DO NOT screw the lens all the way down. Doing so will destroy the glass over the sensor and thus destroy your camera.
You need to just screw it down snuggly so that the filter rests on the sensor glass.
Here is the 850DF10 filter link and its transmission curve.
Here is the 880DF20 filter link and its transmission curve.
Costs $20/ filter + free shipping**
**See update at bottom for method of not needing to cut the lens**
So last week I purchased two band pass filters from the ebay seller omegabob2 who is the main supplier of band pass filters for the members on the nuigroup forum. You can find his ebay store as a link on my blog or here
So I needed a 850nm filter due to my purchase of IR LED strips from environmentallights.com coming up, and omegabob2 has one filter available, a 25mm one. I bought two of them, and when I got the package discovered that he also had included two extra filters: a 60mm one and a 10mm one. Both are products he does not currently sell on his site. He included a nice note suggesting I try them out and that he has seen some of my work on the forum, though hasn't himself registered to the site yet. I was excited for the 10mm one, as I instantly knew what I was going to try with it!
So I grabbed my PS3 Eye cam, and worked at it to fit the filter between the lens and the image sensor on the board. Below are pictures showing how it worked out. I am very pleased with the results and will ask that he include these 10mm 850nm filters on his site as I know Ill be purchasing more of them very soon.
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What the lens/lens holder looked like originally after I had cut the IR blocking filter out (as seen in my previous videos)
The 850DF10 10mm 850nm band pass filter from omegabob2's ebay store
The filter is too big in diameter to fit directly into the hole left when I took out the IR blocking filter.
Using an exacto pen knife enlarge the hole and dig plastic away from the lens so that it also sits lower (need to be this tool and not a large razor blade as you need the precision from this small knife)
Showing the enlarged hole for the filter to sit in.
The filter sitting in the hole.
Putting the lenses back on.
The holder does not screw all the way back down to what it had before. So just twist the screws until they are snug and the piece of glass over the sensor and the band pass filter are as close together as they can be without shattering the sensor.
Showing the filter looking at the 850nm LEDs that are used on my LED-LP table using the PS3 Eye cam software that is provided with AlexP's PS3 Driver download.
Screenshot from tbeta with the new filter on.
The addition of this filter may fix the focus problem, as you can see in the image above, everything is pretty much in focus.
The filter does a great job at filtering out light other than the 850nm band as it should.
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UPDATE 2/27/09
So I received some more filters from Jim (omegabob) yesturday. The 11.4mm 842DF33 fits perfectly inside the PS3 lens without any carving of plastic needed as seen in the procedure above. Here are some shots using a different camera lens than the one above:
A piece of floppy disc (old method) and the band pass filter (new method)
Omegabob should be posting these filters up soon to be able to purchase.
Posts
so after going through both floppy disk, exposed film and this band pass filter, which one is giving you the best results? Also, how is each one reacting to different ambient lights? thanks!
ReplyDeleteThe floppy disk and exposed negative are both known as "poor man techniques" and should only really be used in learning about the optical-based multitouch systems and never in a final project, as they are not true band pass filters and yield sub-par results compared to a proper band pass filter. You want the webcam to only see the wavelength of light that is coming from your IR source and a real band pass filter is the best way to do this. For most setups, do not go over 850nm IR lights, as higher wavelengths will be less bright and produce fainter blobs, thus more difficult to get good results out of.
ReplyDeleteHey peau, I am doing something similar to your led-lp table. Can you post some pictures of the LEDs you used? I've constructed a frame similar to your led-lp frame, but the brightness I got is troll compared to yours. The IR-leds I got are the kind used in remote controllers at 3v 940nm. What kind are you using? Also, what are you using to power them up?
ReplyDeletesheley:
ReplyDeleteLook at this blog post of mine:
http://peauproductions.blogspot.com/2008/10/day-two-of-building-my-mt-box.html
It shows how the LEDs are set up. Dont use LEDs in the 940nm wavelength since wecams have a hard time of seeing that wavelength compared to the 850nm that I am using. They are all powered using a laptop power supply.
Hey Peau, is that a series circuit you have there for the leds?
ReplyDeletelooks like a series circuit to me. Where are your resistors? How big is the voltage of the power source you used?
ReplyDeletesheley at the top right of my blog here are two links to LED calculators that help you out in figuring out how to make the wiring sircuit. My circuit is 4 parallel circuits, each composed of LEDs in series with a resistor on the end, all hooked up to a laptop power supply (which is a really nice and usually inexpensive way to get a power adapter. I spent $20 for a knockoff brand one). The power supply I think runs at 18.9vts or so.
ReplyDeleteIve been working on making a multitouch display and I came across your tutorial on youtube. So I'd bought two PS3 eye cameras. When I opened up the first one, I it took me two hours to dig out what I thought was the IR filter. As it turns out, that PS3 eye wasn't made with an IR filter. What I had dug out was a part of the lense thinking that it was the filter. Here is a photo diagram of my experiment.
ReplyDeletehttp://www.particle9productions.com/downloads/ps3eye.jpg
So when I put the lense back to the board and plugged it in all I got was a big blob. Thinking this is definately not right, I plugged in the 2nd brand new PS3 eye, shined a few different remote controls with IR LED's into it. the unmodified PS3 eye saw the IR light just fine. So I taped a piece of floppy to the outside of the lense and wa-la! an IR camera with a bandpass. didnt even have to open it up. So Im wondering if Sony has decided to drop the IR filter out of the cameras. Just thought I would share.
I forgot to mention, That was the first piece of glass inside the lense. There was nothing else that looked like the IR filter that you dug out of your cameras in the videos. What I pulled out was the first piece of glass that I saw when I pulled off the lense housing.
ReplyDelete