of our perception. Some Theramins operate on a similar principle and this is where the Wrongamin gets its name.
“A Theramin can sound very wrong in the wrong hands, a Wrongamin sounds wrong in everyones hands!”
I have drawn up a schematic for the Wrongamin (click above for full size version). As you can see this is quite a simple circuit. You can build it using just one integrated circuit (40106B or 74C14) 3 x LDRs, 3 x signal diodes, 4 capacitors, and 2 resistors. If you want to get fancy and have more gain to drive a line level input then add one more IC and a hand full of components. (See Wrongamin Pic above for all parts needed).
NOTE: if you want to leave out the amplifier section: connect A (oscillator out) directly to input of the Output Section – easy. I have not actually tested this configuration but I have no reason to believe it won’t work. I included the amp section because I want to boost the signal a lot to drive my sound-card’s line input.
Here is a video of the Wrongamin’s first test…
Hope you enjoy, Let me know if you make one!
Leafcutter John.
Handmade Electronic Music – Mini Book Review
Handmade Electronic Music
The Art of Hardware Hacking
Second Edition with DVD
by Nicolas Collins
ISBN 9780415998734
£21.99 (cheaper online)

Beeep Buz-z-z-z-z-z P-p-ping!
First of all I must say that before I read this book I my experience of electronics was very basic. I had begun to get interested in making circuits but didn’t really know where to start. As it turns out this publication is an outstanding introduction.
Nicholas Collins is a composer and performer of electronic music who has worked with John Cage, Alvin Lucier, and David Tudor he is also Professor of sound at The School of Art Institute of Chicargo. It’s clear from the start of his book that this is a man on the same wavelength as the many experimental musicians and artists, the makers and hackers. His teaching style is hands-on, informative and favors the rational of the ear over that of the oscilloscope.
HEM Kicks off Part I with what tools you’ll need to get started and outlines the ‘Seven Basic Rules of Hacking’ which starts out like this”
Rule #1: Fear not!
Ignorance is bliss, anything worth doing is worth doing wrong, and two wrongs can make a right.
Swiftly into Part II which is entitled ‘Listening’ where the subject of ‘Circuit Sniffing’ is introduced. This part covers various ways in which we can listen to and make sound from electrical sources. It also includes detailed how-to’s on: soldering, making a contact pickup, and making an electret microphone.
In Part III it’s time for ‘Touching’ and techniques for making your body part of the circuit are introduces. There is also an introduction to circuit-bending. And a tiny bit of theory (Ohm’s Law – well kind of….)
Part IV is ‘Building’ and covers how to make sound using simple (and cheap) CMOS chips. Various well documented projects progress through: making an Oscillator, Cross Modulation of Oscillators, Feedback Loops, Tone Controls, Gating, Tremolo, and panning signals, amplification, distortion, pitch tracking and even a simple sequencer!
Part V covers ‘Looking’ where sounds are drawn from: IR remote controls and Video signals. He also covers ways in which LCD displays can be corrupted.
Part VI ‘Finishing’ sweeps up the loose ends by looking at making your own Mixers and Mixer matrices (think aux sends), he shows plans for a cheap and simple power amplifier, using sensors to interface with a computer, and a quick look at alternative power supplies including: solar, dynamo, and using transformers instead of 9v the battery power which is used for the projects in the book. At the end of this part is an informative and inspiring look the work of a selection of makers.
The book is rounded out with an excellent set of Appendices. Covering Resources on the web, books and other sources. All the tools and components needed are listed – US suppliers are listed (which is not very useful to most of the world). The ‘Rules of Hacking’ are expended to 25 in number. And finally notes on the DVD which includes links to a million and one interesting web sites.
The DVD has features some of the projects in the book, an artist gallery which gives you some nice examples of other peoples work, and and audio section. It’s not a super slick affair but it gets the job done and is an excellent accompaniment to the book.
What did i think of this book?
Simply put – I love this book, it’s fascinating and informative in equal measure, Collins has the demeanorof a child at play as he talks you through ripping apart CD players, radios, and transforming kids toys into demonic sound makers. He obviously still has a lot of fun exploring sound and sound making. Writing clearly and logically (with a hint of the magical) the ideas raised really do come across in a powerful and inspirational way. Although there is not much in the way of technical speak, there is enough to get you going and the websites listed at the end of the book will take the interested reader further.
My only criticism is that as soon as you start this book you want to start making circuits, It would be amazing if this book came with the components required to build some of the projects.
Want help with the components – Look no further!
Limited “Handmade Electronic Music” Preview via Google Books
Here are a couple of projects which I made from the book:
Have a happy 2010,
Leafcutter John.
p.s. I know it sounds like I’m getting paid to say I love this book. It would be nice, but no.
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