Magnets!

July 27th, 2010

First test of my coil this afternoon over at the USGS! Not without some troubles, but still its rewarding to see some kind of result for a solid few weeks of work. I've learned alot about basic circuitry and power amplification through this, if nothing else. I started the project with a couple fundamental misunderstandings of what an op-amp and transistor would / could / will do to my signal. Since the last blog though, I now have a coil... it runs between .5 and 2.5 volts with a resistance of about 2.5 ohms -- you can do this math, that's about an Amp of current at its peak. There's challenges ahead to keep me busy:

-Reducing noise in my created signal (designing a better circuit with shorter wires and more twisted pairs to cut down on self-induced pick-ups)

-Need to take it to the field and characterize responses given that my sensor is buried about a foot deep. What happens when we don't know exactly how deep, or even exactly where its buried!?

- Want to be able to automatically step through different frequencies. I've designed it to be variable by hand (turn a screw on the Pot out front), but we want to be able to automate changing through a series of known frequencies.

On the other side of things, still working on getting traces of a co-seismic signal. That is, when the ground is actually shaking, it should show a trace on our magnetic sensors ( think of it as a pseudo-seismometer ). There doesn't seem to be a strong correlation, "strong" being relative to the daily noise from other things such as our BART muni-system, so its still a little frustrating. We haven't given up hope though, we just need to know exactly what to look for. In this whole process I since learned the ins and outs of shell scripting to specify exactly which seismic events SOD should download, automating that process to speed up the search.

I'm starting to feel the pressure as a deadline is approaching. I know some of you are even closer to a finale, so I can understand the excitement / anxiousness going around. Despite things picking up here though, I'm excited to say I'm taking a couple days off at the end of this week to get some backpacking in with the girlfriend. First couple days off for me since March! (weekends and the IRIS orientation week not-included, though that was pretty fun)