Laser Trip Mine

This instructable will teach you how to make a laser trip mine.
If someone steps in the lasers path I have gotten it to set off a L.E.D., but you can make it set off other things.

You are going to need:

1. Laser.

2. Photocell, perferably a big one.

3. PNP switching transistor

4. 2 nine volts

5. potentiometer

6. L.E.D

*DONT POINT LASERS INTO PEOPLES OR ANIMALS EYES*

Step 1 The Laser

Attach the laser to the switch and the 9 volt. Make sure everything is compact so that later if you want you can put it in a box. Also to make sure the laser doesnt get burned use a resistor.

Comments

[Dearden805]

So basically when the laser loses contact with the photoresistor it supplies power to the LED? That means you could wire in anything that ran on a nine-volt. Please correct me if I am wrong.

[lukeD]

I have a program for you, Yenka called. it is free if you take the home license. good luck.

LukeD


http://www.yenka.com/en/Free_student_home_licences/

[amruth]

Can someone give me the PNP transistor number like for NPN we have 2N2222 or 2N3904.

[robot1398]

for 2n3904 its 2n3906

[the "wow shammy"]

would a dvd player's laser work?

[GameNox]

Sorry, no. You need a laser BURNER to make it at least cut through paper. I know there has been some confusion about that....

Laser readers like DVD ones read tiny bumps in the CD/DVD. The burner makes those bumps.

[ARJOON]

can i use a laser pointer

[the "wow shammy"]

hard drives contain magnetic reading heads not lasers, right?

[GameNox]

Yeah, I think so.

[techno guy]

Can you make some schematics for this?

[Sparklesam]

I tried hooking this up to a buzzer, but It isn't working at all. Please if anybody has any advice I'd like to know

[Cubie2]

Most buzzers will not just work because they have electricity flowing through them, in fact if you were to open something like say... The Operation game you would find that the buzzer will usually even have a transistor of its own.

[Digy]

 you should try this instructable if you want a buzzer I am building one and it works except it won't stay on when tripped, so I am in the process of finding a different type of transistor.

[rrrmanion]

Google set reset transistor then either get the buzzer to run of the maximum (~5v) or use a relay type thing, to up the voltage

[Digy]

I actually figured out u need a relay to get it to stay on after activation.

[erveli]

How many ohms is the potentiometer?

[coilsinamotor]

is it pnp or npn?? cuz for most switichng applications ppl use npn

[Young Genuis]

Do you need the potentiometer? I can't seem to find one so if it wasn't there I wouldn't mind.

[Digy]

 Yes, it affects the sensitivity of the photocell, basically it is a variable resistor. You can find one at tri-state electronics on northwest highway in mt propect illinois if you around cook county (Chicago-land).

[minerug]

It would be better to get a B216 kit from Jaycar and hook it up to a relay, which in turn is hooked up to a siren or something 

[Colonel88]

Can you post a simple circuit diagram, like maxxxem's but just the bare bones approach?

[maxxxem]

I modded your circuit a little to make LED light or 15 or 30 sec

[Scissorman]

Cool project. What rating is the resistor to protect the laser?

[halo456456]

For my laser, i didnt have to have one. My laser worked on 4.5 volt first so i tried 9 volts and it worked but just as long as you can see the laser on a wall or the photocell the project will work. If the laser is powered with high amps it will burn the photocell and everything it comes in contact with so watch out.

[Colonel88]

that is a waste of energy.

[pyro13]

so how do u raise the amps??!?!?!

[halo456456]

either a transformer or get power with high amps. there is an instructables that tells you how to do that

[pyro13]

ok can u please explain, for a dummy who knows nothing about electronics, how to turn a 5$ lazer pointer from walmart into something that can burn paper with minimal cost.

[jman11]

go to http://daedallasers.com and pick up a blue ray laser diode

[T3Hprogrammer]

1000mA=1A...

[halo456456]

ok, hmmm, have you search the 60$ Laser engraver/ cutter, if you have or dont want to you can take apart an adapter(like a one you plug it a wall, dont shock or kill yourself) that has around 3-6 volts and and 100-450 milliamps(mA= 0.001 so 100 mA equal 1 Amp). The adapter should say how much voltage and amperage it has. Heres a link that can explains it (if the link doesnt work here http://www.felesmagus.com/pages/lasers-howto.html.
hope that helps

[cooter1974]

halo456456, you have same misconceptions about basic electricity/electronics. I'm not saying that to offend you, but to try to get you to do some studying/research (example - 100mA does not equal 1amp, it equals .1amp) You can't take a power source and a fixed load and "increase the amps". You can increase the power source capacity, but it will deliver no more current than the load requires.

[pyro13]

whats it called?

[halo456456]

60$ Laser engraver/cutter" by cgosh

[jman11]

do you think this would work for a multi stage coil gun?

[santy22]

put it into a HL laser tripmine papercraft and it would be VERY COOL

[imakethings]

when the laser beam is tripped will the buzzer ring continuously?

[PKTraceur]

try expresspcb.com they have a PCB maker which you can order from them, and a schematic maker, which I use alll the time. It's free, and awesome. -RoAr

[ian25]

This is how I visualized the schematic. Hope it helps. Great Instructable.

[sdaw]

could you just make a schematic using paint? it would be much easier to understand.