Looking for circuit to detect laser light

[eljainc]

Hello,

I'm looking for a simple circuit that will detect light from a red
laser light source (i.e. a laser pointer). Something as simple as
logic 0 or 0V with no light and logic 1 (+5V) with the presence of
laser light.

Thanks.

Mike McWhinney

 

[Charles]

Hello,

I'm looking for a simple circuit that will detect light from a red
laser light source (i.e. a laser pointer). Something as simple as
logic 0 or 0V with no light and logic 1 (+5V) with the presence of
laser light.

Some ideas here: http://home.cogeco.ca/~rpaisley4/8PhotoDetect.html

 

[aalex]

Some ideas here: http://home.cogeco.ca/~rpaisley4/8PhotoDetect.html

You can use a light sensor if you have a ADC input, such as a
microcontroller. You might want to add a red filter. (a gelatine)

a

 

[D from BC]

Hello,

I'm looking for a simple circuit that will detect light from a red
laser light source (i.e. a laser pointer). Something as simple as
logic 0 or 0V with no light and logic 1 (+5V) with the presence of
laser light.

Thanks.

Mike McWhinney

Maybe...
Phototransistor with red lens.
Or
Cds cell with red lens.
Or
Photodiode with red lens.

More off-beat ideas...
Solar panel with red lens.
Thermistor with red lens.

D from BC

 

[Benj]

Maybe...
Phototransistor with red lens.

Sensitive and fast but needs external circuit (see project referenced
above)

Or
Cds cell with red lens.

Works great and sensitive but slow.

Or
Photodiode with red lens.

Also works great but takes more laser light and probably needs some
gain to work well.

More off-beat ideas...
Solar panel with red lens.

Basically same as photodiode but much less sensitive.

Thermistor with red lens.

Going to take to REAL laser power to a response here!!

How about Fairchild QSE-156 photosensor? threshold at 25 mw/cm^2

This sounds like a pretty simple project and the purpose has not been
stated so it's difficult to tell what is needed. For REAL sensitivity
use a photomultiplier tube. And if ambient room light or daylight is a
problem I strongly urge the use of not just a RED filter but rather a
BANDPASS filter set to the laser wavelength. Go check them out at
Edmund Scientific Expensive but worth it. .