So on the last day, we set up the heat press inside the vacuum chamber and found some LDPE, HDPE, and PTFE.
PTFE, or teflon, is the coat of plastic that posseses anti-reflective (AR) properties.* HDPE (high density polyethlyene) gives the AR coat/window stability in the vacuum. And LDPE (low density polyethlyene) functions as the "adhesive" for the HDPE and PTFE.
(*see the first post for more details about AR windows and this project)
LDPE melts at about 120 degrees C, while HDPE at 130 and PTFE at 330. So we let the heat press warm to about 125 degrees C. Everything worked out pretty well, except for one thing: in the spirit of being an amateurish, undergraduate intern, I had reversed the order of LDPE ad HDPE. So instead of getting a nice HDPE-PTFE-HDPE sandwhich, the LDPE just melted onto the heat plate since I had placed the sheets as the outermost layer. But the good thing is that the LDPE melted, and the other two plastics didn't. So I guess we'll look more into this in the Fall.
It's pretty remarkable how it took half a summer to reach this point. I've definitely learned a lot. I'm interested in astrophysical instrumentation so this is pretty much the summer work experience I was looking for: tinkering with electronics, burning myself, and occasionally blowing things up.
I would like to thank Dr. Ross Williamson for being my mentor, and the Columbia WEP program for making this summer possible.
I am looking forward to continuing the next phase of this project in the Fall Semester.
Wednesday, July 11, 2012
Monday, July 9, 2012
Week 7
The Fourth of July was last week, so Happy Birthday America. It also happened to fall on a Wednesday, so it was nice to split the work week in half. I got to view the fireworks from the uncrowded fire escape of a friend's apartment, which was nice.
For the most part I soldered wires to all three leads of all 32 LM35s. To calibrate them, I found a copper disk and drilled holes around the edge and screwed them in.
The soldering was very, very tedious. The +5V and GND leads for 16 of them were to be daisy-chained, so that required soldering two wires onto one tiny leg for each sensor, which took some time. But with the liquid "flux" solution it became much easier.
I also played around with the multiplexers on a breadboard again, and since I had tested one of chips last week, this was also pretty straightforward.
The only really challenging/aggravating task was manipulating labview to try to get the multiplexers to read out the MUX chips. I had to do some reviewing on binary logic to get that to work, and it still doesn't work perfectly. I hope to learn Python at some point so I wouldn't have to deal with Labview.
Anyway, this is a short post since today is my last day in the lab, so we're going to heat both plates in the blue monster that is the vacuum chamber, and hopefully blow something up. I'm also a little tired from the weekend.
Oh, right. I can't forget. The Rockaway surf report for the past weekend.
Saturday was very small, but the waves were picking up to the knee high range towards the evening near the rock jetties on 90th street. I accidentally dropped in on one of the longboarding locals, and he wasn't too happy. I was genuinely apologetic, but he was still pissed. My bad, dude.
Sunday had more wind and had a few inconsistent sets roll in. But on the plus side, it was a beautiful day, and I got my friend to stand up on a surfboard, so that's a success in itself!
For the most part I soldered wires to all three leads of all 32 LM35s. To calibrate them, I found a copper disk and drilled holes around the edge and screwed them in.
The soldering was very, very tedious. The +5V and GND leads for 16 of them were to be daisy-chained, so that required soldering two wires onto one tiny leg for each sensor, which took some time. But with the liquid "flux" solution it became much easier.
I also played around with the multiplexers on a breadboard again, and since I had tested one of chips last week, this was also pretty straightforward.
The only really challenging/aggravating task was manipulating labview to try to get the multiplexers to read out the MUX chips. I had to do some reviewing on binary logic to get that to work, and it still doesn't work perfectly. I hope to learn Python at some point so I wouldn't have to deal with Labview.
Anyway, this is a short post since today is my last day in the lab, so we're going to heat both plates in the blue monster that is the vacuum chamber, and hopefully blow something up. I'm also a little tired from the weekend.
Oh, right. I can't forget. The Rockaway surf report for the past weekend.
Saturday was very small, but the waves were picking up to the knee high range towards the evening near the rock jetties on 90th street. I accidentally dropped in on one of the longboarding locals, and he wasn't too happy. I was genuinely apologetic, but he was still pissed. My bad, dude.
Sunday had more wind and had a few inconsistent sets roll in. But on the plus side, it was a beautiful day, and I got my friend to stand up on a surfboard, so that's a success in itself!
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