Category Archives: dc

Supersize DIY R/C Servos From Windscreen Wipers

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We’re all familiar with the experience of buying hobby servos. The market is awash with cheap clones which have inflated specs and poor performance. Even branded servos often fail to deliver, and sometimes you just can’t get the required torque or speed from the small form factor of the typical hobby servo.

Enter [James Bruton] and his DIY RC servo from a windscreen wiper motor. Windscreen wiper motors are cheap as chips, and a classic salvage. The motor shaft is connected to a potentiometer via a pulley and some string, providing the necessary closed-loop feedback. Instead of using the traditional …read more

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Everything You Didn’t Know You Were Missing About Bias Tees

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Do you need a bias tee? If you want to put a DC voltage on top of an RF signal, chances are that you do. But what exactly are bias tees, and how do they work?

If that’s your question, [W2AEW] has an answer for you with this informative video on the basics of bias tees. A bias tee allows a DC bias to be laid over an RF signal, and while that sounds like a simple job, theory and practice often deviate in the RF world. The simplest bias tee would have a capacitor in series with the RF …read more

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Hair Today, Gone Tomorrow, Via Electrolysis

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We think of electrolysis as a way to split things like water into oxygen and hydrogen using electricity, but it has a second meaning which is to remove hair using electricity. An electrologist inserts very thin needles into each hair follicle and uses a burst of electricity to permanently remove the hair. [Abbxrdy] didn’t want to buy a cheap unit because they don’t work well and didn’t want to spend on a professional setup, so designing and building ensued.

You’ll have to read through the comments to find some build details and the schematic. The device uses commercial electrolysis needles …read more

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Smart DC Tester Better than a Dummy Load

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Testing DC supplies can be done in many ways, from connecting an actual load like a motor, to using a dummy load in the manner of a big resistor. [Jasper Sikken] is opening up his smart tester for everyone. He is even putting it on Tindie! Normally a supply like a battery or a generator would be given multiple tests with different loads and periodic readings. Believe us, this can be tedious. [Jasper Sikken]’s simulated load takes away the tedium and guesswork by allowing the test parameters to be adjusted and recorded over a serial interface. Of course, this can …read more

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Open Source Motor Controller Makes Smooth Moves with Anti-Cogging

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Almost two years ago, a research team showed that it was possible to get fine motor control from cheap, brushless DC motors. Normally this is not feasible because the motors are built-in such a way that the torque applied is not uniform for every position of the motor, a phenomenon known as “cogging”. This is fine for something that doesn’t need low-speed control like a fan motor, but for robotics it’s a little more important. Since that team published their results, though, we are starting to see others implement their own low-speed brushless motor controllers.

The new method of implementing …read more

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In the face of government pressure, Kaspersky pledges to open new U.S. offices

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Moscow-based cybersecurity firm Kaspersky Lab announced plans Tuesday to open three new offices in the U.S. next year in order to expand business with American companies. The move comes as U.S. law enforcement and intelligence officials continue to discourage private businesses from relying on Kaspersky products to stop hackers due to reported security and privacy concerns. Chief executive Eugene Kaspersky confirmed the decision on social media after Reuters reported Tuesday morning that the anti-virus maker had plans to potentially close its Washington, D.C.-area office and instead open several other locations across the U.S. The D.C.-area office — in Arlington, Virginia — had been previously focused on serving U.S. government clients. In a Twitter post, Kaspersky said the company had already secured leases for offices in Los Angeles, Chicago and Toronto. Hi Chris, locations secured – Chicago, LA, Toronto — Eugene Kaspersky (@e_kaspersky) September 12, 2017 A statement provided to CyberScoop […]

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The Most Straightforward Wind Turbine

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We can all use a little more green energy in our lives at home. So when [ahmedebeed555] — a fan of wind power — ran into durability troubles with his previous home-built turbine, he revised it to be simpler than ever to build.

Outside of the DC generator motor, the rest of the turbine is made from recycled parts: a sponge mop sans sponge, a piece from an old CD drive case acting as a rudder, the blades from a scrapped fan, and a plastic bottle to protect the motor from the elements. Attach the fan to the …read more

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