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The latest addition to our Weekend Projects series is an Optical Tremolo Box. Inspired by Charles Platt’s article about online DIY guitar stomp-box communities (MAKE Volume 15, page 82, “Stomp Box Basics: Tremolo and Fuzz”), MAKE Technical Editor Sean Ragan took up the challenge of building this project. He used a cadmium sulfide photoresistor as the light sensor — a component we have used in previous Weekend Projects (see Light Theremin). This component, in combination with the flex light (or sunlight) and custom-designed “sweep disks,” provide you with the ability to create a wide range of tremolo. Also as our first project box build, Sean set the bar high for both design and function. Watch the video below for some clever tricks on fitting components. And when you build the Optical Tremolo Box, be sure to send us pictures and an audio sample of your build!

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Nick Normal

I’m an artist & maker. A lifelong biblioholic, and advocate for all-things geekathon. Home is Long Island City, Queens, which I consider the greatest place on Earth. 5-year former Resident of Flux Factory, co-organizer for World Maker Faire (NYC), and blogger all over the net. Howdy!


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Comments

  1. Joey Mancuso says:

    Can I have Jillian’s phone number?

  2. chuck says:

    Three words- O…M…G! I know what I’m doing tomorrow.

    1. Nick Normal says:

      +1! Keep me posted on your build, whether it’s our spec or your customized box (great idea for CD spindle blanks btw).

  3. chuck says:

    OK I’ve been doing some ‘mental prototyping’ and I came up with an idea- What if you used the clear end discs that come in a spindle of CDR/DVDR media and use the spindle hub from a dead disk drive to hold it? It would be a bigger footprint but the disks would be sturdier and the connection to the hub would be more reliable. Also with a bigger disk you could use two photoresistors and two light sources and seperate through paths to sync two seperate instrument sources with the same tremolo effect/rate. Also maybe a PWM control for better speed control. Maybe even a 555 dimmer so the light source slowly fades in and out. With careful adjustment of the motor speed and the LED fader rate cycle you could get some cool sympathetic harmonic craziness, added rythmic effects, etc. I’m really fired up on this one as my latest noise machine needs a little something extra. Thanks for the post!

    1. chuck says:

      Went yard saling today to find a discman to cannibalize and found one on the first stop. That’s a good sign- off to hack!

  4. smokin' charlie says:

    I might take a crack at this but I am going to try it with hall effect sensor and try and use different strengths of magnets in various patterns on the ‘disc’. I let you know when I get frustrated with that idea.

    1. Nick Normal says:

      Haha – sounds good Charlie. Keep us posted!

  5. Hank Curmudgeon says:

    My idea to modify this great idea would be as follows:

    1. Buy one (or more) of these and substitute it for the RadioShack motor: http://www.ebay.com/itm/Plastic-Tray-Holder-CD-DVD-Player-Micro-Motor-DC-3V-/251129163302?pt=LH_DefaultDomain_0&hash=item3a7876ee26

    2. Mount the LED at the end of a narrow brass tube so as to constrain the LED’s output to a narrow point. Mount this modified LED and the photocell ABOVE the plane of the disk with the two mounted at a 45° angle to each other.

    3. Take a CD or DVD paint your pattern onto it using flat black paint.

    4. Snap the disk onto the DVD mount on the motor, adjust the LED assembly so the light of the LED bounces off the reflective disk surface into the photocell, and let it spin.

    Ideas:
    - You could also cover the CD/DVD disc with crinkled aluminum foil for a totally random effect.

    - Mount the LED/photocell assembly on something similar to a tonearm like a miniature record player so you can adjust its position from center of the disc to the outer edge.

    - Cover a totally flat black disk with random patterns of narrow strips of prismatic reflective tape and use a bank of LEDs and a bank of photocells.

    1. Nick Normal says:

      hi Hank, Very extensive pre-build notes. Keep me posted on your build, I’m especially interested to see its physical build & size, and am also curious about the LED-bounce effect. That is a good part/find.

  6. [...] the piece Build a Custom Tremolo Effects Box, Chuck remarks: OK I’ve been doing some ‘mental prototyping’ and I came up with an idea- [...]

  7. Chris J. says:

    I had the same thought about the CD/DVD and PWM. I used the motor from a dead DVD player. I’m planning on using a cricut to cut the patterns in black vinyl and stick to the CDs. In version 2, I was thinking of adding a pedal to replace the speed knob and adjust on the fly while playing guitar.

    1. Nick Normal says:

      hi Chris, Awesome! Also keep me posted on your build. Thanks.

      1. Chris J. says:

        Build completed. The DVD drive spins too fast at the slowest setting so I need to revisit and add additional resistance or make the clear space father apart on the disc. Since the flashlight listed in the article is hard to find, I managed to find a similar one at Five Below for $3.50. It’s a larger diameter so the grommet won’t fit but the flash light works fine.

        Ver. 2 add PWM with a ATTiny85 & voltage reg so I can use a standard 9v wall wart.

  8. Nick says:

    Very cool! If I may suggest, if you make another music-related video, please demonstrate what the device does a bit more. I’m not a musician, I’ve only a vague idea what tremolo effect sounds like, and the video barely shows the results.

    1. Nick Normal says:

      hi Nick (another Nick!), Thanks for your note. Be sure to watch the blog, in the future I’ll talk a bit more about tremolo and various ways it manifests in instruments and even the human voice. Per your comment maybe I’ll try and show this device a little better too. Thanks for reading!

  9. John says:

    The link to the guide seems to be down. As a matter of fact, the links to ALL the weekend project pages seem to be down.

    1. Nick Normal says:

      Hi John – are the links still down for you? Everything is working fine for me.

      1. John says:

        Hi, Nick. Yeah, everything sorted itself out after that. Now I’ve got it all assembled but can’t make it work. Disassemble and try again, I reckon.

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