Friday, November 19, 2010

Dome Chess Board

This is project is a work in progress.

Inspired by this chess board, I wanted to try making a dome shaped chess board. Thanks to my friend Fred, I was able to get my hands on an aluminum hemisphere and with his help I have been working on shaping and cleaning it up.
The top surface will be painted with magnetic primer before the chess board pattern is painted on. This way I can use standard magnetic chess pieces. Eventually I would like to make my own chess set with my 3D printer. More to come soon...

My MakerBot

This is my DIY 3D printer. It's comprises of a kit purchased from Makerbot Ind. I received the kit back in November of '09, but due to the holidays and work I wasn't able to get it assembled and working until April of 2010. Since then I have added several upgrades.

My first upgrade was more of an attempted upgrade. I tried to add a heated build platform. The build platform is what the part is printed on. Due to the nature of the plastic used (ABS) the prints have a tendency to warp as they are printed. A heated build platform significantly reduces warping in the print. My first heated build platform didn't work out due to epoxy failure.
The wedge shape is due to the epoxy around the screws holding the top ceramic plate to the wood base. After this failure I purchased a different heated platform kit. This went together with much more success.

The detail image show my solution to losing the small surface mount components during my attempt to solder them without tweezers and compromised fingertips (band-aids). Additional upgrades I've added include the new MK5 extruder and a filament spool so the Makerbot can auto-feed. I'll post pictures soon.

Einstein's Clock

This is a project I started during my junior year in college. Between classes and working it took about a year to complete.

Basic Concept:
I found that with every clock, no matter how abstract the face is, the hands always move in perfect circles. This inspired me to create Einstein's clock. The basic idea was to design and build a clock where the hands do NOT move in perfect circles.

How it Works:
The minute hand is attached to the bicycle chain which follows an irregular path created by the randomly placed cogs of varying size. Through the clever use of a low RPM motor and gear ratios, the minute hand makes one complete rotation every hour. The hour hand of this clock is simply the cog in the middle. The hour cog/wheel/hand thing has 24 teeth (one for every hour of the day) which ratchets over one tooth every time the minute hand goes past.

What Makes it Einstein's:
Good ol' Einstein threw us all for a loop when he showed through relativity that time may not move at a constant speed. Due to the irregular shape of this clock, the minute hand can be pointing in one direction (signifying one time) and then 5 minutes later be pointing in the same direction (signifying the same time). Also, along some parts of the clock the minute hand moves relatively quickly, while along other parts the minute hand seems to barely move at all. The combination of these two effects gives the illusion that time is not moving linearly, hence Einstein's Clock.

Pictures and Development:
As you can see in the images below, the general shape remained the same while the orientation and the back board changed. The board in the center picture was cut out from the board in the first picture. It broke and so I made the board in the third picture. You can click on the images to see larger pictures.

Materials and Construction:
The original board was a 24"x24" piece of 1/2" plywood. After breaking that, I used two pieces of 9/32" plywood glued together. I glued two boards together so that I could mount the 1/4" motor plate flush with the face. The cogs were cannibalized from various bicycles and mounted on aluminum hubs. The cogs are attached to the board using T-nuts and 1/4" stainless steel socket head cap screws with nylon spacers holding the cogs away from the board. The chains are just cheap bike chains (318 links for the perimeter and 50 links for the motor circuit) and the motor is a 1-1/3 RPM, 115VAC induction gear motor. I used an induction motor because the RPM is based on line frequency (generally constant at 60Hz) rather than line voltage (Which varies from 110V to 120V).

If you want to calculate it out here are the numbers:
1-1/3 RPM motor
10/25 gear reduction
10/318 gear reduction

That comes out to a little over one rotation per hour, but the motor is a little slow, so it comes out almost perfect in reality. Detail images of the gear reduction and of the spring tensioner below:


Thursday, November 18, 2010

Stop Motion Animation

This is a simple stop motion animation I did during my senior year in college as part of a digital design class. Sadly this is my only sample from that class which survived my hard drive crash. The animation was done using Photoshop.