Science and Data Acquisition LASER Security Systems – Level 2

Did Mr. Ochs check your work for part 1? Before you continue… Did Mr. Ochs check your work for part 1?

What You’ll Learn… Stuff You’ll Need… How to make a door chime that is activated when someone breaks or crosses a LASER beam How to setup a perimeter security system How to setup a grid security system Stuff You’ll Need… LASER and its power adaptor Security System and its power adaptor Photometer/Receiver (speaker) and power adaptor (3) front surface mirrors (2) audio patch cables

What You Should Know… It is very important that you know and follow all the LASER safety rules to prevent injury How to handle the LASER equipment carefully to prevent accidental damage to the equipment How to properly store the LASER communication equipment when you are finished for the day

Do It! Make a Door Chime Sometimes small retail stores are operated by just one or two people. When customers enter their store they need a pleasant sounding alarm to alert them that someone needs their assistance. Your security system in your LASER Communications kit can be setup to accomplish this task. Power Adaptor Power Adaptor Photometer/Receiver (speaker) LASER Security System Power Adaptor

Do It! Examine the Security System The Security System is packaged in an acrylic box like the LASER, but it is not a laser. It is the target or receiver of the laser beam, and it generates an alarm sound when the laser beam quits hitting its target. Reset Button Yellow LED Front View Back View AMP (speaker) Back View Target

Door Chime Setup Security System You may need to use a shim to adjust the height of your laser in order to align it with the Security System target Paper Shim

Do It! Test Your Door Chime When you get your door chime setup, your laser sends a modulated signal across the laser beam to the target of the security system box. That signal then loops back to the laser through the audio cable. If you break the laser beam your speaker should beep. When your laser beam is properly hitting the target a yellow LED should light up. The red reset button must be IN for this door chime, otherwise the alarm will not stop Press Reset Button IN Power Adaptor Speaker Receiver LASER Security System Audio Cable

Do It! Perimeter Security System Pretend that you want an alarm system to secure your backyard. Could you expand your door alarm system to accomplish this? Now you will need your mirrors. Mirror #2 Mirror #1 Speaker Receiver Mirror #3 Security System LASER Power Adaptor

Do It! Perimeter Security System You will find three front surface mirrors in your Laser Communications kit. What is a front surface mirror? Well, your bathroom mirror at home is a back surface mirror. The clear glass is in front with a reflective surface painted on the back of the glass. If you use back surface mirrors with your laser (which you can do) the glass will reflect and refract some of the beam, thus reducing the strength and concentration of the continuing beam. With front surface mirrors the laser beam does not have to pass through the glass, the beam hits the reflective surface immediately. The blue protective plastic needs to be removed if your kit has never been used. Adjustment Screw

Do It! Laws of Reflection and Refraction These diagrams will help you better understand why you need to use front surface mirrors to bounce your Laser around. You can also go online to learn more about the laws of physics and the terms involved. Try entering “ray optics” light refraction” and “light reflection” into your favorite search engine to find out more Laser beam is now split Angle of Incidence Angle of Incidence Angle of Reflection Laser Beam Ghost Laser Beam Angle of Reflection Reflective Surface Air Air Back Surface Mirror Front Surface Mirror Glass Glass Reflective Surface Angle of Refraction

Do It! Perimeter Security System This setup is much more challenging. Turn everything off except the laser. You will need to carefully set up each mirror, one at a time starting with mirror #1. Use the little adjustment screw on the base of the mirror to direct the beam where you want it to go. When you get the 3rd mirror to aim the beam at the security unit target, carefully turn the speaker and security unit on. It might take some effort and tweaking to get it right. Mirror #2 Mirror #1 Speaker Receiver Mirror #3 Security System LASER Power Adaptor

Press and Release Reset Button Do It! Perimeter Security System When all your mirrors are properly adjusted so that your alarm system beeps when you break the laser beam, carefully press and release the RESET button to arm the alarm. Once you have it armed try breaking the laser beam. What happens? It should now sound the alarm continuously until you press the RESET button again to turn it off. Mirror #2 Mirror #1 Press and Release Reset Button Reset Button Out Speaker Receiver Mirror #3 Security System LASER Power Adaptor

Do It! Grid Security System Pretend that you want to protect your candy from those who would try to sneak a piece when you are not looking. How would you do it? What entry points would you need to block? Would a perimeter security system adequately protect this pile of candy?

Do It! Grid Security System Think creatively about this problem. What are different ways you can use the mirrors to bend or move the laser around the room? Candy Mirror #1 Power Adaptor LASER Mirror #2 Mirror #3 Speaker Receiver Security System Power Adaptor