Category Archives: mains power

Prepping For Power Outages

When the mains power goes, we are abruptly brought face-to-face with how many of the devices and services we take for granted rely upon it. Telephones for instance, where once they were attached to the wall by a cable, now they are a cordless device with a mains-powered base station. Your cellphone can fill that gap, but a modern smartphone with a battery life of under a day is hardly a reliable long-term solution. Meanwhile modern heating systems may still burn gas or fuel oil, but rely on an electric pump for circulation. Your kitchen is full of electrically-powered white …read more

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Mains Clocking A Microcontroller

[Lujji] is playing around with the STM8 microcontroller. In reviewing the official documentation for this chip, he read the external clock can be a sine wave, a triangle wave, or a square wave with a 50% duty cycle. The minimum CPU frequency is 0 Hz. [Lujji] doesn’t have a signal generator, and presumably, he’s all out of crystals. He does have mains AC, though, so why not clock a microcontroller with wall power?

Using mains power as a frequency standard is a concept a hundred years old. Synchronous motors turn at a rate proportional to the mains frequency, and this …read more

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Awesome Prank or Circuit-Breaker Tester?

Many tools can be used either for good or for evil — it just depends on the person flipping the switch. (And their current level of mischievousness.) We’re giving [Callan] the benefit of the doubt here and assuming that he built his remote-controlled Residual Current Device (RDC) tripper for the purpose of testing the safety of the wiring in his own home. On the other hand, he does mention using it to shut off all the power in his house during an “unrelated countdown at a party”. See? Good and evil.

An RCD (or GFCI in the States) is a …read more

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Posted in GFCI, home hacks, mains power, mains safety, prank, RCD, residual current device, test | Leave a comment