MAKE Weekend Projects - Optical Tremolo Box

[Video Link] Check out Charles Platt's cool Weekend Project for MAKE: an optical tremolo box. Built by MAKE's tech editor, Sean Michael Ragan.

Inspired by Charles Platt's "Stomp Box Basics" article (MAKE Volume 15, page 82), follow along as we build this Optical Tremolo Box, which reads a patterned disk with a light sensor to create a warbling audio effect (tremolo).

For this project, MAKE Technical Editor Sean Ragan used a cadmium sulfide photoresistor to provide us with our light sensor - a component we have used in previous Weekend Projects. Not only does it look cool and sound great, but once you've made the project, you can customize it by making your own effects disks!

Complete instructions for this episode of Weekend Projects

Mark Frauenfelder is the founder of Boing Boing and the editor-in-chief of MAKE and Cool Tools. Twitter: @frauenfelder. Come and hear Mark speak at the ALA conference in Chicago on July 1.

More at Boing Boing

Eurovision 2013: An American in London

The technology that links taxonomy and Star Trek

xzzy

Not to make it sound like this creation is any less awesome, but there’s an existing tremolo pedal out there that uses light.. it’s the Danelectro Chicken Salad. You can’t really tweak the pattern though.. it’s buried in the pedal. Little tiny light bulb inside a little box of photo-resistors. Turn the pedal on, and the light bulb pulses in a rhythm.

Interesting part being is it’s generally considered the best low-budget tremolo out there. Since this custom build lets you directly adjust the light pulsing I guess that means there’s a new “best”.
- yoshua
  
  As was pointed out in the youtube comments, there are even earlier examples of optical tremolo in some organs, but I’ve never seen anything that let’s you make your own disks!
  - http://twitter.com/smknghrtdesigns SmokingHeartDesigns
    
    Could use 2 disks that rotate at different rates and intersect.
- latelatelateshow
  
  I’ve misplaced my cadmium sulfide photoresistor. Can I use an old piece of chewing gum instead?
  
  The Danelectro line of effects pedals is smart and designed with elegance (as always) – Of course with any discussion of musical effects boxes, pedals, etc there will be some biased towards store-bought and some biased towards soldered and electrical tape-built custom items. To me it doesn’t matter as long as I can annoy my bad neighbors with a one man guitar army version of “Rumble” at 6 AM on a Sunday. A little Link Wray can go a long way.
Antinous / Moderator

At first, I thought that it said optical trololo box.
- fuzzyfuzzyfungus
  
  Coating amusing Russians in cadmium selenide is hardly humane, now, is it?
- Paul Renault
  
  Damn you! I came here to say this!
http://twitter.com/smknghrtdesigns SmokingHeartDesigns

Cool pedal, has good sound. Hacks: use an aluminum enclosure and avoid screw terminals. Screw terminals always come loose and plastic boxes are top-heavy and they break when you step on them.
Angryjim

Reminds me of the drum buddy: http://www.youtube.com/watch?v=vvtssL8WlJA
- http://www.commodorecrush.com/ Commodore Crush
  
  That’s what I thought when I saw this post. I’ve seen Mr. Quintron a handful of times and it’s amazing to watch him scratch on the Drum Buddy.
- bagoombah
  
  I need this to play while I brush my teeth with my Bathroom Buddy. The invention of the century, friends. It eliminates the need to carry heavy luggage and things when you travel. You got yourself your shaving mirror. You got yourself your toothbrush. You got yourself a toothpick, you got toenail clippers. You got… nail file. You got yourself a dental mirror. This is gonna revolutionize traveling.
MikeJones1208

Perhaps this method could be used to vary other effects over time.
- Tim Drage
  
  It could indeed. I have an ultra cheap Danelectro FAB Echo to which I added an LDR to control the echo speed (it’s originally a slapback echo with absurdly no control over the echo time at all!), goes all the way down to low bitrate crunch and makes pretty interesting sounds if you put it next to a strobe light/bike light etc…
http://twitter.com/tadasyoyolt Tadas Jelinek

Ahh.. Saw something like this in one gig. Problem was that it looked so cool that everybody started taking pictures using flashes and every flash caused a sharp loud pop in sound of that instrument. Keep this in mind before taking this to a live gig ;)
- fuzzyfuzzyfungus
  
  Shrouding the system to protect it from optical interference wouldn’t be too difficult, though it would probably ‘solve’ the “looking cool” bit at the same time, unfortunately…
Scatter

Also check out the wonderful Leafcutter John’s experiment with light and sound:

http://leafcutterjohn.com/?p=1680
SamSam

This looks very cool. I can also see having a whole line on light-controller boxes. Volume? Just turn up that light over that photoresistor over there. Sure, it’s at’s a little more convoluted, but it sure looks cool!

For those who want to actually hear what this thing sounds like, skip all the way to 8:10 in the video. I notice Make videos often just describe the thing at first, and don’t actually let you see/hear what the actual final product will be.
Preston Sturges

He’s using the file wrong. Since his file is half round it’s almost certainly a double cut file, so it worked, but a single cut file wouldn’t work on the pull.
http://www.facebook.com/profile.php?id=1595533387 Bob Scheu

Jimi Hendrix played thru a box called a UniVibe with similar intent. Originally an effort to mimic the sound of a rotating Lesley speaker setup, the Univibe used a photosensor and, I believe a rotating mirror for the variable. I don’t know if it had impact on other parameters beyond volume. As I recall, it was first played in public at Woodstock. EMP in Seattle has the prototype. Purchased at auction, it was not fully functional; fortunately a local wizard had the schematics and restored it to full functionality. There are legions of Hendrix “train-spotters” that can go on at length about such things. Anyone?
- http://twitter.com/smknghrtdesigns SmokingHeartDesigns
  
  Univibes were vibrato emulators, and vibrato has to do with pitch change. At high enough rates it sound similar to a tremolo. Usually a vibrato uses some kind of variable resistance to change the phase of the signal which would be the equivalent of making the sound waves “faster” or “slower” and affect the pitch. Tidbit: if you remove the dry signal from a phaser you get vibrato.