Introduction: Extremely Simple Laser Alarm Circuit - a Tutorial Using Only Four Components!

Hi Everyone!

Edit: We now have a laser tripwire kickstarter campaign! Check it out here:

Laser Tripwire Kickstarter Campaign!

In the past, I've done several laser and light sensor tutorials that were op-amp (Operational amplifier) based. I've always been fond of op-amp based circuits as they are to easy to customize. This circuit is much simpler. All you need is an NPN transistor, a resistor, a light dependent resistor (LDR), and an active 5v buzzer. This video shows you how to build it, and how it works. The video offers a theory lesson, and a lab build. I used a 10k ohm resistor, a 2N2222 NPN transistor, a random LDR (Most will work well with this circuit), and a 5v active buzzer.

I also show you how to employ a 5v regulator at the end of the video. Just in case you want to use a 9v battery to power your circuit. I use a 78L05 5v regulator in the video, but you can just as easily use a 7805.

On another unrelated note, If any of you are Arduino fans, then I'd love for you to have a gander at my most recent Arduino Shield at kickstarter: ICU-Duino Arduino Kickstarter Campaign

I hope that you enjoy the video. Thanks again, everyone! Happy building!

Comments

author
paulsantony6 made it!(author)2015-10-20

excellent work

author
modern+man made it!(author)2014-12-14

Hey, great ible. Simple project, very well explained. I dabble in electronics & was looking for a simple, portable, laser tripwire circuit, et voila.

About This Instructable

3,859views

38favorites

License:

Bio: Hi there! My name is Patrick, and I am an electronics engineering technician who works full time as a lab tech, and part time as ... More »
More by EngineeringShock:The Viciously Simple Clap-ON Clap-OFF Circuit For ArduinoThe Multi-Program Laser Tripwire Set - Video User Manual!Creating A Resistor Based Keypad & Interface With Arduino!
Add instructable to: