What model of IR laser diod are you using and where did you get it.

10mw might seem very little compared to a diode, but laser is exact frequecy and its a little more powerfull per mw. I know you are not putting the laser through a lens to focus it, but I would advice that people do not go above 10mw and pref not above 5mw. You need better image add anothe laser diode.  Reason for the limit was given to me on a laser forum by a guy I would consider an expert long explaination but it basically works that as lasers dont spread much and hold most of their power over distance they can damage your eye. he had bunch of maths worked out that explained the enrgy per sqare mm and how it can burn your cornae.
This is admittly not much of a problem for your set up but people should know lasers are not really toys.

Oh yea, MORE ON THIS!
Keep the work up, and creat a new method for MT, just need the technique refined and a name ad it can go in the FAQ.

__
I own a 60W (60,000mw) laser you do not mess with it, it wont burn your retina (frequency thing) but it will burn your corna so I know some thing of what i am gibbering about at 5am

Really Nice Work Alex! Well done again!

What model of IR laser diod are you using and where did you get it?

Sunlight blobs are incredbibles ! Congratulation. I’ll build one based on this model. So robust !

@ szadkowski:
@ Lord Inquisitor:
@ Giggs:

The lasers that I use are all custom made.

Here are the specs:

- 850nm laser diode with 10mW (max power)
- Laser diode power supply circuit (photo-diode feedback LD current control)
- Focusable line with 120° spread using a special non-linear lens (even brightness)
- Variable voltage supply 3.5V-5V

I had a bunch of these modules prefabricated for me, and I have some extra.
If anyone of you is interested, you can have them for $95/each.

~Alex

AlexP - 11 June 2008 01:00 PM

@ szadkowski:
@ Lord Inquisitor:
@ Giggs:

The lasers that I use are all custom made.

Hese are the specs:

- 850nm laser diode with 10mW (max power)
- Laser diode power supply circuit (photo-diode feedback LD current control)
- Focusable line with 120° spread using a special non-linear lens (even brightness)
- Variable voltage supply 3.5V-5V

I had a bunch of these modules prefabricated for me, and I have some extra.
If anyone of you is interested, you can have them for $95/each.

~Alex

You see i live in Kuwait and i have no access to Paypal only international Credit card if you can PM me any online store that sell thous lasers and can deliver to New York because i have a Mailbox there that will ship to Kuwait weekly i will be very grateful

Thanks in advance
Abdullah

Wow, this looks a lot more reliable than LEDs! Isn’t this what MS also did for one of their screens?

As Lord Inquisitor mentioned… please, people, be very very careful when working with lasers. Expecially since you cannot even see the light of an IR laser. If this evolves into a popular method I suggest having bold warnings on all pages about the method. IR LEDs are not that dangerous but lasers certainly are. A lot of people here have absolutely no idea of how even the most basic electronics work. Having this kind of people playing around with invisible lasers that can easily blind you should definitely be something to worry about. We don’t want anybody hurting themselves or others.

That said, this is probably the best method yet. Just remember to put something on the other side of the laser to block the laser from escaping, blinding people who look at the screen from the side.

ALJ - 13 June 2008 06:58 AM

Wow, this looks a lot more reliable than LEDs! Isn’t this what MS also did for one of their screens?

As Lord Inquisitor mentioned… please, people, be very very careful when working with lasers. Expecially since you cannot even see the light of an IR laser. If this evolves into a popular method I suggest having bold warnings on all pages about the method. IR LEDs are not that dangerous but lasers certainly are. A lot of people here have absolutely no idea of how even the most basic electronics work. Having this kind of people playing around with invisible lasers that can easily blind you should definitely be something to worry about. We don’t want anybody hurting themselves or others.

That said, this is probably the best method yet. Just remember to put something on the other side of the laser to block the laser from escaping, blinding people who look at the screen from the side.

Always wear laser safety glasses when working and tuning your table. I got mine here.
Just to note that even though the laser light is focused, by using a line lens, the total power output of the laser is spread along the line. Since the laser light is dispersed, a small section of this line is of a significantly lower power intensity comparing to the full focused dot (without the line lens).

~Alex

cerupcat - 06 June 2008 11:58 AM

Nice post again AlexP! You’re doing great work =)

Would this still have the issue of blocking blobs if fingers are next to eachother since the fingers are only being illuminated from one angle? The other downside that i’d miss is the ability to interpret finger pressure since that can be really important sometimes. Do you think this technique could overcome these obstacles? Like the other techniques, it seems there are definite limitations to this design still.

I think if we could modify the design to incorporate the benefits of the other techniques this would be great. FTIR’s pressure sensitivity, DI’s ability to track fiducials and laser’s ability to send bright output at small wavelengths would be great.

BTW, after looking at the latest touchlib from the svn, it is interesting to note that the code that updates the blob pressure information (blob weight) is commented out and the only thing that is used is the blob area information.

~Alex

Yes, the blob weight/pressure is commented out since we haven’t defined a complete way to interpret the weight and because none of the current applications actually use it. This is only a software issue of course though, not a limitation of the hardware. In the future, pressure will most likely be integrated more into the core of applications (or so we hope). =)

Just a note…

I have my AS3 and WPF reading pressure data… but touchlib does not currently send because commented out…

however I do have an older version of touchlib which sends pressure data… I’ll look around for the source…

AlexP - 11 June 2008 01:00 PM

@ szadkowski:
@ Lord Inquisitor:
@ Giggs:

The lasers that I use are all custom made.

Hese are the specs:

- 850nm laser diode with 10mW (max power)
- Laser diode power supply circuit (photo-diode feedback LD current control)
- Focusable line with 120° spread using a special non-linear lens (even brightness)
- Variable voltage supply 3.5V-5V

I had a bunch of these modules prefabricated for me, and I have some extra.
If anyone of you is interested, you can have them for $95/each.

~Alex

i sent you a PM about this i would love a replay soon

Giggs - 17 June 2008 08:54 AM

AlexP - 11 June 2008 01:00 PM

@ szadkowski:
@ Lord Inquisitor:
@ Giggs:

The lasers that I use are all custom made.

Hese are the specs:

- 850nm laser diode with 10mW (max power)
- Laser diode power supply circuit (photo-diode feedback LD current control)
- Focusable line with 120° spread using a special non-linear lens (even brightness)
- Variable voltage supply 3.5V-5V

I had a bunch of these modules prefabricated for me, and I have some extra.
If anyone of you is interested, you can have them for $95/each.

~Alex

i sent you a PM about this i would love a replay soon

Sorry Giggs, I’ve been swamped… Check your PM.

~Alex

Can you send some pictures of the Lasers you’r willing to sell? And give some dimensions on it?

Project X - 18 June 2008 02:49 PM

Can you send some pictures of the Lasers you’r willing to sell? And give some dimensions on it?

You can see some pictures of the laser I used at the beginning of this thread.
As far as dimensions go here they are: 1.38in x 0.43in x 0.43in

~Alex