Daniel Reetz, the founder of the DIY Book Scanner community, has recently started making videos of prototyping and shop tips. If you are tinkering with a book scanner (or any other project) in your home shop, these tips will come in handy. https://www.youtube.com/channel/UCn0gq8 ... g_8K1nfInQ

Camera Triggering

Everything camera related. Includes triggers, batteries, power supplies, flatbeds and sheet-feeding scanners, too.
Ryan_phx
Posts: 63
Joined: 29 Dec 2010, 14:51
E-book readers owned: Nook, Kindle DX
Number of books owned: 0
Country: USA
Location: Sandusky, OH

Re: Camera Triggering

Post by Ryan_phx » 31 May 2011, 10:29

kylefoley2000 wrote:Hi,

first post. I'm having a lot of trouble building a trigger. The information on this site regarding building a trigger are extremely vague. I have found this site
http://www.instructables.com/id/Remote- ... ras/#step1

But I don't know how to connect that to a USB.

Also at this SDM site things are rather vague at how to begin.

http://stereo.jpn.org/eng/sdm/index.htm

If there is a button to push that will trigger the cameras I don't see why a computer software program is necessary.
Not all cameras can use that type of switch, so check that before you start building.

Some cameras are built to work with a remote trigger, and some aren't. Many of us use the Canon A480 or similar cameras, and those are really just meant to be simple point-and-shoot cameras, unlike the feature-rich SLRs. So to use a remote trigger with an A480 or similar Canon camera, you have to use the CHDK software to teach the camera to trip the shutter when it receives a pulse from the switch. Expensive cameras that come from the factory ready to use a remote trigger already have that software built in.

itsme

Re: Camera Triggering

Post by itsme » 13 Sep 2011, 08:38

curious wrote: [*]Powered USB hub with switch (Tom Horsely): Splice a switch (button) into the power cable of a powered USB hub, plug SDM cameras into powered USB hub, push the button to send a 5-volt pulse to the cameras that triggers them based on SDM code -- http://home.comcast.net/~tomhorsley/har ... %20Trigger
[*]something similar to above, also by Tom Horsley -- http://www.diybookscanner.org/forum/vie ... 9209#p9209
Nice tuts but I still have a question: when the memorycard is locked and the USB-port of the camera is in use for the USB-remote then how the taken image/ photos will be transferred to a computer?

Turtle91

Re: Camera Triggering

Post by Turtle91 » 13 Sep 2011, 09:29

itsme wrote:Nice tuts but I still have a question: when the memorycard is locked and the USB-port of the camera is in use for the USB-remote then how the taken image/ photos will be transferred to a computer?
I'm not sure what you mean by the memory card being "locked"??? In my case, using CHDK, I move the little tab to the locked position to allow CHDK to automatically load when I turn on the camera. The pictures are still stored on the card just like normal. You can still remove the card and transfer the pictures directly to a computer via a card reader.

One other option is to take all your pictures - storing them on your memory card - using the usb remote trigger. Then when the scan is complete you can unplug the usb cable from the hub and plug it directly into the computer - transferring the pictures via that usb cable. I'm not sure about the software, but I think you may have to turn on the camera without loading the SDM or CHDK to allow it to transfer via usb.

I am looking into a triggering method mentioned earlier by TomHorsley
TomHorsley wrote: Here's another possibility (that still needs SDM or CHDK): This test script can detect changes in light level by querying the Bv property (whatever that is):

Code: Select all
@title Bv test
:loop
press "shoot_half"
sleep 500
get_prop 34 a
print "Bv is", a
release "shoot_half"
sleep 500
goto "loop"
end



So, if you have your lights on a switch, you could have an SDM script running that just goes ahead and takes the photo when it sees the lights come up.

Got this from a question I asked over on the CHDK forum:

http://chdk.setepontos.com/index.php?topic=6203.0

This might make it simpler to just use the USB cable for nothing but file transfer rather than as a remote control.
I have the camera able to read the light levels - although I think I need to give it a little more time - changing the "sleep 500" to sleep 1000" - to sense the light. I think my camera might be a little slower...
This frees up the usb port completely and lets me transfer directly to computer without switching wires around.

....in theory anyway...I am still at about 69% completion - haven't finalised everything yet...

Cheers!
Dion

reece.arnott
Posts: 10
Joined: 28 May 2011, 09:24

Re: Camera Triggering

Post by reece.arnott » 14 Sep 2011, 01:46

If you are using a Webcam that is a UVC standard then you can actually just send the right command and have it capture a still image for you.
I have worked out how to do it in Linux but I am currently unsure how to do it in Windows.

Linux does not actually implement the Still Image Capture part of the standard so you need an additional program specifically to do this.
Windows documentation seems to imply that the usbvideo.sys driver does implement Still Image Capture so it should just be a question of finding out how to communicate with the webcam.

See my documentation at http://dspace.org.nz/2011/09/11/bookscanner-project/

itsme

Re: Camera Triggering

Post by itsme » 14 Sep 2011, 08:42

Turtle91 wrote: I'm not sure what you mean by the memory card being "locked"??? In my case, using CHDK, I move the little tab to the locked position to allow CHDK to automatically load when I turn on the camera. The pictures are still stored on the card just like normal. You can still remove the card and transfer the pictures directly to a computer via a card reader.

One other option is to take all your pictures - storing them on your memory card - using the usb remote trigger. Then when the scan is complete you can unplug the usb cable from the hub and plug it directly into the computer - transferring the pictures via that usb cable. I'm not sure about the software, but I think you may have to turn on the camera without loading the SDM or CHDK to allow it to transfer via usb.
Thank you for your reply. Much appreciated.

With locked i mean write protected. Like you say you have to move that little tab to the lok ( = write protected ) so it will not store new data any more.
That's why i wander how pictures are captured.

It's maybe clear for you if I describe our scanner: it are 2x Canon S95 with a memory card. On this memory card there will be boot-software for the cameras ( SDM ) .
The video ( cinch connector ) is connected to a scart-adapter for live video-streaming on a television.

So: is it possible that after the boot sequence of the camera the memory card must be removed to unlock the write protection? Or must it be replaced with an other card?

Turtle91

Re: Camera Triggering

Post by Turtle91 » 14 Sep 2011, 08:53

I haven't played with SDM, only CHDK, but since SDM is based on CHDK I would think that they both work the same.

With the switch moved to the write protect position, using CHDK, the camera will still save pictures to the card. You do not have to replace it with a new card to take pictures.

If you want to use USB to transfer the pictures - I THINK I read somewhere that you have to boot the camera without the CHDK loaded. That means you would have to take the card out and flip the switch to UNLOCK and then reboot the camera. Someone please correct me if I am wrong about this.

itsme

Re: Camera Triggering

Post by itsme » 14 Sep 2011, 09:11

Turtle91 wrote:I haven't played with SDM, only CHDK, but since SDM is based on CHDK I would think that they both work the same.

With the switch moved to the write protect position, using CHDK, the camera will still save pictures to the card. You do not have to replace it with a new card to take pictures.

If you want to use USB to transfer the pictures - I THINK I read somewhere that you have to boot the camera without the CHDK loaded. That means you would have to take the card out and flip the switch to UNLOCK and then reboot the camera. Someone please correct me if I am wrong about this.
Thank you again.

I looked it up and yes, SDM is CHDK based. It's weird that the write protection on the memorycard is overruled by the camera. That is probably why i didn't understand where the images will be stored.

I will trial by error. It's a new construction so nothing can be lost :)

gwrtheyrn

Re: Camera Triggering

Post by gwrtheyrn » 19 Sep 2011, 09:45

(Repost from my blog...)

On the left side of the Canon EOS 450D (and probably on any other EOS camera), there’s a connector for a remote shutter trigger. You can make your own remote trigger by sticking one side of a 2.5″ jack-jack cable into the connector, while bridging two of the pins on the other side of the cable.

Image

By connecting pin 1 + 3, you can focus and trigger the shutter; connecting pin 2 + 3 triggers autofocus only. With that information, you can easily make yourself your own remote trigger, maybe even an automatic trigger using the arduino and some sensors.

akashic.librarian
Posts: 2
Joined: 28 Oct 2011, 13:23
Number of books owned: 0

Re: Camera Triggering

Post by akashic.librarian » 31 Oct 2011, 19:26

Cheap 'n Dirty --->

Image

Code: Select all

http://www.amazon.com/Pyramid-Alloy-Mountain-Cable-Brake/dp/B000AO7H16/ref=sr_1_1?ie=UTF8&qid=1320103050&sr=8-1
Typical bike brake cables WITH housing ~ 60" --- notice what a long, long trip the cables take in Daniel's newest v.

Combine this with Mario K's "Mechanical Trigger Using Wire Cables"

Code: Select all

http://www.diybookscanner.org/forum/viewtopic.php?f=1&t=914&p=9792&hilit=+bicyc


and his Youtube demo

Code: Select all

http://www.youtube.com/watch?v=ohx2uteHWeY
and you''ll be happily considering the <$100 Kodak 16 MP point-shoot-throw-away models ;)

They'll be flyin' in my rig .... soon :D

******* edit *************

Code: Select all

shawn@bikeworldusa.com  
kindly returned my call today,
and informed me that the product # to order directly from them is TP 232,
and a basic cable-in-housing that is termed 60x65 (60" housing length, 65" cable length) is TP 048.

He also mentioned that the mounting ring is metal, not plastic.
That said, this is a cast alloy product - someone in a review on Amazon, I think,
criticized that for cracking whilst they stressed it in a manner it wasn't designed for :roll:

... don't think our uses here should pose any such stress ;)

Their site is obviously

Code: Select all

http://www.bikeworldusa.com/
Cheers!

darrinjk

Re: Camera Triggering

Post by darrinjk » 07 Nov 2011, 15:26

Hey guys, thinking on this I was wondering that if since we are already using bike levers and cables, why not simplify even further using also the brake calipers that often times are included in a set.

Image

Take the pads off. Then, on the one side, use a 1/4 20 bolt and nut to secure camera directly to caliper. On other side, use some little do-dad that will reach to the camera button. Depending on your camera the pad itself may work.

I haven't tried this, but I'd like to hear what you think. I dont actually have any calipers myself to try with or I would. Do you think a caliper like this is wide enough to accommodate a camera inside?

I especially interested in this for integration with Daniels new CNC model. The triggering arm he has on his machine doesn't seem to have instructions anywhere.

Post Reply