1 of 2
1
My DI Multi-touch Table
Posted: 29 July 2009 03:56 PM   [ Ignore ]
Avatar
Rank
Joined  2009-05-15
Total Posts:  54
New Member

Hey everyone!

After several months, I’ve decided to finally buckle down and build a multi-touch table!
I’ll be posting my progress in this thread (along with lots of photos) smile

Type of Table: Rear DI
Screen Size: 38” 4:3 screen (approximate)
Actual Table Dimensions: To be decided

PARTS ORDERED: (All Prices are in CAD)
RECEIVED Projector (BenQ MP522ST) / Cost: $723.21
RECEIVED PS3 Eye / Cost: $42
ORDERED New Lens/Mount for PS3 Eye: $23.29
RECEIVED IR Filter for PS3 Eye / Cost: $24.58
RECEIVED Infrared Illuminators (4) / Cost: $80.41
RECEIVED First Surface Mirrors (2) (16” X 11-1/2") / Cost: $26.81
ORDERED 320 GB External Hard Drive (For Windows 7) / Cost: $69.36
RECEIVED Aluminum Foil / Cost: $3.12
RECEIVED Power Plugs for Infrared Lights / Cost: $12.58
RECEIVED Casters (4) / Cost: $12.10
RECEIVED 1/2” Pine Plywood (2) / Cost: $69.45
RECEIVED 1x4x12 Strapping / Cost: $4.69
RECEIVED 946 ML Primer (paint) / Cost: $12.74
RECEIVED Deep Onyx Paint / Cost: $19.15
RECEIVED Paintbrush + Tray / Cost: $7.31
RECEIVED 24 volt fans (2) / Cost: $40
RECEIVED Screws, Braces, Glue / Cost: $7.65
ORDERED 31” x 24” one-side sandblasted glass / Budget: $70

Total Spent: $1,179.45
Total Estimated: $1,248.45

COMPUTER SPECS:
CPU: 2.66 GHz Core 2 Duo E7300, 1066 MHz FSB
RAM: 2.00 GB 800mhz
Graphics: 512MB Sapphire Radeon HD 4650

--

UPDATE: I now nearly have all the parts. Just need to receive the acrylic (ordered it from a local shop), my extra hard drive, and maybe a few extra parts if I find the need. I’ll be getting started on the building of the table shortly smile

Also, any suggestions / comments are greatly appreciated!

~Dan

 Signature 

Building a Rear DI multi-touch table! link
Click here to view my multi-touch blog!

Profile
 
 
Posted: 29 July 2009 04:03 PM   [ Ignore ]   [ # 1 ]
Avatar
RankRankRankRank
Joined  2007-09-18
Total Posts:  882
Moderator

Good luck , DAn !
Keep focus & be patient .

Maybe you could switch acryl for frosted glass or 7FD006 since even diffuse illumination is the first goal ..

Processor & Ram are ok .

 Signature 

How many touches can you simultaneously perform ? 
Coming soon : EveryWall MT / Multi LaserPointers / MT SMS Wall
le WIKI en Français

Profile
 
 
Posted: 29 July 2009 04:07 PM   [ Ignore ]   [ # 2 ]
Avatar
RankRankRankRankRankRank
Joined  2009-04-14
Total Posts:  1897
Dedicated

Hi,
I’m working on a Rear DI setup too, which is quite finish now…
Here are the little advices I would give you for your table :
- I’m using 6 IR illuminators for a 23” screen, and I think you should go for 8 as your screen is bigger… 4 is ok, but 6-8 is better if you’re planning to use your table with a normal ambiant light.
- I see you’ve planned to use tracing paper as projection surface. That was my first projection surface too, with no acrylic but glass. You should considering frosted glass… I’m using frosted glass on one side since this afternoon, I’m not done with my tests, but it is really better than tracing paper… Brighter and finger detection is more accurate, and image precision is now good enough if I wanna use fiducials.
- For your pc, 2GB is engouh if you’re not planning any tough games… (i’m using 4GB in x32, so 3.25). The most important thing is to think that ccv uses a lot of CPU, almost 30% of mine is used for finger detection and all that stuff…

 Signature 

One more but very useful blog : http://blog.cktouch.com/
Rear DI + Windows Seven = So Nice…
_________________________________________________

Profile
 
 
Posted: 29 July 2009 04:13 PM   [ Ignore ]   [ # 3 ]
Avatar
Rank
Joined  2009-05-15
Total Posts:  54
New Member
MashineGun - 29 July 2009 04:07 PM

Hi,
I’m working on a Rear DI setup too, which is quite finish now…
Here are the little advices I would give you for your table :
- I’m using 6 IR illuminators for a 23” screen, and I think you should go for 8 as your screen is bigger… 4 is ok, but 6-8 is better if you’re planning to use your table with a normal ambiant light.
- I see you’ve planned to use tracing paper as projection surface. That was my first projection surface too, with no acrylic but glass. You should considering frosted glass… I’m using frosted glass on one side since this afternoon, I’m not done with my tests, but it is really better than tracing paper… Brighter and finger detection is more accurate, and image precision is now good enough if I wanna use fiducials.
- For your pc, 2GB is engouh if you’re not planning any tough games… (i’m using 4GB in x32, so 3.25). The most important thing is to think that ccv uses a lot of CPU, almost 30% of mine is used for finger detection and all that stuff…

Alright, so with the frosted glass, you just have the bottom side frosted? And then you don’t need tracing paper?
Could I get the exact type/brand of glass that you used?

Edit: What about frosted acrylic?

 Signature 

Building a Rear DI multi-touch table! link
Click here to view my multi-touch blog!

Profile
 
 
Posted: 29 July 2009 05:18 PM   [ Ignore ]   [ # 4 ]
Avatar
RankRankRankRankRankRank
Joined  2009-04-14
Total Posts:  1897
Dedicated

Exactly, the bottom side is frosted, no need for tracing paper at all.
The glass sheet was made by a friend of mine so I dont know the type, but it is 5mm thickness, sand frosted… (there is also acid frosted, I have a sample, but doesnt seem better than sand frosted).

I have a very small sample of frosted acrylic but nothing enough to give it a real try. I didn’t pick acrylic because I wanted the glass to be solid because I’m bulding a coffe table for daily use as well…

 Signature 

One more but very useful blog : http://blog.cktouch.com/
Rear DI + Windows Seven = So Nice…
_________________________________________________

Profile
 
 
Posted: 29 July 2009 05:23 PM   [ Ignore ]   [ # 5 ]
Avatar
Rank
Joined  2009-05-15
Total Posts:  54
New Member
MashineGun - 29 July 2009 05:18 PM

Exactly, the bottom side is frosted, no need for tracing paper at all.
The glass sheet was made by a friend of mine so I dont know the type, but it is 5mm thickness, sand frosted… (there is also acid frosted, I have a sample, but doesnt seem better than sand frosted).

I have a very small sample of frosted acrylic but nothing enough to give it a real try. I didn’t pick acrylic because I wanted the glass to be solid because I’m bulding a coffe table for daily use as well…

Alright smile
So how does it look compared to using clear acrylic/glass with tracing paper? Is the quality better or worse?

Also...would buying clear acrylic and then painting this on (link) work? (It’s designed to be painted on to acrylic).
For example, would it let the IR light through still?

Thanks!!

 Signature 

Building a Rear DI multi-touch table! link
Click here to view my multi-touch blog!

Profile
 
 
Posted: 29 July 2009 05:27 PM   [ Ignore ]   [ # 6 ]
Avatar
RankRankRankRankRankRank
Joined  2009-04-14
Total Posts:  1897
Dedicated

Well there is two thing to consider : the quality of the image and the quality of the finger detection : as for the quality of the image, it is brighter with the frosted glass, and the grain is better, but a little bit of an hotspot phenomenom, but very discret. As for the finger detection, no comparaison possible, the frosted glass is a real advantage. This is why you should really consider the frosted glass…

I’ve never heard of this paint so I cant help you… You should try to contact the compagny directly and explain them your dilema…

 Signature 

One more but very useful blog : http://blog.cktouch.com/
Rear DI + Windows Seven = So Nice…
_________________________________________________

Profile
 
 
Posted: 29 July 2009 05:35 PM   [ Ignore ]   [ # 7 ]
Avatar
Rank
Joined  2009-05-15
Total Posts:  54
New Member
MashineGun - 29 July 2009 05:27 PM

Well there is two thing to consider : the quality of the image and the quality of the finger detection : as for the quality of the image, it is brighter with the frosted glass, and the grain is better, but a little bit of an hotspot phenomenom, but very discret. As for the finger detection, no comparaison possible, the frosted glass is a real advantage. This is why you should really consider the frosted glass…

I’ve never heard of this paint so I cant help you… You should try to contact the compagny directly and explain them your dilema…

Alright, I’ll go with the frosted glass then smile
Hopefully I can find a place that will do it fairly cheap.

Thanks again!

 Signature 

Building a Rear DI multi-touch table! link
Click here to view my multi-touch blog!

Profile
 
 
Posted: 29 July 2009 05:38 PM   [ Ignore ]   [ # 8 ]
Avatar
RankRankRankRankRankRank
Joined  2009-04-14
Total Posts:  1897
Dedicated

it is more expensive then tracing paper but I’m going to stick with it… mine cost 90€/m²

 Signature 

One more but very useful blog : http://blog.cktouch.com/
Rear DI + Windows Seven = So Nice…
_________________________________________________

Profile
 
 
Posted: 29 July 2009 11:06 PM   [ Ignore ]   [ # 9 ]
Avatar
Rank
Joined  2008-11-11
Total Posts:  80
New Member

Hi!

Tomorrow I’ll try a piece of frosted glass; as said MachineGun, it seems that frosted glass it’s a good option; now I’m trying with cortain shower plastic, and I got:

image quality: very good, no projector hotspot, good contrast too
blob detection quality: not so good; better finger detection when plastic it’s over the acrylic (finger close to diffuser it’s better, as I read), but more even surface illumination when it’s below the acrylic. And you have to deal with how to keep a tight plastic.
feel (touch) quality: if cortain shower plastic it’s used over the acrylic, it feels better than just touch the acrylic, but as I read, I think it’s better rosco grey sensation. About this, in Chile there is no supplier of Rosco Grey (there are agents, but they don’t have this product specifically); do you know some supplier who send to worldwide?

I’ll post when I got results with frosted glass

cheers (salud!)

*I’m using acrylic, because soon I’ll try FTIR

 Signature 

Rear DI, in progress: http://nuigroup.com/forums/viewthread/6571/

Profile
 
 
Posted: 30 July 2009 02:59 AM   [ Ignore ]   [ # 10 ]
Avatar
RankRankRankRankRankRank
Joined  2009-04-14
Total Posts:  1897
Dedicated

waiting to see your results, I’ll do some videos as soon as possible (within the next week, I promise).
as I said, the frosted glass is for me very powerful for blob detection quality, and it allows the use of fiducials, even with the frosted side on the bottom. And when I speak of an hotspot, it is very light, all the image is brighter than with tracing paper.

 Signature 

One more but very useful blog : http://blog.cktouch.com/
Rear DI + Windows Seven = So Nice…
_________________________________________________

Profile
 
 
Posted: 30 July 2009 06:26 AM   [ Ignore ]   [ # 11 ]
Avatar
RankRankRankRank
Joined  2008-01-04
Total Posts:  676
Moderator

Hey guys, I’m looking forward to seeing some vids too wink

 Signature 

Get Sparked at sparkon.net
ORION Multi-Touch Display (blog)
My YouTube

Profile
 
 
Posted: 30 July 2009 06:44 AM   [ Ignore ]   [ # 12 ]
Avatar
RankRankRankRankRankRank
Joined  2009-04-14
Total Posts:  1897
Dedicated
Fairlane - 30 July 2009 06:26 AM

Hey guys, I’m looking forward to seeing some vids too wink

your advices on frosted glass were very useful, and I’m very satisfied of this solution… tks
I’ll post some new videos, soon

 Signature 

One more but very useful blog : http://blog.cktouch.com/
Rear DI + Windows Seven = So Nice…
_________________________________________________

Profile
 
 
Posted: 31 July 2009 02:16 AM   [ Ignore ]   [ # 13 ]
Avatar
Rank
Joined  2008-11-11
Total Posts:  80
New Member

Hi!

QUICK test about cortain shower plastic v/s frosted glass (cortain shower plastic OVER acrylic 8mm)

image quality: in this first quick test, I saw better contrast, bright and diffusion with the plastic; bright and contrast with frosted glass it was weack. With the plastic there is no projector hotspot.
blob detection quality: I can’t say something reliable, because I dont’ get yet a good diffused illuminaton (I’m using 4 IR lamps with 42 IR LEDS 850[nm]) and 2 normal mirrors; with this it’s dificult to find the right angles and direction for the lamps) <-- help with this please smile
touch feeling quality: it’s feels better touch plastic than just acrylic; it happens something similar with frosted glass, it’s feels better to touch the frosted side, especially for drag.

I have read that there is grades of grain/frosted for the frosted glass, maybe this it wasn’t with “enough grain”

Sorry the bad quality of videos (they was recorded with a very cheap camera, I forgot the good one rasberry)
For a visual comparison:

Here the ‘drag comparison’:

Here ‘behind the scenes’:

attached pictures of what PS3 sees

comments are very welcome wink

P.D.: where to buy Rosco Grey with shipping worlwide?

Image Attachments
cap01.jpg
 Signature 

Rear DI, in progress: http://nuigroup.com/forums/viewthread/6571/

Profile
 
 
Posted: 31 July 2009 03:50 AM   [ Ignore ]   [ # 14 ]
Avatar
RankRankRankRank
Joined  2008-01-04
Total Posts:  676
Moderator

Nice Vids Fernando, I fixed your YouTube links… Edit your post to see how I fixed them so it might help you to do it next time… wink
I used sandblasted glass for my setup as a diffuser/projection surface. (see my blog for details in the How-To section)

MashineGun - 30 July 2009 06:44 AM

Fairlane - 30 July 2009 06:26 AM
Hey guys, I’m looking forward to seeing some vids too wink

your advices on frosted glass were very useful, and I’m very satisfied of this solution… tks
I’ll post some new videos, soon

Thanks MashineGun, glad it helped wink

 Signature 

Get Sparked at sparkon.net
ORION Multi-Touch Display (blog)
My YouTube

Profile
 
 
Posted: 31 July 2009 12:23 PM   [ Ignore ]   [ # 15 ]
Avatar
RankRankRankRankRankRank
Joined  2009-04-14
Total Posts:  1897
Dedicated

I’m also using sandblasted glass for my setup, but there is almost no grain, a friend of mine did it so he new that i needed the best quality. He gave me a sample of acid frosted glass but I cant see the difference with sand blasted frosted galss…
I’ll do some nice video with a cam recorder as soon as possible this week…

 Signature 

One more but very useful blog : http://blog.cktouch.com/
Rear DI + Windows Seven = So Nice…
_________________________________________________

Profile
 
 
   
1 of 2
1