My stupid pet trick,
David the Burger Inspector, is the result of two failed ideas.
My original idea was to make the burger a combo lock, with the LEDs as the sesame seeds on the top bun. Arrange the pieces in the right order, and the sesame seeds will light up!
After talking to Chris, Amy, and Ithai, we decided it would be difficult and ugly to do this. In order to get the current flowing to the top of the bun, we would need to have registration points (wire mesh) on both sides of each piece, conductive thread connecting each point, and a heavy piece of cardboard inside each piece to make sure the two points don’t touch.
So we thought about using an FSR and giving each piece of the burger a different weight, and instead we would have a little man connected to the burger, with an LED inside his stomach. If you made a veggie burger (tomatoes, pickles, lettuce), his stomach would light up green. If you made the perfect burger (no pickles), his stomach would light up yellow. If you packed too much on the burger (everything), his stomach would light up red because he has indigestion.
I made the different pieces and stuffed them with rice and cotton balls:
But I found it difficult to get an accurate reading. I would weigh each piece and map out the values to the LEDs, and then the next time I put the burger pieces on the FSR, I would get something completely different. Alex suggested that I put a plate with a quarter on top of the FSR so the pressure is evenly distributed. Chris thought it was because the burger was hitting a different area on the sensor every time, so he suggested putting felt in between the two plates to keep it more steady. Even then I still had trouble. Little things would screw up the results, like putting my fist down on the table, or dropping the meat patty instead of carefully laying it down. Tom said my problem is that I need to have four sensors with little rubber feet instead of one big sensor in the middle. I didn’t get a chance to try this out, because I only had one big FSR and the bookstore was out.
Chris and I decided that at this point, I should just shove all the weight in the pickle and have it max out the sensor. I dug up every coin I could find to weigh down the pickle, and turned the man into a burger inspector.
If a pickle is present, he flashes a red light, warning me not to eat this delicious looking burger.
If no pickle is present, a green light glows which means the burger is okay to eat.
Chris suggested a great idea for my final project. I’m going to make more pieces and use them to teach kids about nutrition, and also make a Processing sketch to display calories and other important nutritional data. I haven’t thought about it too much yet, but I’ll probably have a lunch box and the child must pack his own lunch. If he doesn’t meet the nutritional criteria, then the lunchbox won’t close and he can’t take it to school. Or I might build it cafeteria-style, with plastic trays, a buffet line, and lunch lady Doris.
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on Friday, October 16th, 2009 at 9:28 am and is filed under Physical Computing.
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