Need some helps about laser pointer and photocell

[TechySafi]

Fist of all sorry for my bad English skill

Question 1: Can anyone tell me which type laser pointer is most suitable for daylight+nightime (works well in both situation)??

Question 2 :Same question(like question number 1) for photocell switch.

Question 3: How can I measure which laser and which photocell switch will work for a long distance?? Let me make this question clear...suppose if you give me 2 piece of resistor of 5KΩ and 10KΩ and ask me which resistor have more resistance?? I can easily answer this question because I know where to look (that is Ω)...but in case of laser I have no idea which data tells what.

So kindly take a example data of a laser pointer and explain me which means what.


Question 4: Again same question (like question number 3) for a photocell switch.

Question 5: If someone cross the laser beam (imagine a thief) how rapidly the targeted photocell switch start working?? Let me explain it, imagine you crossed the laser and so Photocell switch make complete the circuit and a hidden camera takes a photo. So I need to know how rapidly the switch can work to take the thiefs photo properly before the thief runs away out of the focus of the camera.

I know you will have a little trouble to understand my all questions but please please help me. Im a boy of Grade 10 and I want to apply this trick to capture a photo of those the vehicle's numberplate who don't obey the traffic signals I think its gonna be a fun in next science fair.

Thanks in advance
TechySafi

 

[Dr_Doggy]

you wont need to worry about timing too much since both light and electricity both go fast enough

if you are making a "trip line" any laser will do pretty much, unless you go up to like a half mile, you may want to use a more powerful one (5mW)

instead of using a photo resistor, id recommend a photo transistor, you can then get one to filter colors except for the lasers color, resistors vary values, while a transistor is more like a switch

Light is measured in Lumens and Lux, you can read up but you wont need it much for this.

Hard part for you is going to hook the sensors up to the camera button, a relay may easiest for you, unless you know how to use transistors,

 

[TechySafi]

Thanks man....you well answered my all questions....

Hey can you give me some extra info about photo transistors??

Yeah, switching the camera is the hardest part to me...you said "a relay may easiest for you, unless you know how to use transistors" can you explain it a little more?? Or any source??(links)

Again many many thanks for the reply!!!

 

[Dr_Doggy]

actually i think you may get away with this...:

1)open camera, read voltage on each side of button, put ground lead on battery ground
2) hook sensor power to live wire on button, hook sensor output on other wire of button, hook sensor ground to battery ground

 

[TechySafi]

Hey, I changed my plan....I think there is no hard N fast rule that I must have to use a digital camera, since its a school level science fair. So now I want to use only a flash light instead of a camera (this flash light will act on behalf of a camera). And cameras are too costly also so I can't use them since there are some risk of being damaged.

So whats the simplest way to flash up the flash light each time the laser beam is broken?? Here's a image, is it perfect??