[Mon Apr 9] Lantern Project Second Day

Note: when I was editing my blogs, I pressed "undo" on this page, which leads me to the my entry on April 12. Then I am not sure what I did, but the content in this blog was replaced by my April 12 blog... That was really frustrating... Anyways, I rewrote this entry based on my memory of what I wrote since I just edited it... Therefore, it is not as detailed and comprehensive. Hope you can understand.

Essie and I decided to work on the battery case today. Since Essie is much better at using Inkscape and mapping out the design, and it is hard for two people to draw together, we decided to split our work and I worked on circuits instead.

I pulled out the materials we picked out from last class. I first learned how to connect a switch in a circuit:

As shown above, the switch can be up (at the position in the picture) or down. If the switch is up, then A and B are connected in the circuit; if the switch is down, then B and C are connected in the circuit. For the purpose of our design, if we just have wires extending from one of the outside points (A or C) and from the middle point (B), we would be able to connect and disconnect the circuit by putting the switch up and down. 

I started with putting the yellow LED with the 270 Ohms resistor all in the same row, connected to a switch in a different row because I couldn't fit them all in the same row. I tested with the two batteries we picked out, but it didn't light up. After examining everything, I asked Oscar for help. Apparently I am not supposed to put the two LEDs' legs in the same row because then I'd be shorting the LED and there wouldn't be a voltage difference across the LED. I am pretty sure we learned that when we dealt with circuits earlier in the semester but I completely forgot. It is not going to be that important in our design though because we will build the circuit directly on acrylic.

Anyways, I fixed the layout of the circuit but it still didn't work. Oscar gave me a battery tester to test whether the batteries were charged. One of them was a little weak so I changed it. Then it worked fine.

I put in the green LED and here is the final circuit:

The white and blue wire coming out from the board was connected to the positive and negative end of the batteries.

Then I took some time to measure the thickness of the wires and legs of switches, LEDs and resistors with a calibre. They all turned out to be slightly different, but I don't know how much a difference it is going to make since they are all so small.

I showed the circuit to Essie then joined her in her battery case design. That involved drawing, cutting, assembling, getting angry, cooling down, rethinking and redrawing again. Although having a company definitely felt better than doing this alone...

By the end of the class, we had a not so fit battery case. I did not get a picture of it but it looked pretty similar to a more advanced version later in the week.