My mother always told me not to rest my arms on the table while eating. Although I never saw the merits of such a behavior, I did not object to her mandate and have been careful about where I placed my arms while sitting at the table ever since. Nowadays, table manners seem to have lost their significance. Yet it is never too late to learn some dining etiquette! For my Second Intro to IM assignment, I made an electrical circuit that identifies improper table manners. If only arm rests on the table, a yellow LED lights up, warning the user of her potential transgression. If, however, both arms rest on the table, both red and yellow LED’s start flashing. This is a clear signal to the user to move his arms off the table.
The mechanism makes use of digital input and output to the microcontroller. Each arm and a piece of conductive fabric taped to the table mat serve as a switch and hence constitute digital input. If only one switch is closed, only the yellow LED light turns on (as specified in the recipe for the microcontroller’s behavior that I wrote in Arduino). If both switches are closed, all three LED’s that I connected to the circuit start flashing.
I encountered several design problems in the process of making the circuit. Firstly, I was not sure how to create a part of the switch taped to the arm. Luis helped me out with a brilliant idea; he suggested I use a Band-Aid, cut a hole through it, put some conductive fabric on one side of it and tape a wire on the Band-Aid so that it touches the fabric. When I pressed the Band-Aids against the conductive fabric on the table mat the switches worked perfectly. However, when I tried taping the Band-Aids on my arms I could not close the switches without considerable hassle. The project thus has a lot of room for improvement, but even now I see in it a potential to teach and reinforce valuable table manners.
