Step 11: Installing the Cameras

Three PT Grey Firefly MV (Firewire version) cameras are used in the MT-50 to track the finger movements on the table surface. The cameras come in a small plastic case with a mount assembly. Before mounting the cameras, they need to be taken apart to install the band pass filter.

Remove the case of the cameras to reveal a small circuit board.

There will be a lens mount attached to the board by two screws. Remove the lens mount to reveal a rubber grommet and a small clear lens. You will also see the small CMOS sensor in the middle of the board. This is essentially the ‘lens’ of the camera, so be sure not to allow anything to come into contact with it.

Remove the rubber grommet, and take out the clear lens. Replace the clear lens with the band pass filter. Reassemble the camera.

Once the plastic case is back together, you can then put on the camera lens, and attach the mounting hardware.

Use a 20 x 20 gusset to attach each camera to the camera rig. You will need to drill out one side of the gusset with a ¼” drill bit to enable it to fit the camera screw hole. Using a rubber washer to prevent the gusset from damaging the side of the camera, screw the gusset onto the camera with an M6 screw. Put a screw with 20 mm T-nut into the other side of the gusset and screw the camera to the rig.

Camera spacing is very important to ensure stitching and may need to be adjusted once the tracking software is installed. See the attached diagram to get an idea of the rough spacing that should be used if using a 3-camera system. 

The cameras are powered and controlled via FireWire. When the camera feed is cropped within the tracking software, it actually communicates with the camera's BIOS and tells it to ignore those extraneous pixels, making the processing very stable and lowering the amount of bandwidth needed to run the cameras. The middle camera runs on its own Firewire card, since it has a larger area to monitor, and the outer two share one, ensuring that the camera feed won't exceed the available bandwidth, which can cause the OS to throw a stop code (Blue screen of death) and force the computer to be restarted.
<p>Hi there, it me again. After apply every thing, i got blobs of my fingers. But there is a serious problem: the movement image on the screen ( white images) also create blobs which cause everything went crazy. Can you give me some suggest to fix this problem. Thanks you again!</p>
<p>Can anyone tell me which kind of rear film that you use? I found that there are several kind which are transparent, dark, gray, .... Which one should be the best for this project? And you also can tell me the website to buy it? Thanks very much!!! I really need this.</p>
<p>Hello MrMap, the rear film used in these systems was SpyeSmoke by Spyeglass. This film worked out great to reduce projector hot spotting - which could occur with the very short throw range of the projector and the first surface mirror. The folks at Spyeglass are great and are very knowledgeable - there may be a newer film that works even better than the SpyeSmoke by now. www.spyeglass.com</p>
How much does it all cost? Sorry, I do not have the time to open each link and add accordingly.
<p>well...thanks...i built it and it cost </p>
<p>I'm sorry we didn't get back to you sooner! I hope your project came along, we'd love to see what you've come up with. We have not built any projection based hardware for quite a while, and the pricing has likely changed quite a bit. The components are also probably out of date, so many of the electronics would likely need to be changed to something current.</p>
Technocraz.Thanks for your question. The software shown in the video was built with the GestureWorks multitouch software framwork. http://www.gestureworks.com
What about the Software? Was it omni touch at that time of your video? Thx
Camtron. It has been some time since we priced all of the components. The aluminum material is fairly pricey. The project materials would cost between $7-$9K. A lot of folks have moved over to IR touch overlays since they are less expensive and you can use an LCD display instead of a projector (PQLabs is a manufacturer.) There are a number of differences, to numerous to go into, but that might be a more cost effective solution.
I am in the Civil Air Patrol and would love to build this for our office. About how much money dose this project cost all together. <br>Thank you <br>Don
Are you trolling? Almost every military branch has this stuff in the US!
um, no. No they dont <br>
I was wondering if you could provide more details about the glass used. Do you know the supplier? Or, do you know the specs used to order the glass with the micro-etching? I work for a glass company, and could conceivably have it re-created (unless we happened to supply it in the first place...) :)
We used an acid etched glass from Sevasa from their HPT series. The glass thickness on this particular unit was 10mm thick. You can check it out here: http://www.sevasa.com/en/technologics-2/products/electronics <br>
Wow, very nicely documented. I also have to commend the company for not only opening this up for the Open Exhibits initiative but to go over and above that and create such a solid Instructable is amazing. Well done. <br> <br>One question. In looking at the PT Grey Firefly cameras I notice that the Instructable doesn't say anywhere that I can find which version of that camera is used. There are over a dozen configuration for that camera. <br>In looking at the data sheet and comparing it to the Instructable I was able to narrow it down to the model FFMV-03M2M/C series but I'd like to know for sure. Also would it be the B/W or the Colour version? <br> <br>Anyway, thanks again for posting.
You were correct on the camera, it is the FFMV-03M2M-CS. We used the B/W version. These cameras are Firewire based, but PT grey and computer hardware in general has changed quite a bit since we were producing these - there may be faster alternatives out there now (as far as frame rate go). Thank you for checking out our Instructable!
thank you!
So cool that you make this available for everyone. Great work.
I love it! Looks very sleek. Good job!
ow nice job might send a link to freind of mine hey could i make this into a desk
Very informative instructable. But if you don't mind me asking, how much would this multitouch rig approximately cost?<br>
The price with the parts listed at the time the table was being produced was between 12-16k. We sourced and used the toughest materials available. <br><br>There are many interchangeable parts within the system that can be purchased for less. You can find some of these throughout the instructable.
VERY NICE!!!! I would of liked more pictures of the finished project.
Here are a few more pictures of the completed table. You might also want to look at our Flickr page (flickr/ideum) as a number of our recent exhibits featured the MT50 multitouch table.

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