Here's a great, simple Make project that teaches you how to make an intercom from a pair of old, corded phones, a 9V battery and a resistor. I loved walkie-talkies and intercoms when I was a kid -- the idea of setting up your own house-wide wireline intercom is super-cool, and the project is dead-simple.
At its most basic level, a telephone network is just two microphones, two speakers and a power source. In this project we are reducing the phone to these basic elements. The handset of the phone contains the speaker, the microphone and any necessary processing circuitry. All we need to add is the power source.
A regular corded telephone doesn't require much electricity to operate. It just needs about 9 volts and less than 30mA. It normally gets this from the phone line itself. This is why many phones can still work even during a blackout. However in this project, we are using a single 9 volt battery to power our phones.
The battery is wired in series with a 300 ohm resistor and connected to either the red wire or the green wire in a phone cord. The phone cord is then plugged into both phones. The battery is able to supply enough electricity to power the speaker and microphone circuits of both phones. This allows you to use them to talk back and forth.
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The LG Watch Urbane 2nd Edition LTE was the company’s latest answer to Apple’s dominating entry into the market. But it died fast, pulled off the shelves within a week due to an unspecified problem with the display. Ron Amadeo writes that they “are not in a position to communicate the specifics of the issue […]
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These knitted gloves are here to save the day (and your hands) with an ultra-comfy, double-layer that will allow you to stay warm and use your phone. Now you can take photos on the fly, text, Tinder, and more without letting freezing temperatures get in your way. Plus they work with all touchscreens, so no […]