On 7/4/15 11:55 AM, Mike Magin wrote:
Somewhat new time-nut here (had one of the Samsung-branded Z3805s for a
few months as a house 10mhz ref, but it really got out of control when
I acquired a Wavecrest DTS, multiple frequency counters, an old Astron
1250a, a Lucent RFTG-u pair, etc.), thought I should finally de-lurk
since I can perhaps offer some useful opinion on this. Comments inline.
On Sat, Jul 04, 2015 at 06:13:06AM -0700, Jim Lux wrote:
I've got a project I'm working on to make a sophisticated sundial
with moving mirrors. I've got a batch of Arduinos that move the
mirrors to the appropriate places, given the current sun angle, etc.
I guess you are making a human-readable sundial,
Exactly... I've got an array of mirrors on az/el mounts (two servos
stacked) and the reflection from the mirrors on the wall forms the display.
I was thinking recently
about building a computerized mean-solar-noon tracker, just to see what
sort of accuracy I can get. Haven't decided between a cheap fisheye
camera behind a dark filter (welding lens?) versus a sort of slot-lens
(like a pinhole, but to tolerate the seasonal change in north-south
elevation) with a wide-range light sensor (CdS or a modern ambient light
sensor IC).
How accurate do you need to be..
two/four solar cells with a hole that projects an image of the sun on
the cells, and compare the outputs (classic sun sensor for a satellite)
spinning mirror and fixed solar cell, timing of pulse tells you where
the sun is
camera with a wide angle lens, and then do multi-pixel centroiding (0.1
pixel is easy)
camera sensor with a plate with tiny holes in it, with the spacing of
the holes slightly different than the pixels, so the "sun spots" have
slightly different coverages of each pixel.
I've got a beaglebone that runs some python code to calculate sun
angle based on time
[...]
Or are there libraries that make this more cookbook? (the little
"getting started with beaglebone" book talks about flask)
In a previous contract job, I did some work with Flask, it's pretty
nice, especially for the basic case of "make this subset of the URL
space be handled by this function".
I haven't set it up from scratch, but the Flask documentation seems pretty
good, and if you're already familiar with Python, I'd highly recommend it.
Well, I got it to do the beginner "click here and turn on/off the LED"
thing..
What I'd like, though, is to separate the "web serving" thread and the
"doing stuff thread". I suppose I can fire off a thread from the
webserver python.
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