Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: Asellith on April 09, 2008, 08:13:26 AM

Title: VCSEL? What is it and does it have robotics applications
Post by: Asellith on April 09, 2008, 08:13:26 AM
Found This:

http://www.alliedelec.com/Search/ProductDetail.asp?SKU=387-0038&SEARCH=&MPN=OPV322&DESC=OPV322&R=387%2D0038&sid=47E84080514BE17F (http://www.alliedelec.com/Search/ProductDetail.asp?SKU=387-0038&SEARCH=&MPN=OPV322&DESC=OPV322&R=387%2D0038&sid=47E84080514BE17F)

I have read some stuff on VCSELs and I am confused on some stuff. Is this just a cheap laser diode that emits in infrared? It says the wavelength is between 830 and 865 nm and the beam divergence is 6 degrees. So can I use it to do long distance precision range finding or will the fact that it is a laser not let me easily pickup the reflected light? At $5 each if I can find a way to easily detect the light on the robots side I'd like to experiment with them.
Title: Re: VCSEL? What is it and does it have robotics applications
Post by: AndrewM on April 09, 2008, 05:52:02 PM
It looks to be a 1.5mW laser.  On that same page they list some phototransistors etc that will work with it, so I would imagine you could use it as a focused range finder of sorts. 

Now lets get back to the part that it is a laser, and one that is hitting on the infrared spectrum.  A 5mW red laser (around 620nm spectrum) has very little IR bleed out but can still manage to cause eye damage (blind spots).  The more IR a laser gives out, the more you need protective lenses to be around it when in use.  Even though this is a 1.5mW laser, it is high enough in the spectrum that it would not make for a good "being around people" robotic sensor.
Title: Re: VCSEL? What is it and does it have robotics applications
Post by: Asellith on April 10, 2008, 10:31:46 AM
Do the laser range finders use the same type of technology?
Title: Re: VCSEL? What is it and does it have robotics applications
Post by: Steel_monkey on April 10, 2008, 12:04:48 PM
The most dangerous laser is the green one because of eye is most sensitive to green color. IR is not so dangerous because it doesn`t focus straight on retina ( until it is not industrial CO2 "Jedi sword" of course  ;D  ). Another question is that laser is nearly useless in hobby robotics, perhaps only for extremely sensitive contact bumper with multimode fiber ( however, it will not be easy too because of alignment problems ). I was planning to build it, but unfortunately can`t find step-index fiber ( I have access to single mode fiber, graded-index fiber and even microstructured fiber, but not step-index one :D ). Hobby laser rangefinder is a dream.
Title: Re: VCSEL? What is it and does it have robotics applications
Post by: Admin on April 20, 2008, 02:30:48 PM
Im not sure what technology they use for the laser rangefinders, but I'm sure they keep it secret . . .

You definitely need additional specialized electronics to measure the range, its not like a simple emitter-detector pairing that measures intensity.