Home
Saturday, May 27, 2017
8:48:13 AM
Users online: 0   You are here >> Home > Tech Talk

Forums | Tech Talk Forums search
Forum FAQ
   
  1 | 2 Next Page 
Ned to make an IR Blaster... with 30 transmitters...
^Faldo^ 
23/8/08 12:13:44 PM
God

So I need to fire 30 SLR cameras at the same time to do a bullet time time sequence. I figure the best way opf doing this is getting an IR remote and rigging up an IR extender and adding a whole lot of

http://www.jaycar.com.au/productView.asp?URL=index&ID=KC5432&CATID=25&SUBCATID=292

I doubt they'll all work if I just chain them to the extender, even though I'd love to. Is there any kind of simple amplification stage that I could add that would work?
I'll be firing Nikon D80s with this IR receiver:

http://www.amazon.com/Nikon-Wireless-Control-Digital-Cameras/dp/B00007EDZG/ref=wl_it_dp?ie=UTF8&a

-DAVE.

-----

Master_Scythe 
23/8/08 1:10:23 PM
Titan

as long as the remote is the same for all cameras, and you wire them in paralel, not series, yeah you should be able to just whack them all on.

you'll drain the batteries faster, but not reason you cant.

I added an extra beam to my tv remote this way caus it was horribly 'accurate' and i hated having to aim.

-----
4200+X2 939, ASUS A8N-SLI-D, Ati HD3850, 1gb,1tb total HDD, 109 DVD, LG DVD-rom.
Quote by Girvo
I've got a wicked tiny one that is ridiculously sensitive.



LordBug 
23/8/08 6:51:14 PM
Immortal

I'll admit, my electronics knowledge is rubbish, but at least the remotes for Nikons are cheap ($8 on eBay, that's including postage).

Do something like MS suggests - get one, or two, or three of these remotes, hack them apart, and see if you can't wire in a bunch of IR LEDs in parallel (Obviously you'd need to supply a bit of extra energy to these little fellas).

If you're getting to play with a setup which includes 30 D80s, well heck, I wish I could be in that situation :P


Just to clarify though - Is this a case of 30x cameras in an orb type configuration around a single point of the bullet's path, or are they in a row to capture the bullet as it travels along?
If it's in a row, wouldn't you require a delay for each camera to be firing?

P.S. Who's Ned, and why should we help him? ;)~


Edited by LordBug: 23/8/2008 06:56:36 PM

-----
Lord of nothing except my own dreams, so it's Bug to you.


I love you Sharleen *)

scootre 
24/8/08 11:24:55 AM
Guru

Let me get this right... you want to freeze the motion of a bullet using DSLRs?

If that is the case... then you will need:

A completely backout-able room... high speed flash units - but not off the shelf stuff; and a trigger system. Again, not off the shelf.

And that is just the start of the problems you will face. Using an appropriate high speed flash unit, a pulse duration of one micro second (that's one millionth) will partly freeze the a slug from, say, a pistol or rifle. You will still get some blur.

The trigger device will have to be made in such a way that you can dial up and down a delay time in the region or micro- or nano seconds.

So in short, Jaycar might be the place to start but will certainly not carry some of the specialised parts you will need for such a project.

I recommend you research the work of Harold Edgerton (at MIT) as well as Stephen Dalton. Edgerton was the inventor of the flash tube as we know it today and pioneered high speed photography. Dalton is a very famous bird and insect photographer who, along with a friend, developed some pretty cool methods and equipment for capturing bugs and birds that fly and zig-zag and high speed. I can recommend two of his books: "Split Second" and "Bourne on the Wind".

I have had a little experience in high speed photography and built my own high speed trigger with modified flash to capture stuff at about 20um (1/50000th sec)... but not good enough for bullets. I also have one of Edgerton's books on how to build high speed flash units, called "Electronic Flash, Strobe", though it may be very hard to obtain or out of print.

Tell me more about your project.

-----

battlefield_gir 
24/8/08 5:27:56 PM
Titan

make a sound trigger and stager the times

http://www.diyphotography.net/diy_high_speed_photography_at_home
http://www.diyphotography.net/diy_sound_trigger_for_sigma_ef_500_flash


Edited by battlefield_gir: 24/8/2008 05:29:30 PM

-----
Minister for Education, Innovation, Science & Research.


R.I.P Josh Woods

Goth: Am I the only one who somehow swam through the wall of the vagina and got lost/stuck inside




"There is no probl

robzy 
24/8/08 6:28:24 PM
Hero
Immortal


scootre: He said bullet time, not a photo of a bullet :P

http://en.wikipedia.org/wiki/Bullet_time

Rob.

-----
עם ישראל חי

scootre 
24/8/08 6:56:21 PM
Guru

Ahhhh..... so you know what that means? It means all my good advice just went out the window. :)

-----

AccessDenied 
24/8/08 9:59:06 PM
Hero
Titan


http://www.lirc.org/transmitters.html

There you go..

Have fun..

AD

-----
173 points
SaltyPeanut, Mills, Lanzer, Damo, Bastard DiStOrTeD, Leonid & 1000 to Dexxie for having a pierced tongue!
-1:Logicprobe
1 donated:800_series
99% of girls on the internet are interested in sex. The rest ARE Mills.

sirsquidness 
24/8/08 10:44:36 PM
Champion

One problem I've noticed. Bullet time staggered the cameras by something like 10ms/frame. Doign the way Master_sycthe suggested would result in them all going off at the same time.

The only other way I can think of is to get a PIC to do the pressing work, or some form of mechanical system that staggers it. Perhaps something like rig up the buttons so they're metal contacts on a roll of something and roll a metal marble down it? It could work! ... and probably eaiser than doing a PIC too.

-----
The one. The only. SirSquidness.

If I have a witty signature, will it make people love me?

LordBug 
24/8/08 11:53:05 PM
Immortal

Would it be too hard/expensive to do something with the wired remote port? Could be a bit more stable to hack something that way, as opposed to relying on IR controls.

-----
Lord of nothing except my own dreams, so it's Bug to you.


I love you Sharleen *)

Master_Scythe 
25/8/08 12:07:49 AM
Titan

I think lord bug is onto something.

Get a wired remote for the camera, push the 'take picture' button, and see what pins on the connector do what.

then get a PIC or something simmilar to replicate that.

-----
4200+X2 939, ASUS A8N-SLI-D, Ati HD3850, 1gb,1tb total HDD, 109 DVD, LG DVD-rom.
Quote by Girvo
I've got a wicked tiny one that is ridiculously sensitive.



freespace 
25/8/08 12:51:13 AM
Hero
Titan


Vote for the wire remote, much more reliable, though there is no reason you can't get a _single_ IR repeater from jaycar, and modify it to run 30 IR LEDs pretty much taped over IR port of the other 29 cameras.

This sounds like an interesting project, and I for one, volunteer my lowly electrical skills (design, testing, soldering, PIC, programming) :)

-----
By perseverance the snail reached the ark.

http://www.shuningbian.net - blog
http://anonshare.pictorii.com - share files anonymously
http://dailydiscovery.b3ta.org - learn something new
its f reespace damn it!

^Faldo^ 
25/8/08 10:18:08 AM
God

So at the moment it looks like I'll have a Jaycar IR extender with 30 leads running out of it instead of a single IR transmitter.

Each lead will terminate in an IR transmitter and will be placed in front of a D80's IR receiver.

FTR, I'm photographing a car smashing through a sheet of glass, so I don't need sound triggering. Just hitting the remote at the right time should work.

And even though I'd like to rig up a serial interface and stagger the timing of the shots, I simply don't have enough time or money to develop that system. I have less than fifty bucks to spend to get this shot right -- thankfully I'm operating on favors and borrowed gear.

The IR system works because it's less than a buck for every transmitter: if I wanted to do things the superior wired way I'd need 30 proprietary plugs, not to mention some kind of independently controlled rig that can fire them off with slight delays.

And I'm also planning to use two slow motion (50 FPS) video cameras and two standard (25 FPS) video cameras in this shot.

Come see the show! It's on in 3-ish weeks, I think. http://www.cserevue.org.au/rms/

-DAVE.

-----

Sir_Substance 
25/8/08 11:11:42 AM
Immortal

Quote by ^Faldo^
FTR, I'm photographing a car smashing through a sheet of glass, so I don't need sound triggering. Just hitting the remote at the right time should work.



wouldn't it be easier to hire a high speed camera for a day?

-----
The Score: LogicPr0be, Twinair, Brains, TheDrake, Caelum, Cynic*, Hallowed, Juggalo Scrub, Bastard Child, Beefeater, Damo, Nickeax.
Quote by superfireydave
Let's play spot the drunk! ;D




^Faldo^ 
25/8/08 11:42:07 AM
God

I'm getting two (I hope). The point of the SLRs is that after the high speed camera brings time to a smooth halt, the the viewpoint spins around in frozen time to another angle -- see also The Matrix.

-DAVE.

-----

stadl 
25/8/08 5:43:11 PM
SuperHero
Titan


You may be fine with simply running a second driver circuite that will allow you to run the 30 IR tranmitters off in place of the existing one.

You'll need a bit of practice to hand time the use of that remote, since in my experience the cameras are a bit laggy when using it.

Hopefully each camera is consistent in it's decoding of the IR signal and firing because a millisecond difference will ruin the smoth flow of the shots as the car and glass appear to jitter back and forth.

It's a hell of a bit task, and the time synch is a small part of it.

I'd not like the idea of building the scaffolding required to support 30 cameras with identical prime lenses all the exact same distance from the centre point, and set them all to manual focus at the same distance with a narrow enough aperture for a usable DOF in this test - and the rig has to withstand a car crashing through glass nearby.

I hope you have a heap of lighting and high enough ISO to allow a fast enough shutter speed to freeze the car and glass with the narrow aperture - don't forget to set the exposure on all the cameras with the car in place before you crash through, and hope the sun doesn't move much between setup and filming.

Best of luck, if you can pull it off it'll be an awesome result.

-----
...so brilliant in fact, that by simply harnessing the power of one live frog, it.. it.. uhh.<poke> <poke>
World domination has encountered a momentary setback. Talk amongst yourselves.

Waffles, Lots of Waffles... And Chips...

sirsquidness 
25/8/08 7:14:27 PM
Champion

I think the question that really needs to be asked is... Will we see the fruits of your labour in an upcoming atomic mag? *cough*

^Faldo^
And even though I'd like to rig up a serial interface and stagger the timing of the shots, I simply don't have enough time or money to develop that system. I have less than fifty bucks to spend to get this shot right -- thankfully I'm operating on favors and borrowed gear.



I woudln't imagine it being *terribly* expensive of time consuming. At worst, some form of serial communication from a small PIC (such as the picaxe) to a pile more of them with lots of IR LEDs. But from what you've said, yeah, it probably is out of your range unfortunately. 'twould be awesome to see a home brew version of real live bullet time, not just bullet frame :P

-----
The one. The only. SirSquidness.

If I have a witty signature, will it make people love me?

LordBug 
25/8/08 8:58:32 PM
Immortal

Now that I see the second time following the first, I understand that it's not to do with taking photos of a bullet (Which at first I was thinking was a bit ambitious for a D80, let alone 30 of them :P).

So. A budget of $50 to trigger >$35,000 worth of equipment. Beancounters are the devil, ain't they? :P

Anyway. Depending on the setup, you might be able to get away with less transmitters, as the elcheapo remote is able to trigger my D50 from a few metres away in direct sunlight. If lucky, just a couple of choicely placed boosted transmitters may do the trick, though at the same time opens up a bit of risk.

Sounds like a fun project either way. Hope the video gets uploaded :)

-----
Lord of nothing except my own dreams, so it's Bug to you.


I love you Sharleen *)

^Faldo^ 
28/8/08 4:25:17 PM
God

So I've built the kit, but I'm worried it won't power 30 diodes.

My limited knowledge of electronics says that after the signal is deconstructed and reconstructed, it gets managed by a transistor. If i replace this transistor with a chunkier one with identical specs except for current handling, will I be able to drive the 30 LEDs?

The transistor I'm using is labeled as a BC327 on the schematic, and the transistor is labeled C32740 (line break) PH12. To me that narrows google's results to a Philips transistor.

Like this one -- http://www.datasheetcatalog.org/datasheet/philips/BC327_3.pdf

Can anyone point me in the direction of a more capable drop in replacement transistor, or am I on the wrong track?

Schematics scanned as PDFs; as rar file; 2.35MB -- https://www.yousendit.com/download/Q01HRGx5d0lubHhjR0E9PQ

-DAVE.

edit: PS: the meat's on page 1 and 3


Edited by ^Faldo^: 28/8/2008 4:28:19 PM

-----

freespace 
29/8/08 12:14:37 AM
Hero
Titan


LEDs generally draw very little current, and you have 800mA to play with. If each IR LED draws < 26mA you should be able to power them all without swapping the transistor.

Having a look at the schematic, it is setup so the IR LED get ~21mA, which suggests you can hook up 30 of these in parallel without changing anything. However, the 150ohm resistor in the power rail restricts you to 60mA which is not enough to power 30 IR LEDs at 21mA. You will need to re-configure the circuit to deliver that 30*21mA to the transistor. If you can provide the specs of the IR LED, I can better tell you what you need to change.

Also, I assume you have tested the gadget in its current form, and it is working?

Cheers,
Steve

-----
By perseverance the snail reached the ark.

http://www.shuningbian.net - blog
http://anonshare.pictorii.com - share files anonymously
http://dailydiscovery.b3ta.org - learn something new
its f reespace damn it!

  1 | 2  | Next Page 
Forums | Tech Talk