Go Down

Topic: NIKON D50 in space (Read 1 time) previous topic - next topic

gbm

Jul 07, 2010, 05:09 am Last Edit: Jul 07, 2010, 05:14 am by gioscarab Reason: 1
Hi. I am planning to use a helium baloon to send a nikon d50 to 30.000 feet . I need some advices on communication. Do you know any possibility to send with radio waves with a range of 40km coords and altitude?

I see this things:
http://cgi.ebay.com/Midland-GXT1050VP4-30-MILES50-CH-SOS-SIREN-B-NEW-12295-/150457360273?cmd=ViewItem&pt=2_Way_Radios_FRS&hash=item2307f51f91

The most stupid thing would be use two of this tranceiver and 2 arduino with 2 piezo and 2 miniactuator to press the button and communicate with morse  :o
But should works...
Community robotica / programmazione Arduino
www.gioblu.com

cr0sh

Quote
The most stupid thing would be use two of this tranceiver and 2 arduino with 2 piezo and 2 miniactuator to press the button and communicate with morse


That would be "most stupid" - it would be better to set up an asynchronous communication protocol, and tie the Arduino into the PTT (push-to-talk) switches using a relay or transistor/MOSFET switch to handle the back and forth comms, and send the data in packets...

Fortunately, this has already been done for you - look up "packet radio".

Note that I don't know if this is legal to do (ie, send data over those frequencies) if you don't have a ham license. Check your local/national laws...

:)
I will not respond to Arduino help PM's from random forum users; if you have such a question, start a new topic thread.

Intenzity

You should read this guys experience -

http://www.sparkfun.com/commerce/news.php?id=389

He works at Sparkfun and had access to all the hardware he wanted and sent up a rig to photograph space.....and he didn't get it back. He was not able to recover it even with GPS and other tracking mechanisms.

You might want to rethink sending a $1000 camera up to where it is going to be 50 degrees below zero and you might never see your camera again, even with GPS and other tracking mechanisms.

Good luck though, but read his article, he goes into great detail and it is going to be an ongoing series as he details all the elements of his project. He talks about radios a little in the first article.

kg4wsv

RF communications and flying balloons are typically regulated by country.  I'm in the US.

We use APRS for tracking and recovery.  I've been involved in over 50 flights and we've got a 100% recovery rate* using standard ham tracking rigs.  There is a network of repeater stations and internet gateways that help us communicate with the payload even if it goes over the horizon.

It requires a ham license, but if you can use an arduino you can pass the technician exam.

Some of our guys have flown the Xtend radios (like the sparkfun guy used) as an experiment and they're great for line of sight comms.  I think the measured range was about 42 miles, and the terrain got in the way.  Once it goes over the horizon, you're hosed.  There's just not enough power.

A local ballooning epert also recommends the SPOT as a backup tracker.  It's commercial and satellite based, so there's no licensing (just fees) and it's got good coverage.  It's not good for displaying a nice flight path or finding out how high you went, though.

A big problem will be cold - specifically, I'd make sure the payload bay is heated so that the mechanical shutter in the D50 continues to function.

-j

* OK, a few have landed in the river, or spent a night or two in a tree, but we got them back.

gbm

WOW!!!! Thank you very much for your advices!!
I am taking a look to your res!

My problem is:
- camera / electronics heating
- camera tilt/pan

This project has a photo goal. I would like to shoot earth, and then some shoots to stars. my problem is that i can't see what nikon sees. For this reason if I want specific frame I have to teach to a computer to get images from nikon - analize it and with a computer vision system choose the correct frame (earth on the down-left, space to the right)
Community robotica / programmazione Arduino
www.gioblu.com

kg4wsv

#5
Jul 07, 2010, 05:26 pm Last Edit: Jul 07, 2010, 05:27 pm by kg4wsv Reason: 1
I suspect your problem will be much more fundamental than pan/tilt.  Your platform is spinning on the end of a pendulum.  It is possible (but non-trivial) to account for those and point your instrument.

One of our teams just took a crap-load of pictures and used some software to stitch them into a nice hi-res panorama.

As for pictures of stars, not sure how much luck you will have.  I've never seen any stars in our balloon pictures, but with a controlled exposure of a pointed SLR it may be possible.

Oh yeah, make sure you aren't pointing at the sun; you can easily fry your sensor, especially without the benefit of the atmosphere filtering it.

There is very little atmosphere, so heating via directly-attached heating elements is generally more effective than other methods.

Condensation is also a big issue.

I'd get a cheaper camera (e.g. one of the older canon cameras that can run CHDK), and a video camera, and do some testing before I flew the D50.

-j

graymalkin

At 30,000 feet heating shouldn't be a problem, in fact it shouldn't be too bad at 100,000 feet provided you use no moving parts, I beleive most ICs and solid state components are operable at somewhere near -50C, at that height it should be only(!) -40 ish, but... what you could do (don't scream), is use the far stronger from the sun as a heat source.  If you were to add a large piece of black painted foil connected with thermal gloupe and thermal tape to your more sensitive parts you should get a reasonable heating effect from absorbing radiation.  Just an idea...

Not sure how radiation will affect other parts, be safe an include a neodymium magnet :P

kg4wsv

Quote
At 30,000 feet heating shouldn't be a problem, in fact it shouldn't be too bad at 100,000 feet provided you use no moving parts, I beleive most ICs and solid state components are operable at somewhere near -50C

Wrong.

Most parts are commercially rated to 0C at the lower end.  Many parts also have an industrial or automotive version rated to -40C.  A balloon flight should be prepared for temperatures down to -70C.  -40C is almost assured, even lower is common.

I used a commercial (0C) rated DS1307 RTC on one flight (made a mistake ordering) and the device quit working just below 0C.  luckily the clock kept ticking and when the part "thawed" it had kept the correct time and began reporting it again.

-j

natman3400

What you could do is make a micro sattlite and launch into low orbit, ant use a tiny blast to get some spin on it, then just snap photos at ranndom, and have it send back thumnails. If it looks good, keep it.
I am working on something like this whith many oter people for my local university. For heating, we are areogel insluating, and putting 1 volt less then the max input into a voltage regulater when the temp starts to drop. In our vaccum/cooling chambers, it has proven to be more then enough. Turning it on for just a short time was enough to keep it in safe limits for well over a day.

kg4wsv

Quote
What you could do is make a micro sattlite and launch into low orbit,


Yeah, 'cause everyone knows LEO is much cheaper than US$200 for a balloon and helium.  :P

-j

Funky Diver


natman3400

Well, we are working on a $300 temp unit. including launch. It looks like it would use a $200 rubber burning rocket.
Spawned from the joke we made during figuring out how to launch, " Just buy it a ticket for spaceship 2 and throw it out the window."
And yes, CUBE SATS ARE WIN!
The only problem with the rubber rockets is our simulations show that we cant throw it into a stable orbit eaisly, hence the purposful decaying orbit. Don't want to lose it and have it hit the iss or something, and have the full wrapth of nasa upon us. So to save money, we are working to toss the sat out before the rocket hits the hight it would burn up at during the fall, and salvage the rocket.

That said, i was just giving an idea to provide heat.

Graynomad

I doubt you'll have any luck photographing the stars, that's normally a 20-30 second exposure even at f4 and ISO 3200. And of course the camera has to be still or better still tracking the stars on an equatorial mount.
Rob Gray aka the GRAYnomad www.robgray.com

natman3400

You could get pictures of the brightest stars with a normal picture.

Graynomad

#14
Jul 20, 2010, 12:40 am Last Edit: Jul 20, 2010, 12:40 am by graynomad Reason: 1
Quote
You could get pictures of the brightest stars with a normal picture.


Possibly, I've only ever tried to get as many as possible including the Milky way. I'd have to say though that a black frame with five dots would not be that interesting photographically. But on the other hand to have your own "Hubble" in near space would be neat.
Rob Gray aka the GRAYnomad www.robgray.com

Go Up