Laser safety with no lid. - diyAudio
Go Back   Home > Forums > Source & Line > Digital Source

Digital Source Digital Players and Recorders: CD , SACD , Tape, Memory Card, etc.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 12th August 2011, 09:20 PM   #1
joe58 is offline joe58  United Kingdom
diyAudio Member
 
Join Date: Dec 2009
Location: England
Default Laser safety with no lid.

Hello

Basically have a cd Walkman from a friend and I want to rebuild it into a new case with other features. However I want to do it without the lid(although there may be a acrylic cover) and just have it spinning open.

What are the safety concerns with this, as I have seen other diy-ers do it before. Although an old Philips glass topped Mini Hifi had a silver foil section where the laser was and the lid is always closed when 'play' is pressed and have seen others like this.

My basic questions are; what does the laser shine through? Does it stop say at a 'sticker' I could put on the acrylic lid. Does the laser 'shine' through the cd?

Better safe than sorry.

Thanks

Last edited by joe58; 12th August 2011 at 09:25 PM.
  Reply With Quote
Old 13th August 2011, 01:36 AM   #2
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
It will "shine" in somebody eye if you don't have a CD in, don't have a cover on and press play...
  Reply With Quote
Old 13th August 2011, 01:44 AM   #3
diyAudio Member
 
theAnonymous1's Avatar
 
Join Date: Feb 2004
Location: Anonymityville
I don't think it's that much of a concern really. I played around plenty with CDP lasers when I was younger and never went blind.

They are low power Class-I lasers and the focal length is only a few mm.

Laser Safety

Quote:
Class I laser products produce no accessible laser emissions. For example, a CD player or DVD player/recorder contains an internal laser to read or write data, but does not actually emit any laser light. Products of this type are Class I laser systems. Class I lasers products present no hazard at all unless they are disassembled to gain access to the internal components.
  Reply With Quote
Old 13th August 2011, 03:03 AM   #4
imix500 is offline imix500  United States
diyAudio Member
 
imix500's Avatar
 
Join Date: Mar 2004
Location: Nashville, TN
I agree, with the optics the divergence makes it a non issue at a couple inches or so. You would have to stare directly at a class I laser for a very long time without blinking to do any sort of damage.
  Reply With Quote
Old 13th August 2011, 06:26 AM   #5
diyAudio Member
 
Join Date: Nov 2009
Location: Los Angeles
Isn't the usual startup ?
1:Laser on
2:attempt focus. No focus=stop
3:spin disc. No data=stop
4:Play

Since the disc is nearly opaque I don't see a problem. The light is only concentrated at the focal point and the beam diverges a lot to not see surface dust. Still it would be better to cover it and protect the optical block.
  Reply With Quote
Old 13th August 2011, 09:03 AM   #6
joe58 is offline joe58  United Kingdom
diyAudio Member
 
Join Date: Dec 2009
Location: England
When your talking about the length is that the wavelength or the actual length the laser 'shines' up to and runs out of power and 'stops'?

Also I didn't know if the disks were quite opaque as when I've looked through discs before I've been able to see the cover art sticker. Also is it a visible laser like infrared?

Another thing I've thought of is that a walkman doesn't auto close the lid, so you may be able to press play with the lid open and no disc? I will try and test this, although they're may be a mechanism/ procedure to stop this.

And this is the link from the other post: http://www.homebuilthifi.com/project/204

Last edited by joe58; 13th August 2011 at 09:07 AM.
  Reply With Quote
Old 13th August 2011, 01:30 PM   #7
diyAudio Member
 
Join Date: Jan 2008
Location: Virginia
The lid has a microswitch to "tell" the controller that it is closed.
  Reply With Quote
Old 13th August 2011, 02:15 PM   #8
joe58 is offline joe58  United Kingdom
diyAudio Member
 
Join Date: Dec 2009
Location: England
I also remember seeing this, which is all over the web. It doesn't have anything in the way of stopping you not putting the cd in and playing and therefore activating the laser from what I can see. Is it safe? Not an area of expertise as the only stuff I know about laser etc is what is in a A-level. And rather be safe than sorry.

link: Make a Muji Wall Mounted CD Player | VVANK
  Reply With Quote
Old 13th August 2011, 02:20 PM   #9
Mooly is offline Mooly  United Kingdom
diyAudio Moderator
 
Mooly's Avatar
 
Join Date: Sep 2007
Remember most of the energy from the laser is in the near infra-red so your eyes don't register it as visible but it still passes into the eye and can conceivably do damage particularly if viewed close too. If you could see it, it would be dazzlingly bright.

All the comments re focal length are correct but it's better to be safe than sorry...
__________________
-------------------------------------------------------
Installing and using LTspice. From beginner to advanced.
  Reply With Quote
Old 14th August 2011, 08:46 PM   #10
joe58 is offline joe58  United Kingdom
diyAudio Member
 
Join Date: Dec 2009
Location: England
Information taken from laser marking company. Link.

CLASS I

Class I lasers are low powered devices that are considered safe from all potential hazards. Some examples of Class I laser use are: laser printers, CD players, etc. No individual, regardless of exposure conditions to the eyes or skin, would be expected to be injured by a Class I laser.

Then on class 2 they talk about they are harmful and if pointed in someone eyes it can cause damage. However on another site it tells me that higher power lasers can also be classified as class 1, but built so as no contact can come into the laser beam with an example being cd players, which I take as being the lid and the microswitch. Plus on the bottom of the player it tells me that radiation can occur if interlock defeated and lid open.

Therefore I won't bother and make something with a little more protection. I still don't know how the other open cd players do it and how damaging it could be, but I will not risk it as I need my eyes for jobs I want in the future. What's a designer with no eyes... Thanks for the comments and help above.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Planar 3 lid design berthej Analogue Source 10 8th March 2007 08:17 AM
Want: Cyrus Lid richie00boy Swap Meet 0 27th April 2005 01:39 PM
So, can I run a Hafler DH-500 without the lid? Bogie Solid State 4 31st December 2004 08:43 AM
Suggestions for lid material analog_sa Chip Amps 17 3rd September 2003 10:37 AM


New To Site? Need Help?

All times are GMT. The time now is 11:18 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2