405nm safety questions

[tuckerPi]

Hi everyone,

I'm new to the forum and came here to learn.

I've recently made a laser gimbal device that "draws" with a 405nm 5mw laser pointer I bought on ebay.
Ebay Listing

Here's a video of my application
YouTube Video

So my questions are:

1) Do you think I need to be wearing safety glasses while my robots draws?

2) Is there anything I can do to make it so the user doesn't need glasses? Such as adding a filter or decreasing power?

3) If it is dangerous can I lower the input voltage to get the output power into a safer range?

4) Is there any other ways to "write" on a surface with a laser that would be safer?



It say class 2 laser on the sticker but I'm guessing its probably not...

 

[Alien Laser]

Welcome to LPF
, I recommend using safety glasses even if its 1mW that's just me op:
--> The is a search button on the right corner use it

 

[paul1598419]

That laser is likely in the 40 to 80 mW range. As long as the only thing it is pointed at is the fluorescent screen, you are probably okay. However, if it can be reflected back to you, it is far more powerful than it looks and could be an eye hazard.

 

[Razako]

That laser is likely in the 40 to 80 mW range. As long as the only thing it is pointed at is the fluorescent screen, you are probably okay. However, if it can be reflected back to you, it is far more powerful than it looks and could be an eye hazard.

Gonna agree with this.

 

[tuckerPi]

That laser is likely in the 40 to 80 mW range. As long as the only thing it is pointed at is the fluorescent screen, you are probably okay. However, if it can be reflected back to you, it is far more powerful than it looks and could be an eye hazard.

It does have a light purple reflection dot that bounces back. I'm guessing thats probably enough for me to want to have glasses on for.

I'm wondering if I could find a non-reflective surface or somehow lower the power to prevent the need for safety glasses.

Until I can find a safe solution I'm going to find some safety glasses to buy

 

[paul1598419]

If it reflects a light violet dot that you can see, the screen must be very reflective itself. That is quite unusual for a fluorescent screen.

 

[tuckerPi]

If it reflects a light violet dot that you can see, the screen must be very reflective itself. That is quite unusual for a fluorescent screen.

Ya it has a visible purple dot reflection. Its a glow in the dark sticker sheet with a glossy surface.

 

[paul1598419]

I would see about placing it with a nonreflective screen. That is just dangerous.

 

[tuckerPi]

I would see about placing it with a nonreflective screen. That is just dangerous.

Thank you and good point. I couldn't find any non-reflective glow sheets though.

I think I'll buy some high quality glow paint (which should glow much brighter even using a lower powered laser) and paint it on printer paper. That way it should be a non-reflective surface.

Then I'll drop the voltage input of the laser (currently at 3.5v) to some lower voltage that allows the laser to be just bright enough to illuminate the glow paint but not reflect.

Hopefully then it will be safe to operate without the need for glasses. Do you think this will be safe enough?

I'm also curious if there is another way to "write" on a surface and have it glow and fade. If I can accomplish the same effect with a more safe wavelength than I would much rather do that. I've heard green lasers can illuminate yellow glow paint?

 

[paul1598419]

Laser drivers are constant current supplies. Dropping the supply voltage shouldn't effect the output until it is so low the driver won't work. So, that is not a good idea for dropping the output of your laser. As long as your surface is not reflective, you should be alright.