## Day 2: Wednesday, 7/6

by on Jul.06, 2011, under Week 1

Today we finished the TETRIX bridges; Sarah and Briyana’s bridge was the second longest and most solid, Dean and Jess’ was the third longest and second most solid, and Lawrence and my bridge was the longest, but least solid, by far.  The first two bridges barely deflected since they were the same basic construction (the metal u-sheets connected together).  The final bridge was more outside of the box thinking: it used the battery charge cable to act as a flexible bridge.  However, that ended up failing as the weights caused the cable to sag and the outer edges to collapse inwards.   We attempted to make a SAM animation of the bridges deflecting under the weight, however the first two bridges did not deflect enough and the third deflected too much too quickly.

The rest of the day we worked on various connection types: figuring out the best ways to connect LEGOs, TETRIX, and everyday objects.  We learned that LEGO axles and TETRIX shafts are the same diameter (except of course the LEGO axle is not circular: it’s + shaped), that the blue lego connectors can be pressure fit into TETRIX wheels, and that pencils and screwdrivers fit perfectly into the large TETRIX holes.  Using this knowledge, we started the second exercise: object holding.  Drawing three numbers from a bag determined what objects the constructed robot would need to be held.  They had to have omni wheels, and had to be able to be pushed across the room without spilling their contents.  Jess and I’s had to hold three different sized screwdrivers, a pencil, sharpie, and pen, and a calculator.  Lawrence and Briyana’s had to hold a full cup of water, a CD, and another robot.  Dean and Sarah’s had to hold spare change, a Nintendo 64 game, and a huge wrench that could spin free.

Daily Thoughts:

Dean: Testing bridges/SAM: SAM failed, didn’t really see point of it.  Holding devices: good way to learn about TETRIX connections and useful knowledge for later.  Thought of Tank idea.

Lawrence: The bridge was so much fun because we had an outrageous idea but it didn’t work that well. It still gave us enjoyment though. Later in the 2nd day finding connections for Lego’s to Tetrix was very useful for our remaining projects. The water holder I built was mainly out of Lego’s and it was really fascinating. I found a way to connect it securely and the project was mainly a success besides the omni wheels made the ride too bumpy for the cup of water. I also learned that day that you should always plan out things before you do them because I messed up the crane on my robot many times and it became a catastrophe but even though it got frustrating I finally got it right. Hahahaha.

Jess: Going into day two, I was looking forward to finishing building my bridge and seeing if we could win the challenge. It became pretty evident rather quickly that we didn’t have a chance. Then building the holding robots was pretty awful, since my group had to build one that would hold a pen, a pencil, and a marker. Tetrix really wouldn’t cooperate with that objective. I was pretty happy with Tetrix’s ability to hold the calculator, though.

Briyana: I struggled with building a CD drive that actually held the CD…I over thought the whole process. After I simplified my thought process I ended up using rubber bands.

Sarah: Connecting TETRIX and LEGO pieces requires a lot of jamming.

Nicolas: The SAM animation of the bridge testing was incredibly awful.  I was hoping you could really see the deflection, but the bridges barely deflected and the camera setup was both awkward and not fast enough (taking a picture every .1 seconds did not allow showing the minute deflection)

1. The easy part was putting the pieces into one another. The hard part was making them stay. The wheels were somewhat harder to find the correct pieces for to have them be long enough for the motor but not be wobbling.

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