Thursday, May 28, 2009

Prototype, Problems, and Final Class Crit

Not too many updates since the last one yet so much has happened.  To bring things up to speed I will use bullet style:
-Figured out how to read xpos serial data to control the speed of a motor through an encoder thanks to A Big Magnet but couldn't control the direction.  
-Lalya and I got some directional feedback but when I took it home to fine tune it, I burned out my Arduino and Motorshield. 
-After debugging the board and shield to make sure it really was fried (not sure how I did this but the important thing learned is you can never be careful enough!) ordered a new ATMega chip and Shield.
-When the shield got in and I put it together, met with Lalya and decided the best course of action for the crit is to have a prototype that just moves one of the cutlery.

So, then in one weekend I scrambled my butt off to get something that looked presentable.  Went to a local window tinting shop in Cranston and bought something called R20 which is a two-way mirror sheet.  Then built a quick little wooden table frame at the woodshop.  Cut a piece of plexi to fit the top and adhered the R20 to it.  Then I purchased a pack of high-powered magnets and inserted them into the cutlery.  I had to hand draw the ficudial ID's on the fork and knife because the video camera wouldn't recognize the small printed ones--they were too pixelated.  So then after renting a camera from media resources I set to calibrating the machine.  Basically the code is telling the motor that when it recognizes the knife a certain distance away, to move for a certain amount of time backwards and then forwards.  This means that the motor doesn't actually know where 'zero' is it only moves a certain amount backwards then forwards.  After building a shadow box around the table to make the two-way mirror work best, the prototype worked and was unveiled successfully at the critique.

The next part is working more on how to maximize the effectiveness of the components I already have and then to build a table that can move x and y positions.  This will be my potential summer project.

-Evan

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