DIY 4x5" scanner back

[Peter De Smidt]

Take a look at the images Duckie produced with his system. http://mosesblah.wordpress.com/2010/...camera-images/

[papah]

Here are some similar projects:
http://golembewski.awardspace.com/index.html
http://johnvanhornphoto.com/lgformat...amera2007.html
http://www.cs.ubc.ca/~heidrich/Papers/EI.04.pdf

I've attached a scan I did with a Canon LiDE 20 duct-taped to an 8x10...

[Lenrick]

The IRIScanner arrived yesterday.

Now I understand how the scanner knows how fast it is being moved over a surface. Wheels underneath the scanner are connected to a gearwheel that sits between a LED and a photo detector (please see attached pdf). In order to trick the scanner so that it thinks it is being moved over a surface I have to spin the wheels or in some other way turn the gearwheel, it could also work if I get the LED to blink.

(It might have been better to buy one of those scanners that pulls the paper by themselves, and remove the bottom part of the scanner.)

I have done some calculations and concluded that the gearwheel in the IRIScan should turn with approximately 40-150 rpm (depending on resolution and the speed of the motorized tripod head). My idea is to connect it to a small DC motor. I found this motor: http://www.micromotorssrl.com/motor_l149/l149_pg.html
what do you think?

At the moment I cannot get to the illumination light source (which must be a LED), but it doesn't seem to be any problem to block the light. The sensor and light source are hidden in a casing which I cannot open at the moment. The lens array is glued to the casing, I might be able to get to the light source when I have removed the glue and the lens array. But first I want to concentrate on the gear wheel problem.

I took a quick normal scan of a picture on a book page, see attached file.

I also, quickly, tried to do a 'proof of concept image' with the scanner mounted on the camera. I tried to turn the wheels with one hand and turn the camera with the other hand. See attached file. With some practice I think I could get a decent image. With a smooth wheel turning and smooth camera turning even better. And finally with lens array and light source removed even better.

Any comments?

[Lenrick]

Silly me. The simplest way to trick the scanner must be to mask or remove the gearwheel LED and use an external blinking LED. I just need to figure out at what frequencies it should blink and how to build that type of circuit.

-edit: A rough estimate puts the blinking LED frequency in the range of 20-200 Hz (depending on resolution and the speed of the motorized tripod head).

[Lenrick]

The gearwheel LED is not a visible light LED, it is a IR LED.

I tried to block it an use the strobe function on my iPhone LED but nothing happened. But when I, with fast movements, removed the blocker and put it back a few times the scanner seemed to start scanning. And when I didn't see the LED shine I thought of IR LED.

I then tried, with the gearwheel LED blocked, to point a TV remote controller towards the photo detector and try to scan in mid air. Worked perfectly.

I need to build or buy a small thing that runs on batteries and flashed a IR LED at about 50 Hz. If the frequency could be adjustable between roughly 10-200 Hz it would be even better. Is it a good idea to try to rebuild an old TV remote controller, do you think?

[ramon]

Do a search about "led flasher" or "led blinking"

Maybe the simplest way is using NE555 IC

http://en.wikipedia.org/wiki/555_timer_IC
http://wild-bohemian.com/electronics/flasher.html
http://www.satcure-focus.com/tutor/page11.htm
http://www.bowdenshobbycircuits.info/page5.htm
http://www.qrp.pops.net/LED-2008.asp

[pound]

For anyone who is thinking of building a scanner camera like the ones Michael Golembewski from The Scanner Photography Project is building. I found a instructive blog which I haven't seen anyone link to before: Duckie's Blog

here is another instructive blog post on disassembing the LIDE 20 with more and clearer photos

[Ramiro Elena]

That's nice pound. I'd like to see something like this on the modification of the black strip. I've never understood what exactly needs to be done to it. The one I modded only got me a worse image.

[Math]

How about getting a very fine groundglass and sweeping the IRISCAN over it? I've been looking into finding a more traditional A5 sized scanner, but they're not easy to find.

[Steve Smith]

I need to build or buy a small thing that runs on batteries and flashed a IR LED at about 50 Hz.

Use the 555 circuit already suggested but instead of an LED, connect the output (pin 3) via a 10K resistor to the base of a transistor. Connect the rest of the transistor in place of the IR receiver. Run it from the scanner power supply.


Steve.