Detecting Laser Diode?

For other supported Arduino products from Adafruit: Shields, accessories, etc.

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
Locked
User avatar
ibucky
 
Posts: 112
Joined: Wed Jan 11, 2012 10:40 pm

Detecting Laser Diode?

Post by ibucky »

I'm going to make a Laser maze with a couple lasers, mirrors and a photo cell to sense if the laser has been broken.

My question is - can I use the Photo cell (CdS photoresistor) to detect the laser light or will the laser burn the photoresistor out? If not the Photo cell what can I use to sense the laser light?

User avatar
adafruit_support_mike
 
Posts: 67454
Joined: Thu Feb 11, 2010 2:51 pm

Re: Detecting Laser Diode?

Post by adafruit_support_mike »

If you stick to class-1 lasers (the average cheap laser pointer), you shouldn't have any problems. Those don't have enough power to damage a human eye with extended exposure, even when run through a focusing lens, so they shouldn't hurt a photosensor.

As for sensors, you have a range of options. A CdS photoresistor will work, but so will photodiodes, phototransistors, and the everyday red LED. CdS is losing popularity because it's toxic, so I'd suggest going with silicon unless you already have the CdS on hand.

Silicon devices will definitely stand up to a laser because they use the photoelectric effect. All silicon devices are photosensitive, and sensors are just designed to take the best advantage of it. LEDs make decent sensors because the math works both ways.. putting current through the junction generates light, and putting light into the junction generates currrent. They work best for wavelengths close to the ones they emit, so if you have a red laser pointer, try shining it on a red LED and see what kind of response you get.

User avatar
ibucky
 
Posts: 112
Joined: Wed Jan 11, 2012 10:40 pm

Re: Detecting Laser Diode?

Post by ibucky »

Thank you for the suggestion on the LEDs - I'm going to try that! Didn't think of it in reverse - very nice.

Locked
Please be positive and constructive with your questions and comments.

Return to “Other Arduino products from Adafruit”