Grant Edwards wrote:> On 2005-02-07, Guy Macon <_see.web.page_@_www.guymacon.com_> wrote: > > >>>>Why would he have to move 8MB even once? >>> >>>It doesn't take much video to fill up 8MB. >>> >>> >>>>An embedded system to control a model airplane shouldn't need >>>>to move that much data. A good, fast linux system can fit on a >>>>single floppy, and there is no good reason to collect data at >>>>more than 10 channels at 5 16-bit samples/sec each, that's 200 >>>>bytes/s - 360K/hour. >>> >>>What about data from cameras? >> >>If you are going to add on things that he never said are on the >>airplane, why stop at a camera or two? Why not just assume full >>360 degree IMAX-format streaming video? > > > Because cameras in model planes aren't unusual. 360 degree > IMAX-format streaming video would be pretty unusual.Or non-existent. I've never heard of it. IMAX is usually shot with off-the-shelf Hasselblad still camera lenses and a custom made camera body. No Hasselblad lens can do 360 degrees. And as you implied, the format has *nothing* to do with video. Especially> since the "format" is 75mm prints.Actually transparencies. Admittedly, the working copies are usually referred to as "prints"
Small Linux HW to be carried in a model airplane
Started by ●February 6, 2005
Reply by ●February 7, 20052005-02-07
Reply by ●February 7, 20052005-02-07
On 2005-02-07, Jim Stewart <jstewart@jkmicro.com> wrote:>> Because cameras in model planes aren't unusual. 360 degree >> IMAX-format streaming video would be pretty unusual. > > Or non-existent. I've never heard of it. IMAX is usually > shot with off-the-shelf Hasselblad still camera lenses and a > custom made camera body. No Hasselblad lens can do 360 > degrees. And as you implied, the format has *nothing* to do > with video. > >> Especially since the "format" is 75mm prints. > > Actually transparencies. > > Admittedly, the working copies are usually referred to as "prints"Right. They're "prints" because they're "printed" using another another piece of film and a printer rather than being "shot" in a camera. The film that's actually shot in the camera could be negative or positive, I don't know which is actually used most, and then prints are made from that. -- Grant Edwards grante Yow! I'm also against at BODY-SURFING!! visi.com
Reply by ●February 7, 20052005-02-07
Jim Stewart wrote:>IMAX >is usually shot with off-the-shelf Hasselblad >still camera lenses and a custom made camera >body. No Hasselblad lens can do 360 degrees.http://www.google.com/search?q=theater+%22360+degree+imax%22 BTW, no lens can do 360 degrees, yet 360 degree photography still exists.>And as you implied, the format has *nothing* >to do with video. > >Especially since the "format" is 75mm prints.Film cameras can be retrofitted with digital imaging arrays. (And no, I don't think that an existing array can replace IMAX film, at least not in real-time. It can be done -the Hubble space telescope is only 800x800 pixels, but it digitizes a 35 arcsecond field of view at any given time)
Reply by ●February 7, 20052005-02-07
> Now you are assuming a camera just to defend there being an ethernet > port. Why not streaming video? Why not assume an onboard hamster > with life support in case the plane flies too high? >And you assume that he does not need the Ethernet because he did not tell you why he wanted it. -- Best Regards, Ulf Samuelsson ulf@a-t-m-e-l.com This message is intended to be my own personal view and it may or may not be shared by my employer Atmel Nordic AB
Reply by ●February 7, 20052005-02-07
Grant Edwards wrote:>... snip ...> > Because cameras in model planes aren't unusual. 360 degree > IMAX-format streaming video would be pretty unusual. Especially > since the "format" is 75mm prints.I can remember dreaming of building just such a model. Remote wireless control, and panoramic TV feedback. WWII was on. Never found the round tuit. -- "If you want to post a followup via groups.google.com, don't use the broken "Reply" link at the bottom of the article. Click on "show options" at the top of the article, then click on the "Reply" at the bottom of the article headers." - Keith Thompson
Reply by ●February 7, 20052005-02-07
On Monday, in article <110f9rc7fd8psb1@corp.supernews.com>
_see.web.page_@_www.guymacon.com_ "Guy Macon" wrote:
>Paul Carpenter wrote:
>
>>Firstly with 4 RS232 ports you don't know what he is collecting data
>>from.
>
>Sure we do. He is collecting data from a model airplane.
No what else is ALSO on the plane.
>>Secondly no A/D was specified.
>
>I wrote "bits." I never specified that they were ADC bits. Whatever
>kind of data he aquires, it ends up as bits.
Nope what you wrote was
>From: Guy Macon <_see.web.page_@_www.guymacon.com_>
>Date: Mon, 07 Feb 2005 07:08:55 +0000
>Message-ID: <110e5gdnvtrg166@corp.supernews.com>
....
>Why would he have to move 8MB even once? An embedded system to
>control a model airplane shouldn't need to move that much data.
>A good, fast linux system can fit on a single floppy, and there
>is no good reason to collect data at more than 10 channels at
>5 16-bit samples/sec each, that's 200 bytes/s - 360K/hour.
Which reads as 10 Channels sampled at 5Hz to 16bit width, which
is actually 100 bytes/sec, to then give 360K/hour.
As the original was dig i/o 8-16 bits and there are only 4 x RS232
channels the only assumption I (and probably others),�could come up
for 10 channels would be some form of A/D or inference about what
the RS232 was connected to.
You also assumed it was controlling the plane in the statement above
which I specifically noted in my post that we did not know if this
was a control or monitoring application.
>>Thirdly the flight time is not known.
>
>Sure it is. It is limited by the weight of fuel and the weight
>of providing power for the board. Assuming a special kind of
>model airplane ythat flies for many hours without asking is no
>way to do a preliminary spec of an onboard computer. the default
>assumption should be a normal model airplane.
Why make that assumption?
Especially as you then proceeed to harrangue others about assumptions
about use of cameras and 'hampsters'.
>>Fourthly if any camera is involved for image capture the
>>data size is exponentially bigger.
>
>Now you are assuming a camera just to defend there being an ethernet
>port. Why not streaming video? Why not assume an onboard hamster
>with life support in case the plane flies too high?
The important word you missed was 'if', the specification was for a board
with a fair bit of I/O that may be controlling the plane and/or monitoring
the plane and/or monitoring external parameters.
The only assumption I made was with all that I/O others things not specified
are being interfaced especially when in the plane.
>>Some of the bits might be overspeced,
>
>Indeed. Then again, maybe he does have an onboard camera and hampster...
There is a hell of a lot about the application that is not specified, I put
a lot of IFs in there if you read it again carefully.
--
Paul Carpenter | paul@pcserviceselectronics.co.uk
<http://www.pcserviceselectronics.co.uk/> PC Services
<http://www.gnuh8.org.uk/> GNU H8 & mailing list info
<http://www.badweb.org.uk/> For those web sites you hate
Reply by ●February 8, 20052005-02-08
"hamilton" <hamilton@deminsional.com> skrev i en meddelelse news:dNCdnVsr19Fxy5vfRVn-vA@forethought.net...> How long is the Ethernet cable ??? ;-) >??? wireless lan ??? ;-) Cant help it .. sorry folks!
Reply by ●February 11, 20052005-02-11
