TTL serial doesn't have a formal definition, but as I'm accustomed to seeing the term used it is structured in the same manner as "regular" RS-232 with mark low and space high (but at TTL levels), and may be received thus by some chipsets that aren't as strict as the standard requires with regards to the undefined zone.
Normal drivers, e.g., the MAX232 and similar, are inverting and flip the UART-side signal (mark high / space low).
-- Rich Webb Norfolk, VA
On a sunny day (Mon, 14 May 2012 13:57:03 -0700) it happened Don Y wrote in :
I think you could PLL an oscillator the teh 1 S flashing LED on the board.
It occurred to me that GPS accuracy is given here at about +/-10 meters. Seems to be the case for altitude too :-) That is a simple way to look at it.
On a sunny day (Mon, 14 May 2012 13:55:03 -0700) it happened snipped-for-privacy@radagast.org (Dave Platt) wrote in :
Don't we have bots for that?
As I unserstand it the Kursk was probably sunk by a hydrogen peroxide and alhohol fueled torpedo which was started accidentally then stopped, but not made safe (if such a thing is possible after starting the engine - failure modes include fuel lines corroding)
A similar incident sunk a Brittish sub, but it was near the surface and all hands escaped.
-- ?? 100% natural --- Posted via news://freenews.netfront.net/ - Complaints to news@netfront.net
The time server software effectively implements a PLL. Cascading another would probably make matters worse (?)
By "given", do you mean "at this location, the GPS *system* can not provide better accuracy REGARDLESS OF RECEIVING EQUIPMENT than 10m"? Where did you get this figure?
I think fixed offsets (that vary very slowly over time and location) are relatively easy to tolerate. OTOH, if it bounces around "randomly" it's hard to extract meaningful data (without computational assistance).
"Am I *here*? No... wait... or **here**??"
Yes and no. They have full gyros and other inertial sensors. They are initialized just before launch, and later verify before suborbital peak with various astronomical fixes in addition to some earth and sun observations.
?-)
On a sunny day (Tue, 15 May 2012 13:52:39 -0700) it happened Don Y wrote in :
I dunno that software, but I think the detection of 4800 Bd RS232 is uncertain (interrupt latency etc). To use the LED signal would make a good sampler in a ramp for a PLL running at a much higher frequency than 1Hz. Loop can be really slow. Hey I fixed a stupid error I made in the soft, I parsed the time field as a float, that worked fine until this morning 9 o'clock, "09MM...." removed the leading zero and showed hours x 10.. And that also for some other fields. :-) Poor guy who uses it to send a drone.... LOL
Data sheet for this GPS module:
Specification: General Chipset SiRF Star Frequency L1, 1575.42 MHz C/A code 1.023 MHz chip rate Channels 20 channel all-in-view tracking Sensitivity -159 dBm Accuracy Position 10 meters, 2D RMS 5 meters, 2D RMS, WAAS enabled Velocity 0.1 m/s Time 1us synchronized to GPS time Datum Default WGS-84
I have not looked up what 'WAAS' is, so from that I get the 10 meters. I think I need no better.
I started on the waypoints implementation, and found some great sites (Dr math):
and the FCC distance calculator,
and now wrote a waypoint and course (heading) routine.
1024 waypoints should be enough....Like I said, this is good for years of fun. The math is nice too.
PS:
I have read that GPS can be accurate to the mm. The way they do that is use differential GPS to get within one wavelength (of the 1.5 GHz, makes about 19 cm) , and then do a phase compare at that frequency.
Sounds cool, maybe for J.Larkin who has all that RF test equipment.
Years ago I was joking at April 1 about a GPS mouse....
Google NTP, PTP, "time server", etc.
o'clock,
Ah, OK.
WAAS is (IIRC) only applicable in North America (I had the impression you were tight-pondian?)
Essentially, it's a correction factor that fixed (i.e., positions known to the nearest RCH :> ) *ground* stations compute based on instantaneous observations of actual GPS satellite data and "feed back" into the system to tweek the underlying accuracy. I think WAAS can result in 10 *ft* accuracy (maybe better?)
I designed a (maritime) autopilot (based on LORAN-C, though) in the late 70's that did this same sort of thing. You learn lots of little details about the simplifications you carry around in your head regarding signal propagation, earth geometry, etc.
I recall Knuth commenting in one of the TeX books that once you start doing typography (designing typefaces), its hard to look at "letters" (glyphs) thereafter without silently observing the ratio of descenders, the placement of serifs, etc.
On a sunny day (Wed, 16 May 2012 12:42:16 -0700) it happened Don Y wrote in :
Nice! I am still learning though.
That is true, I have written subtitle software, did translations too, and had a lot to do with fonts, An other field I have learned a bit about... Very personal perceptions for different people for different fonts, I prefer arial.... :-)
What I found most enlightening is how utterly *wrong* the prevailing "newbie" ideas towards the numbers and types of "fonts" (ick) in a document (along with *how* they are selected), a seeming giddiness towards "justified" alignment, etc.
E.g., how ragged right alignment is easier to read, how san serif typefaces are *hard* to read, the advantages of fully hinted kerning, etc. It's as if people discover themselves unconstrained by "conventional" typesetting consequential to "old" technologies and (somehow) think this new freedom lets them do things *better*!
"Um, there was a *reason* The Olde Way was The Way It Was. Understand that before getting 'artsy-fartsy' preparing documents that *hurt* the eyes!"
E.g., even something as archaic as tails on 6 & 9 (I prefer them on 6's but abhor them on 9's! This seems very counterintuitive - shouldn't they be identical glyphs differing only by rotation??)
I believe it's much simpler. So many users taking the defaults in MS Word that it becomes a de facto "standard." Witness the poor souls who actually claim to prefer Arial.
Let them use LaTeX!
On 6? 5 or 7, perhaps. Regardless, even the choice of lining versus hanging figures should be based on use, e.g., tables or body text.
-- Rich Webb Norfolk, VA
On a sunny day (Wed, 16 May 2012 12:42:16 -0700) it happened Don Y wrote in :
PS I ordered one of these: ebay item 150801522064 for 19$45 If you look close you see that is a board with BMP085_DataSheet_Rev.1.0_01July2008.pdf air pressure and temperature sensor, and HMC5883L_3-Axis_Digital_Compass_IC.pdf what it says, 1 degree resolution.
So that one is everything in one, programming for the Bosch pressure sensor is something else, but I also found example C code on the web.
After that I can work on the airframe and enjun. I want the liquid air/ oxygen as oxidizer, I want SPACE.
:-)
And why go for a toy?
Years of fun! :-)
On a sunny day (Thu, 17 May 2012 10:47:46 -0700) it happened Don Y wrote in :
It is not so critical, but identical would look better perhaps. The biggest issue with subtitle fonts -conflict- was that some use narrow font and I do not. The other issue is the 'l' that looks like a '1' in some fonts lI1 dunno how it shows over there Somebody suggested Teresias (font) and I actually bought it and did several DVD subtitles with it. It is supposed to be the best readable font... But I don't like it, it looks ugly, but the 'l' was very different. So I am back to arial for DVD subs....
That could be! I just don't think many people actually
*look* at their "finished (text) product". Heck, few even PROOFREAD the things!!And, people seem to think the justified text "looks cleaner" (more professional?) than ragged alignment. And, since it obviously (must?) take more "CPU cycles" to figure out how to insert all that whitespace to flesh out the line width, it *must* be better, right??
Too early in the morning! I was describing
7 segment digits (I thought I had typed that but obviously I only *thought* it! :< ).E.g., I find a (SEVEN SEGMENT :> ) 6 composed of five segments to look "incomplete". The top segment (commonly called 'a') is missing and that absence is very noticeable (to me). It
*wants* (IMO) that sixth segment!By contrast, a 9 composed of five segments ('d' missing, in this case) looks perfectly normal! And, adding the sixth segment makes it look "wrong". :-/
As a symmetry nut, I find this (personal) inconsistency disturbing. The "norm" seems to be "add them BOTH" or "omit them BOTH".
Similarly, we tend to think of M and W as flipped images of each other. Yet, if you actually design the two glyphs with that symmetry, at least one of them (often) "looks wrong". :-/
Yup. A *huge* mistake IMO when it comes to how "longs" are indicated in C (i.e., ALWAYS use an uppercase L!)
Dunno. I've never produced a DVD *with* subtitles so have never considered the issues involved. I.e., I had probably assumed the text was generated in the DVD decoder itself -- much like closed captioning in a TV.
But, thinking about it now, it is probably a separate video stream that is superimposed on the main stream? If so, can *any* image be thusly superimposed? E.g., imagine a "decorative font" where the symbols don't resemble conventional glyphs but, rather, "little pictures"!
OTOH, I *view* most DVD's with subtitles displayed. It seems to increase comprehension -- esp on films with foreign accents or lots of action/noise (though that may all play in with my visual vs. auditory processing preferences)
something else,
I've been more interested in something that would provide
*personal* propulsion. Something between an inside-out TreadWay (sp?), monocycle, RIOTwheel, motorized unicycle, motorized *skate*/mono-board and ????.I.e., nothing "boring" and something in which more unconventional controls can be applied. Yeah, you could argue it is practical in that it provides real transportation. But, it's real intent is as a *toy*! ;-)
Of course, the thing all of the above concepts have in common is the *risk* that the design imposes on the rider and the control system!
On a sunny day (Thu, 17 May 2012 13:07:01 -0700) it happened Don Y wrote in :
Right, that is the idea of course, me flying in it. I realized I need to buy a bigger house and a piece of land, Maybe down under? (no space here). Just for flight testing :-)
We are all going to die anyways. I'd prefer getting lost in space above some other ways ;-)
Did you see that movie: 'Astronaut farmer?' In it the guy builds a real rocket in his barn. The first flight it tumbles over and he ends up in bandages. Then he starts again, and NASA tries to stop him and sends an astronaut to talk him out of it (played by a well known die hard person), but he starts anyway, and then NASA switches off their communication satellites because NO WAY should he succeed, because if just one man can do what trillions of bean counters cannot, is bad for jobless quotes... But he makes it into orbit and back. Very nice movie, inspiring too.
I am working on a flight computah now, maybe more info in 2 days which that one will be.
On a sunny day (Thu, 17 May 2012 12:20:59 -0700) it happened Don Y wrote in :
DVD subtitles are basically overlay pictures. There are issues, 2 font outlines so not only the font, but the black - or other color and transparency of the outline around it (so for example you an see a white text against a white shirt). And ant-aliasing and all the other goodies.
Yes it is a separate data stream.
In normal DVD there are restrictions on the color palette, size, pixels available (720x576 is all you have full screen, etc. Then there is the issue of synchronization (to the video, or perhaps sound), and very important HOW LONG you display a text, centering, respect borders, and all that different for 16:9 and normal ratios, where you want the subs, etc etc, scrolling texts, exploding texts, what not:
Oh yes.
Lots of free fonts here:
-- You can't have a sense of humor, if you have no sense.
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