How to make a Laser alarm security circuit on breadboard (Step by step tutorial)

How to make a Laser alarm security circuit on breadboard (Step by step tutorial)


Let’s make laser alarm circuit using simple components. This clip shows how to make two type of alarm circuit. This is a 5V laser pointer module. Adjustable laser beam path by screw. 5V USB feeder cable Refer to the schematic. Connect CDS on the breadboard. Connect a 6.8kΩ resistor on the breadboard. Connect a buzzer on the breadboard. Check buzzer terminal polarity before connect on the breadboard. Connect a 2N7000(FET) on the breadboard. Refer to the leg layout. Connect a 100Ω resistor on the breadboard. Connect a LED on the breadboard. Check LED terminal polarity before connect on the breadboard. Connect 2N7000(FET)’s Gate and CDS according to the circuit diagram. Connect 2N7000(FET)’s Source and CDS according to the circuit diagram. Connect VCC(+5V) jumper wire on the breadboard. Connect GND jumper wire on the breadboard. Connect USB cable on the breadboard. Connect laser pointer feeder wire on the breadboard. Provide 5V electric power to the circuit. Adjust laser beam path aim to CDS. Buzzer is beeping when blocked the laser beam. Now let’s make continuous alarm circuit. FET is replaced in the circuit with SCR (BT169) Refer to the BT169 layout. Connect 16V 1μF electrolytic capacitors on the breadboard. Provide 5V electric power to the circuit. Adjust breadboard position to laser beam path. Disconnect power and reconnect. This is initial state. Once alarm activated, alarm is continuous beeping. Disconnect power and reconnect. Alarm is never turned off. This is very easy circuit. Everyone can make it.

100 Replies to “How to make a Laser alarm security circuit on breadboard (Step by step tutorial)”

  1. The video could have been great if you wud have explained while doing all connections. Pls can u do sumthing for it ??

  2. I did it, but the continuous circuit dosent work.i have tried 10uf,100uf,47uf,7uf capacitors but didn't use 1uf capacitor . Will it make a difference. If not what might be the reason for the continuous circuit to not work?

  3. Hey!
    Could someone please tell me, what exactly "CDS" is? It's for recieving the laser beam i guess. I tried to find it as an electronic component, but i didn't.
    Anyway, thanks for making this video!

    Cheers.

  4. can't help it. i hate videos without any explaining voice whatsoever. no thumbs up. ( no thumbs down also)

  5. The only problem of this is, its not mono-stable, that whenever the light is cut, the alarm should continue until the owner press a reset button with that, I designed it with 555 timer and works really good.

  6. Sir I did waterever u told but I am not getting the result .kindly give us a slow exp. video iam a school student I never teached about all this stuff.

  7. Nice! I have some questions:
    1) The laser is connected directly at 5 volts?
    2) What substitute this 2N7000 and BT169?
    Thank you

  8. Very Nice Project
    I used BT169 Transistor and 1uf Capacitor as you show but after every 14-18 min. buzzer start automatically, without any LDR interruption. can you tell me why this happen and what is the solution.

  9. Perfect, i will make one as well, was wonder where to get that beadboard but found many types of them on ebay, just need the rest
    http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.TRS0&_nkw=Breadboard&_sacat=0

  10. I think instead of 5v battery we can use 9v battery.Please reply because i want to submit it for my school project.

  11. Bro would u like to give me ur gmail id I have some problems I will explain u on what'sapp I will send my WhatsApp number on gmail

  12. Hoping you can help. I'm trying to make something that produces the same result (buzzing) except want to do with with just one laser pointer type device without the receiver end (the part you have on the bread board).

    For example, I want to be able to shine a laser pointer as a rather large wall clock I own, and when the second hand passes, and breaks, the laser pointer light beam a buzz will occurs. I won't have access to the inside of this clock. Thoughts on what I should google to accomplish this?

  13. What is the value of the capacitor and where you have attached it i did not understand please anyone reply fast

  14. Hi Thomas Kim, could you pls upload the circuit diagram or could you email it to me [email protected] we are doing a science project and we are not getting an output, please help us with the circuit , we have all the necessary components as per the videp

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