Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater
Wed, 30 Nov 2011
Things have not all been quiet on the Air Data Instrument front, although I haven't mentioned any of my progress here. Well, I change that now!
It's not done yet. But it's getting much closer.
I decided a few months back that I wanted to come up with a printed circuit board of my own, to make a much more compact version of the ADI. The whole "stick a bunch of breakout boards together" method is fine, but it's kind of bulky, and suffers from some pretty obvious weaknesses when it comes time to package it all up.
I've finally (I hope) come up with a schematic and a PCB design that I think will work. I've ordered all the parts I need to finish a couple of ADI boards (so I have spares for when I release the magic smoke -- I have no plans to offer anything but documents to anyone else). Next step is, once the parts arrive, to print out a copy of this board at life size and place all the parts to see what interferes, what doesn't line up, etc.
Then, if it all looks lovely, I can send the PCB design off to be fabbed, and if it comes back functional, I can confidently publish it as being finished, which would elicit a huge "Woot!" from me.
Of course, that leaves the whole "putting a case around it" problem, but that's an issue for a different day. For now, I'm content to say, "Oooh, pretty PCB."
Posted at 08:56 permanent link category: /gadgets
I've spent some time considering how to scan negatives. I have a bunch of old 35mm negatives, but much more importantly, I'm generating new 5x7 negatives. I have access to a scanner, but it's at work, and sometimes I really want to see how things turned out sooner than that.
So, I've explored various ways of "scanning" negatives with what I have on hand. And what I always have on hand is a digital camera of some variety. The problem is lighting the negative. I've got a piece of white plexiglas I can use at home, and I eventually broke down and bought a very small light table a while back, so I'm pretty well set.
However, over Thanksgiving, I was at my parents' house, and I was not well set. We were going through old boxes of photos, and found some 120 size negatives of my grandfather that we wanted to see properly. I had a camera, but I didn't have any of my diffusing materials.
It only took a few minutes to come up with what I thought was a particularly good use of improvised materials: plastic bags. We located a smooth, white plastic bag, cut it up into a single layer, and taped it to the window (it was still daytime). Then we taped the negative on top of that (careful to apply tape to the smooth side of the film, not the emulsion side). I set my G11 to "macro" mode (mostly for the decreased focal distance), and took a few pictures. I had my netbook with me, which has a copy of The GIMP on it, and used that to invert the image, and adjust the levels and curves to come up with a nice-looking photo:
Et voila, there you have it! A pretty decent reproduction of a negative from 1956, using just a digital camera and a white plastic bag. Not bad, if I do say so myself.
Posted at 08:36 permanent link category: /photography
Categories: all aviation Building a Biplane bicycle gadgets misc motorcycle theater