Monday, February 23, 2009

PS3 Eye Camera Band Pass Filter Insertion (updated)

**Update 3/20/09: Filters for those looking for 850nm or 880nm are available now that will correct the focus when inserted between the CMOS sensor and the stock lens.
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 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.

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.
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.

Saturday, February 7, 2009

3D Models of Optical-Based MultiTouch Techniques

I have made some 3D models showcasing the current methods to make optical-based multi-touch setups: FTIR, Rear DI, Front DI, DSI, LLP, and LED-LP
They are all done in the game Second Life, which has really good 3D building abilities.
Ive also modeled some MT setups: my current LED-LP, my in-progress DSI, cerupcat’s FTIR, AlexP’s LLP and more to come.
Take a look. I have hopes that the basic modeling will be used as helpful information for learning about MT and how it all works in the hardware side.
And the other picture is of my living room, with my in-progress DSI table as the coffee table. Oh and my art on the walls smile