There’s been a bit of a lag in posts lately for a good reason. I just have to come up with it quick. Thinking…thinking…
Oh yeah, I’ve been busy. Really busy. There you go.
I tend to get sucked in to projects and disappear into the lab for months at a time. Ask around. Go on. It’s a vicious cycle, really. Because I’m always in the middle of one project or the other, this should come as no surprise. But this one…this is a project I’ve been working on for years now.
If you go back far enough you can find DARN. Slightly less far back is a post involving DARN and frequency analysis. Now I’m preparing for the next iteration. The biggest change is a surprise, but something that will make this version better than ever. The pressure, temperature, accelerometer, and gauss meter are already sussed, but the EMF/dynamic magnetic field /magnetic flux sensor is becoming quite troublesome. Ever try to filter and amplify something that’s between 1-200uV, in the low frequency range, and with a .6V DC component? It’s all fine and dandy until you replace the ideal op-amp model with the gritty real world.
Then things get really fun.
On the previous versions, I just modified this rather swell design to suit my needs:
http://www.zen22142.zen.co.uk/Circuits/Misc/emf.htm
But my inductors were always hand-wound and, frankly, horribly unappealing in terms of aesthetics. And because of their homemade nature, each varied wildly causing me to calibrate each sensor in software. While it worked for the last two models, I’m hoping for a bit more consistency this time around. And…well, I’m out of old ferrite antennas. Ehrm. As such, I decided to take the inductor out of the equation entirely and try rocking this little guy:
http://www.sparkfun.com/commerce/product_info.php?products_id=708
Which, as you might imagine, is proving quite the headache. Even with multiple gain/HP filtering stages, it’s getting a bit dicey. I suppose that’s why there’s a lack of schematics featuring them in an ‘EMF’ meter design. Nothing worth doing is ever easy.
Drat.
Back to work I go!
–Josh
Josh, one quick thing. You are my favorite geek of all time and I love you for that one. And yes, you do know me. But one thing, I call my lab (a.k.a. my bedroom.) my bat-cave. I will be there for weeks on end non-stop. As to my knowledge, you are quite the genius. It comes to my attention that some thinsg are a little under my head yet, you don’t have to elaborate your works. I’m trying to work on a project that in a later time I will discuss with you. Although, something else comes to my attention. If I were a decade older of age I would ask you out for coffee. Oh joy, more caffine. I drink a lot of it. Well, it looks like you have your work cut out for you. And maybe, in the future where I would be working with you as a fellow paranormal investigater, I’d use one of your contraptions.