Looking for some information!

[AdamMortlock]

Hi guys, I am currently studying Product Design and in my final year at University. For my major project I am looking into using lasers for safety reasons (I just need to project laser light 10-15 foot onto the floor)

I was wondering as you guys probably have a great knowledge in this sort of thing I would really appreciate if you could point me into the right direction for the following points;

1. The best kind of lasers to use for a consumer product like this (needs to be energy efficient, yet bright enough to be seem during the day?
2. Can you get lasers that will cast an image into the air at a set distance e.g. 10 feet and then can be seen for a long distance, or does it have to hit something solid to stop?
3. Is there current technology that is available so that as something crosses the laser, the laser notices the 'break' and relays a signal back to the device? (then the device could let the user know about the break in the laser)

thanks for your time guys and hope you can help!

Adam.

 

[NightExplorer96]

Hello there,

I can't answer question 1 and 3 but for question 2:

Can you get lasers that will cast an image into the air at a set distance e.g. 10 feet and then can be seen for a long distance, or does it have to hit something solid to stop?

Well...a laser HAS to hit something so you will see an image, if you just shine a picture into the sky you won't see anything, just light particles. If let's say you hold a piece of paper 10ft in the sky in front of the laser, then yes you will see the picture.

Don't know if that's what you were asking but gave it my best try

 

[AdamMortlock]

Hi, Tha Greenlander,

Thanks to your response to Q2, Unfortunately it confirms what I thought would be the case but thanks for confirming that to me!

Wouldn't it be cool if you could just project something 10-feet into the air in front of you! I guess am talking about a hologram or something out of a movie! haha

 

[NightExplorer96]

Hi, Tha Greenlander,

Thanks to your response to Q2, Unfortunately it confirms what I thought would be the case but thanks for confirming that to me!

Wouldn't it be cool if you could just project something 10-feet into the air in front of you! I guess am talking about a hologram or something out of a movie! haha

It would in fact be pretty nice, maybe even be able to chose the distance we want it projected as?

Well, maybe in the near future if may happen

Hint: Maybe at night if you hold a piece of black paper and hold it up IT MAY LOOK like it a floating picture, but other then that...nope.

 

[AdamMortlock]

Hint: Maybe at night if you hold a piece of black paper and hold it up IT MAY LOOK like it a floating picture, but other then that...nope.[/COLOR]

Unfortunately it would need to be seen from the opposite side that the source is, I think I said that right. I think what I will need to do with this product is just keep it so that it is cast onto the floor.

 

[ryansoh3]

Which part of the laser do you need to be seen, the beam or the dot?

A dot would be easily noticeable on the floor during daylight with a 10mW to 50mW green laser. You should look into some good modules and attach a nice heatsink to it so that it can run continuously. FastTech seems to be selling a good module, and you can get a matching 12mm heatsink mount on ebay.

Check these threads out:

http://laserpointerforums.com/f45/30mw-532nm-fasttech-module-build-82070.html
http://laserpointerforums.com/f45/75mw-fasttech-build-15-a-81268.html

If you're trying to make the beam visible, that's a different story, as you'll need 100mW to 500mW of green laser with fog/smoke. We don't recommend that because it's an eye hazard.
Anything over 5mW is an eye hazard, so please be careful.

Green is the most visible to the human eye compared to other wavelengths, so you should go with 532nm.

As for question 3, check out the laser harp: Tetris Theme on Laser Harp - Theremin Hero LIVE! Finale - Gamecity 5 Nottingham - YouTube

I think the vet here Things sells it.

 

[AdamMortlock]

Thanks Ruansoh3,

I am hoping to do a next generation product of the image above! to improve cycling safety even further by promoting a safe personal cycling environment. Is this kind of thing done via beam or dot? am not sure, can you let me know please haha :yh:

http://www.wired.com/images_blogs/autopia/images/2009/02/03/lightlane_laser.jpg

Link to image if it didnt show on the post ^^

Thanks for the link to that video! exactly what I was looking for, and I believe looking at the comments they use Photosensors so I can do some research into them and hope it can be placed into a small handheld device

 

[ryansoh3]

Ah, I see where you're getting at.

There, fixed the image for you.

That's using a line generator lens to turn the dot into a line.

I'm curious, how will the photodiode be used in that application?

 

[AdamMortlock]

I'm curious, how will the photodiode be used in that application?

Thanks for that information; am i right in thinking;

To get the light line on the floor they are using the dot of a laser and placing a line generator lens on the end of it. Meaning that 10mW to 50mW green laser would do the job? To be seen clearly as a constant image on the floor through the night and in daylight?

you can use a Photodiode that converts the light 'break' into either current or voltage that then power something to make a noise?

Also I want to use it in application so that if something was to break the line a sound relay would be produced so the cyclist knows that something is in very close proximity:yh:

thanks for the ebay link and the fasttech ones and thread links they all gonna help!

 

[AdamMortlock]

Ah, I see where you're getting at.

There, fixed the image for you.

That's using a line generator lens to turn the dot into a line.

I'm curious, how will the photodiode be used in that application?

I got another question also =] Can you have a laser that gives out more then one color without having to have two different lasers? at seperate times, not both colours at the same time.

Adam.

 

[ZRaffleticket]

They exist, called Multiline lasers, some can be tuned to show a specific line at a time... though don't waste your time trying to find them as portable as you may want it.

Your best bet, for multiple colors, is multiple lasers. It's doable with diodes and a PBS cube.

 

[ryansoh3]

I just tested a 70mW green laser module with a line generator lens, and it's very noticeable even in a brightly lit room.

In order to determine whether the laser has been blocked, you'll either need a photodiode at the other side, or use a scanner to get optical feedback. (very complex)

Personally, I think it's very very hard to do either of them with a laser line.

Yes, a PBS cube is what you're looking for. Shoot two different lasers and out comes one beam. You can add a line generator lens in front of that.

 

[AdamMortlock]

Thanks for that guys! With the PBS Cube am looking at them, will the 5mm one do (it has the 420-680nm wavelength range so can get green and red) the trick is this is going to have to fit in a small space, for example the whole unit, with the lasers and everything else needed needs to fit on the seat post or handlebars of a push bike. 5mm PBS = $160 at retail! and would I need to use a beamsplitter adapter? is that available for 5mm PBS?

The problem with these multi-line lasers is they look very, very expensive! (and big) and unfortunately it looks like the photo diode wouldn't work if I need something at the other end of the laser. And I think using a scanner for optical feedback in the daylight or in a city environment could be a nightmare for just a cycling safety accessory.

Ryansoh3, that 70mW you tested, how fast do you think it would get through some batteries? probably lithium AA 2x

 

[ryansoh3]

The 70mW module I tested was green, so it's much brighter than 70mW of red.

A laser over 100mW chews through batteries pretty quickly, I would say a few hours max for 2x lithium AA cells.

Heat would be another issue. Make sure the diode/module and the driver is able to survive that duty cycle. Good luck!

 

[AdamMortlock]

Thanks for all the help Ryan, it's really appreciated!

I will be spending a lot of time looking into it once I get the go-ahead and might end up back in here asking for help again, as long as you guys don;t mind, as you have proved very factual.

thanks,

Adam.

 

[Tmack]

I thought I have seen some light set ups for bike that allow the lights to run off the energy of the bikes spinning wheel. Could that be applied here if battery life is an issue? I can't imagine it would be very cost effective, but if it an idea of concept it might be something to mention.