Inside a Roomba The Roomba Red is approximately 13 inches (33 cm) in diameter and 3.5 inches (9 cm) tall. An external examination reveals the following parts: Roombas run on a rechargeable NiMH battery. The Roomba Red battery pack is rated at 3 amp-hours and takes about seven hours to fully charge to about 18 […]
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What exactly is a transistor, anyway? Transistors are devices that control the movement of electrons, and consequently, electricity. They work something like a water faucet — not only do they start and stop the flow of a current, but they also control the amount of the current. With electricity, transistors can both switch or amplify
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How it Works: The Science Behind the Magic Way back in the early 1920s, when Léon Theremin worked at the Physico-Technical Institute in St. Petersburg, Russia, he noticed that when he moved his body in or out of an electromagnetic field produced by a radio frequency oscillating circuit, he changed its frequency [source: Harrison]. The
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Get Your Bits Fit FitBit is evolving, from both a hardware and software perspective. In October 2011, the clip itself was upgraded and renamed the FitBit Ultra. The Ultra has the same features as the original FitBit, with one major addition: an altimeter. With the altimeter, Ultra knows how much elevation you lose or gain
Basic Idea Behind Fax Machines Most of the early fax machine designs involved a rotating drum. To send a fax, you would attach the piece of paper to the drum, with the print facing outward. The rest of the machine worked something like this: There was a small photo sensor with a lens and a
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Building Up to NFC Back in 2004, three big companies — Nokia, Sony and Philips — got together with the goal of establishing a standard for near field communication technology. While these companies worked to standardize NFC, the technology that makes it possible dates back much further. And it all begins with the relationship between
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Electrostatic and Dynamic Transducers To hear what’s recorded on a record, cassette, CD, DVD or MP3 player, data stored on the medium must be converted into sound waves. This requires that the stored information be turned into an electrical signal, which then must pass through a transducer to convert the transverse electrical wave into a
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The Mechanics of the Air Multiplier There are blades in the fan — you just can’t see them. The pedestal hides the blades. A motor rotates nine asymmetrically aligned blades to pull airinto the device. According to Dyson, these blades can pull in up to 5.28 gallons (about 20 liters) of air per second. The
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This project is a broadband field strength sensing probe that has a 15cm antenna. It is able to detect radio energy and read the output on a common multimeter millivolts scale. It can be used to test 4MHz, 35 MHz, 55 MHz, 100 MHz, 384 MHz, 900 MHz, cell phone, and microwave oven. The meter is
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What is Stun Gun An electroshock weapon is an incapacitant weapon used for incapacitating a person by administering electric shock aimed at disrupting superficial muscle functions. One type is a conductive energy device (CED) fires projectiles that administer the shock through a thin, flexible wire. Other electroshock weapons such as stun guns, stun batons, and electroshock belts administer an electric shock by direct contact.
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