A Maker Wedding

This post is a little late in coming, but this past March I married a wonderful and patient woman, Beth.  For our wedding we wanted to keep costs low and still make it very personalized, so we did all of the planning and made several custom pieces for our special day.  We planned color schemes, table settings, and the hall layout using InkScape - an open source SVG editor, and Beth made beautiful blue and black ribbon table squares for the centerpieces. I designed 3D printed candle holders, and custom ties for my groomsmen presents.

More details and fancy bits after the break.

Automatic Cat Feeder

It's 4am, and I'm sound asleep dreaming of robots when I'm startled awake by 10 lbs of hungry cat jumping on my face with a pleading "mew".  I get up, feed the cats, and unsuccessfully attempt to resume my slumber.  This scene repeated itself every day for only a couple weeks before I decided I needed an automatic cat feeder to maintain my sanity.

The feeder needed to only handle dry food, be able to ration food quantity so that the cats wouldn't get fat, and it needed to have a lot of storage so that the cats wouldn't starve while my wife and I were traveling.  Similar off-the-shelf feeders cost upwards of $50, and I like a challenge, so I set out to build one myself.

Build details and more pictures after the break.

3D Printed UAT Shadow Sculpture

Last week I built this shadow sculpture inspired by the cover of the Pulitzer-prize winning book "Gödel, Escher, Bach: An Eternal Golden Braid" this is a 3D-printed form that casts three orthogonal shadows in the shapes of the letters UAT.    After I printed it, I used some blue LEDs and foam-core to build a little display platform for it.

Here is the Inventor part file: UATCube.ipt

The Guardian: Inexpensive AVR-based Cat Food Protection

Over 6 months ago we added two kittens (Duke and Ella) to our household, and we found out that our dog, Riley was eating their food.  To prevent this, I built the Guardian, an AVR-based protection system that humanely keeps Riley away from the cat food, but is not triggered by the cats themselves.

I wanted this setup to be cheap, so I decided to use an infrared "trip-wire" system.  On one side of the hallway is an always-on infrared emitter, and on the other side is an infrared receiver, an AVR ATmega8 microcontroller, and a buzzer.  The micocontroller continuously checks to see if the beam between the emitter and receiver has been broken - if it has, it sounds the alarm, which Riley hates, driving him away.  The microcontroller is programmed so that small, fast things (such as cat tails) do not trigger the alarm.  Also, the whole rig is place at Rileys shoulder height, which is much taller than the cats bodies.

This may not work for most dogs, as Riley is a pansy and afraid of loud noises, but here are the schematics, source code, and a rough bill of materials:

Schematics (Eagle, PNG)
Source Code
Bill of Materials

ArcAttack: Ride the Lightning

I've always been fascinated by Tesla Coils. The operating principle is so elegant - you set up one circuit (your power supply) that oscillates at some high frequency, and you set up another circuit that uses the earth to resonate with your power circuit. Energy is transferred and converted from current to voltage, and the end result is man-made lightning - an incredible display of light and sound.

Newer versions of the Tesla coil allow the control of the resonant frequency.  Have you ever noticed the sound that a flourescent light makes?  That kind of "buzz" ? You're hearing the frequency of the power that is coming into your house (around 60Hz).  When you control the resonant frequency of the Tesla, you control the tone that it generates, and thus the Singing Tesla Coil is born.  This is not lightning set to music - the sound is generated by the spark itself.

The band ArcAttack has integrated a pair of singing Tesla coils into their repertoire, with epic results:

Spinning RGB LED Ball

Unlike it’s predecessor this one has three axes. It was very challenging to build, with a total of 9 slip-contacts, not including the motors. I made it from scrap I had laying around and it took about a week to build. I use standard DC-motors controlled with pulse width modulation, the LEDs are controlled with a modified bike light with adjustable frequency.

More pictures via HackedGadgets

Delta Robots

Adept's new Quattro arms are hard to beat:



So you might want to build your own:

A Real Turing Machine

Mike Davey presents his hand-built Turing Machine.  The machine uses a Parallax Propeller chip for mechanical control, but actual computation is executed using the tape reel. 

My goal in building this project was to create a machine that embodied the classic look and feel of the machine presented in Turing’s paper. I wanted to build a machine that would be immediately recognizable as a Turing machine to someone familiar with Turing's work.
Although this Turing machine is controlled by a Parallax Propeller microcontroller, its operation while running is based only on a set of state transformations loaded from an SD card and what is written to and read from the tape. While it may seem as if the tape is merely the input and output of the machine, it is not! Nor is the tape just the memory of the machine. In a way the tape is the computer. As the symbols on the tape are manipulated by simple rules, the computing happens. The output is really more of an artifact of the machine using the tape as the computer.

You can get more details about the construction of the machine at Mike's Site.

Kohctpyktop: A logic design challenge

Feeling nostalgic for those frantic days in the digital design lab? Wish there were perhaps a game that put you in the place of an engineer, trying to design new ICs to meet the goals of some unspecified organization? Want to get your SI on? No idea what I am talking about?
Well then, let me introduce you to Kohctpyktop: engineer of the people, by Zachtronics Industries. It's the first game I've ever seen where you have to design integrated circuits as a challenge, sort of like pipe dream for electrical engineers.

Kohctpyktop via Make

Mechanical Wooden Clocks

Clayton Boyer designs sweet wooden clocks, and he also sells plans so that you can build your own.