Category Archives: relay

Extech Power Supply: If it Ain’t Broke, Fix it Anyway

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[Wolf] came into possession of an Extech power supply that wasn’t quite in working order. It has been used in battery manufacturing and was fairly corroded. He was able to fix it but found there was an issue with the power supply that wasn’t a defect. By design when you turn off the outputs, the voltmeters read zero. That means you can’t adjust the voltage to a known value without turning on the outputs. Sure, you ought to disconnect things before you adjust, but you can only hope you’ll remember.

At first, he tried to use the existing output control …read more

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Sensing a Magnet with Local Sourcing

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I had a small project going on–never mind exactly what–and I needed to detect a magnet. Normally, that wouldn’t be a big problem. I have a huge hoard of components and gear to the point that it is a running joke among my friends that we can be talking about building something and I will have all the parts we need. However, lately a lot of my stuff is in… let’s say storage (again, never mind exactly why) and I didn’t have anything handy that would do the job.

Options

If I had time, there are plenty of options for …read more

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Ask Hackaday: How Do You Convert Negative Voltages to Positive?

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I have a good background working with high voltage, which for me means over 10,000 volts, but I have many gaps when it comes to the lower voltage realm in which RC control boards and H-bridges live. When working on my first real robot, a BB-8 droid, I stumbled when designing a board to convert varying polarities from an RC receiver board into positive voltages only for an Arduino.

Today’s question is, how do you convert a negative voltage into a positive one?

In the end I came up with something that works, but I’m sure there’s a more elegant …read more

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Bamboo Plant Becomes A Stylish Light Switch

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If flipping a regular old light switch or pressing buttons isn’t an adequately pleasing way to use your appliances around the house, how about poking at the leaves of a plant to turn on your lamp? [Xkitz] has provided a thorough breakdown of how to turn any conductive object in your living space into a nifty capacitive touch switch that adds a bit of charm to such an everyday action.

Creating an electrostatic field around a conductive medium, the capacitive touch relay constantly monitors this field and will toggle when any minuscule change to the capacitance is detected. …read more

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Kansas City Maker Faire: Pi-Plates

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As soon as he spied the Jolly Wrencher on my shirt, [Jerry Wasinger] beckoned me toward his booth at Kansas City Maker Faire. Honestly, though, I was already drawn in. [Jerry] had set up some interactive displays that demonstrate the virtues of his Pi-Plates—Raspberry Pi expansion boards that follow the HAT spec and are compatible with all flavors of Pi.

[Jerry] has developed three types of Pi-Plates to date. There’s a relay controller with seven slots, a data acquisition and controller combo board, and a motor controller that can handle two steppers or up to four DC motors. The main …read more

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Fail of the Week: Arachno∙fail∙ia

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Going down the list (FCC, CE, UL, etc.) we can’t think of a regulating body that will test for this failure mode. Reportedly, a $1M irrigation system was taken down by a spider. And an itsy-bitsy spider at that.

This fail turned up as a quick image post over on /r/mildlyinteresting but I wasn’t the only electronics person attracted like a moth to a flame. Our friend [Sprite_TM] popped in to answer a question about conformal coating. Seems this board was sealed in a waterproof enclosure but was obviously not conformally coated.

[Sprite_TM] also helped out with some armchair-engineering to …read more

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