Section I: Circuits, Tutorials, Instructions

How to use Test Equipment

Color Organs, no Arduino

Color organs, with Arduino

Getting sound from a microphone into Arduino is pretty easy. You do need to amplify it because the signal straight out of a microphone is too weak for Arduino.

Sparkfun makes a nice little product with a built-in amplifier. It has  fixed gain. You need to speak right into it. If you want to respond to music, you’d have to stick this right in front of the speaker.

Adafruit a similar product with adjustable gain.

To respond to different frequencies, you need to separate the incoming sound into how ever many ranges you want. Two or three is usually good: high range, midrange, and low range. Note that the amplifier and filters are completely independent of Arduino; you’d use them regardless of whether you are using an Arduino or driving the LEDs directly with a transistor.

Arduino is too slow to do in software, so you have to use hardware to make 3 different filters, and then feed the output of each filter into a separate Arduino analog input pin. Designing filters is an old and continuously evolving art. Fortunately there are some online tutorials that show how to do this, although some are not well documented and are termpermental, meaning they might work in one particular setup but then not another. My students have had very mixed results.

This last one is from Jeremy Blum, who usually does excellent work. I’ve not tried his yet because I don’t have patience for videos.

The key words to Google on are “color organ” and “sound to light” .

Color organs, unsorted

Some might be duplicates of those above


Miscellaneous Circuits

Tutorials, except Arduino

Section II: Components

Local Stores

  • Al lasher’s (Berkeley, very knowledgeable staff )
  • Electronics Plus (San Raphael, very knowledgeable staff )
  • Arch: Art supply store near Potrero Hill
  • Center Hardware: Hardware store near Potrero Hill
  • Tap Plastics: All sorts of plastics, resins, and mold making supplies and tools. Laser cutting service.

Almost local

  • Jameco. Belmont. Surface mail usually arrives the next day. Very friendly and helpful staff. If you need an order in a hurry, call them after you place the order and ask them if they can ship it the same day. A human always answers the phone. General electronic, Arduino, etc.
  • Electronics Plus. San Rafael.
  • Oddwires. Contra Costa county. Surface mail arrives within a day or two. Small company, will often stock what we ask for. Orders placed by 4pm usually ship the same day; email or call to confirm. General electronics, Arduino. Stock many Adafruit items that we use often: Motor shields, servo shields, WAVE shields, etc.

Surplus: great prices, usually new or almost new, might not always have the same parts

Audio Parts

Home Automation (Sometimes useful for sensor and control modules)

Section III: Unsorted and misc

Local places to work on projects and get informal help

  • Open hack night every Wednesday at Tech Liminal in Oakland
  • Techshop: Giant workshop with wood and metal working tools, 3D printers, laser cutters, etc. etc. Gym-like membership.
  • Hacker spaces often welcome non-members to bring projects or questions

Websites with excellent Arduino parts, tutorials, examples


Other lists of links


  • Sensor workshop at ITP, including long list of different sensors
  • Sensorland

General Industrial Supplies

People, Projects, and Groups we admire

Physical Computing

Materials and Products

Motors, Mechanisms, and Animatronics

Mechanical and  Mechanism Construction

  • How to build simple mechanisms out of cardboard and wood pamphlet by Paul Spooner
  • Animated linkage mechanisms
  • Library of kinematic models for design

Arduino Project Examples

How to protect electronics in rain, dust, etc.

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