Laser Security System. Here is a simple and cheap Laser Based Security System, which costs below Rs. 100.
It is a simple circuit using LM358 OP-AMP and LM555 Timer. This circuit is triggered when the Laser beam falls on the LDR interrupts, which sounds the buzzer connected to it. This can be used to protect your valuable items, money, room etc.. By using different mirror arrangements you can form different security systems. This can also be used to protect more than one objects by suitably arranging mirrors. Mirror Laser LDR Arrangement In this arrangement Mirrors B,C,D are arranged such that the reflected beam is making 90° to incident beam and the Mirror A is placed such that the beam form Laser falls on the Mirror B and the beam from Mirror D falls on the LDR. Circuit Diagram Laser Security System Circuit Diagram Working In this circuit the IC LM358 ic is working as a comparator and IC LM555 is wired as a bistable multivibrator. AT89C51 8051 Microcontroller Based Projects. Coder for Raspberry Pi.
A simple way to make web stuff on Raspberry Pi.
Mac users, just run the provided installer.PC users, check out our Windows-specific Instructions for more installation details. Raspberry Pi Tutorials. Fake TV - Burglar Deterrent. I was shopping around on Amazon the other day and came across a product that I thought was genius.
It is called Fake TV and it acts as a burglar deterrent while you are away from the house. At night, the Fake TV turns on and uses a series of LEDs to project random colors that looks as though someone is inside watching TV when viewed through curtains or shades. There are some videos of it in action on YouTube and I have to say it really does look like someone is inside watching TV. This should scare off the large majority of petty thieves that are just looking for the quick opportunity.
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Repel Mosquitos, Dogs, & Annoying Friends with High-Frequency Tones on Android « Android Gadget Hacks. Repel Mosquitos, Dogs, & Annoying Friends with High-Frequency Tones on Android There are few sounds that actually make me cringe whenever I hear them: silverware scraping on a plate, nails scratching on a chalkboard, and piercing high-frequency tones.
While the former two terrors require some physical hardware, sending out high-frequency sounds is as easy as downloading an app. Of course, since high-frequency sounds are terrible things to hear, this app is great for classroom and office pranks, or quite possibly fending off dogs and bugs. Try this at your own peril (I suggest using earbuds or earplugs). Step 2: Deploy Your Attack on Surrounding Eardrums Sounds are separated into two sections: Start and Repeller. Under the Start section, you'll find your basic frequencies ranging from "Light" to "Very Heavy," followed by locked options for the Platinum version. Under the Repeller section, you'll see just two options: "Mosquito repeller" and "Dog repeller. " HowStuffWorks - Learn How Everything Works! Types of Skills Everyone Should Know – Video – Top 100 Important Skills.
Split Firewood Seasoned splitters use a maul, not an ax, to prep firewood. (With its slim taper, an ax head often gets stuck in the end grain.) Don't use a chopping block—it reduces the arc of the swing, which decreases power. Instead, place the log on the ground, 5 in. closer than the length of the maul handle. Michael Lewis. How to do anything. DIY projects, how-tos, and inspiration from geeks, makers, and hackers. Main Page. How to Splice Christmas Tree Lights. Fresh hacks every day. National Institute of Electronics & Information Technology. Homemade Circuit Designs Just for You.