Protect Your Home with Laserbeams!

Step 2 Build the Circuit

Build the circuit based on the diagram. I cut my IC board with a dremel to make it smaller so there was enough room in the box along with the 9 v battery.

Comments

[abalachandran]

My brother says the circuit is wrong, is he wright and if he is can someone send me wright circuit plzzzzzzzz . This is my email [e-mail].

[engineer mohammed saber]

this is the correct skematic just swap the led for a realy or buzzer

if you wont the circuit to detect darkness instead swap the ldr and variable resistor places

[dasimpson1981]

this is the correct skematic just swap the led for a realy or buzzer

if you wont the circuit to detect darkness instead swap the ldr and variable resistor places

[steaming punk]

hi, your skematic works well with led or buzzer for example but doesent activate relay for some reason, somebody noted that its AC and for that the realy doesent work. i tried to convert it to DC with four diods but this didnt help either. can somebody please help ?

[dasimpson1981]

have you checked to see if the realy can be triggerd on 9 volts

[steaming punk]

works fine with 9 volts, actually works even from 5 volts

[dasimpson1981]

this was the other circuit i found

[steaming punk]

oh, i just tested out this skematic and it worked fine :), used 5k ohm pot and 2n3904 transistor, thanks alot for that

[dasimpson1981]

no problem always glad to help

[dasimpson1981]

ok also wat current is used to hold the really open maybe the electro magnet needs more current then the transistor can supply

[steaming punk]

this might be the problem, it says 1A on it but i dont know if its min or max current for this relay to be functional

[randomness72.5]

(removed by author or community request)

[dasimpson1981]

yeah the box with the arrow is the variable resistor the arrow would be the middle connection on the variable resistor they are 3 terminals use on of the outer ones and the middle one

[hasow]

Hi people, I have tried to make the circuit but it doesn't work i'm not that good witch schematics, can someone help me please. i have linked all the parts like this:

[EngineeringShock]

The Schematic makes no sense. It is suggesting that there is always 9v tied to the base of the transistor. This will not only hurt the transistor, as there is no protective resistor, bit it renders the entire photo resistor divider circuit useless.

[lazarzoltan]

is no good

[hasow]

Can you help me do it good?

[lazarzoltan]

i dont can because dont found a good
sorry

[lazarzoltan]

hi peoples
I dont can make this
please anybody sand a good picture PPPPPLLLEEEEEEEEAAAAAAASSSSSSSSSSSSS

[randomness72.5]

I would like to know if anyone has actually got this thing working using Kipkays plans to turn on when the beam is broken and turn off after a few seconds.

[dasimpson1981]

skematics are great once you learn how to use them

they are when you know how to draw thewm properly

this skematic is wrong

[2muchfreetime8]

i have a question about the wiring of one of the components. the 5k variable resistor has three pins, that i understand. but wat is teh point of connecting two of the pins together, like in the schematic. this is something i have not understood for a while now.

[geekionizado]

I think this schematic is wrong, I made one, hope it cal help you http://img816.imageshack.us/img816/617/schematic.png

[achyutsaxena]

please send me another circuit diagram this one is confusing. send it on [e-mail] thank u

[Blue_Bird]

Can you replace the piezoelectric buzzer with a relay switch to activate another circuit? What modifications you would need to make the relay work. I only need the relay to work for a very short time to activate another alarm system.

[jules15]

you wouldn't have to adjust anything, just hook up the coil contacts where the siren is now.

[Goodhart]

If the signal going across that line activates a piezo, it will be ac....make sure your relay is not DC activated (as most are) or you'll get a lot of chatter from it.

[WinterIce8]

where can I find a variable resistor, I've looked at radioshack, frys, and the internet, but cant find one. but i found everything else

[dalucero]

a potentiometer is what you should look for to use as your variable resistor.

This appears to be the one he used:
parts.digikey.com/1/parts-kws/20-turn-potentiometer

Frys should definitely have these.

[kenverzets]

hasow that has done it this well done. work, i do but i do not understand the scheme .through

 

[jhunmar100]

understand the patter so you will done working! but if not really understand ask your friend or if you have a friend experts in electronic cybertronic ask him what to do and what the meaning of the circuit pattern so you will know how to make!! so very well thats only my help because im done of this instructable ^_^..
bye2x....

[celey19]

Hi, can someone please explain how the circuit is wired together.  Im not too good with schematics but im sure if someone could explain it more in depth (dumb it down a bit) i could do it.  Pictures would be great and helpful too but not necessary.  Thanks.

[cdousley]

skematics are great once you learn how to use them here are pictures should help you with more complicated parts remember all grounds to negative also try buying a breadboard if you don't have one they help alot also all the wires on that circle that say +9 volts go to positive end of the battery hope this helps.

[2muchfreetime8]

this circuit haunts me sometimes. i know that when the laser isn't shined at the photocell, it activates the circuit, and the resulting sound alternates loud adn quieter pretty quickly. i've looked at the circuit a dozen times, but i just cant figure out HOW it all works, how the componants influence everything. CAN ANYONE EXPLAIN THIS TO ME???!!!

[danilodene]

I'm from Brasil, I did the same project, but doesn't worked, kip sorry, but yours circuit is confusing, Can you explain or post a new diagram? thanks for everything

[XantorAmnobius]

One with a thyristor to make it stay on until turned off...

[mhkabir]

Did you make this with yenka??

[XantorAmnobius]

No - I used Crocodile Technology.

[mhkabir]

Yenka is developed by Crocodile Clips Inc. Crocodile technology is almost the same as Yenka

[thebestqrjls]

where can i get the thyristor please can you give me link please respond