non light sensing diode??

[shyamgenious]

The subject may have confused what i am about to discuss about but does anybody have an idea how tomake a light sensing diode set out a signal for current to flow when suddenly inturrupted because of not recieving light for a moment??LIKE if directed a laser beam to the diode and if somebody puts his hand in between,the diode stops recieving light momentarily and sends a signal to activate an alarm and makes the person this . any ideas for doing this??
and i have a pen laser light so i also need to know how i can connect it to the mains?? ive made a wall wart to regulate output till 12 volts.

[Soeren]

Hi,

You really ought to search the forum before asking.
(And please reserve the colors and emoticons for where it really helps the post, if anything, it makes your posts harder and quite annoying to read).

[...] does anybody have an idea how tomake a light sensing diode set out a signal for current to flow when suddenly inturrupted because of not recieving light for a moment?

http://www.societyofrobots.com/robotforum/index.php?topic=13076.msg97347#msg97347

and i have a pen laser light so i also need to know how i can connect it to the mains?? ive made a wall wart to regulate output till 12 volts.

http://www.societyofrobots.com/robotforum/index.php?topic=13409.msg99393#msg99393

[hopslink]

...it makes your posts harder and quite annoying to read

It would seem that this is the point of all Shyam's posts.

I suspect garretg84 has sniffed him out.

[Bernhard]

Use a photodiode and an infrared diode config. Something like this...

[Soeren]

Hi,

Use a photodiode and an infrared diode config. Something like this...

That will only do for very a short distance (Won't even cover a doorway).