Fail of the Week: Solid State Relay Fails Spectacularly

A lot of times these days, it seems like we hackers are a little like kids in a candy store. With so many cool devices available for pennies at the click of a mouse, it’s temptingly easy to order first and ask questions about quality later. Most of the time that works out just fine, with the main risk of sourcing a dodgy component being a ruined afternoon of hacking when a part fails.

The stakes are much higher when you’re connecting your project to the house mains, though, as [Mattias Wandel] recently learned when the solid-state relay controlling his …read more

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Put The 3D Printer To Sleep So You Can Rest Easy

At this point you’ve probably already heard the news: cheap Chinese 3D printers sometimes catch fire. Now we can’t say we’re shocked to find out that absolute bottom of the barrel gear wasn’t designed to the highest standards (gotta cut those corners someplace), but that doesn’t change the fact that there are thousands of hackers and makers out there who are in possession of one of these suspect machines. Just tossing them to the curb is hardly the hacker way, so we’ve got to find ways to make the best of the hand dealt to us.

After sleeping with one …read more

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DIY SSR For Mains Switching

Typical power strips have their sockets tightly spaced. This makes it cumbersome to connect devices whose wall warts or power bricks are bulky — you end up losing an adjoining socket or two. And if the strip has a single power switch, you cannot turn off individual devices without unplugging them.

Planning to tackle both problems together, [Travis Hein] built himself some custom Dual SSR Controlled Socket Outlets for his workbench. He also decided to add remote switching ability so he could turn off individual sockets via a controller, Raspberry Pi, smartphone app or most ideally, a nice control panel …read more

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Dual-Purpose DIY Spot Welder Built with Safety in Mind

Ho-hum, another microwave oven transformer spot welder, right? Nope, not this one — [Kerry Wong]’s entry in the MOT spot welder arms race was built with safety in mind and has value-added features.

As [Kerry] points out, most MOT spot welder builds use a momentary switch of some sort to power the primary side of the transformer. Given that this means putting mains voltage dangerously close to your finger, [Kerry] chose to distance himself from the angry pixies and switch the primary with a triac. Not only that, he optically coupled the triac’s trigger to a small one-shot timer built …read more

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Light Dimmer Shows How to Steal Power from AC Line

We see a lot of traffic on the tips line with projects that cover old ground but do so in an instructive way, giving us insight into the basics of electronics. Sure, commercial versions of this IR-controlled light dimmer have been available for decades. But seeing how one works might just help you design your Next Big Thing.

Like many electronic controls, the previous version of this hack required a connection to a neutral in addition to the hot. This version of the circuit relies on passing a small current through the light bulb the dimmer controls to avoid that …read more

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An ESP8266 in Every Light Switch and Outlet

[Hristo Borisov] shows us his clever home automation project, a nicely packaged WiFi switchable wall socket. The ESP8266 has continuously proven itself to be a home automation panacea. Since the ESP8266 is practically a given at this point, the bragging rights have switched over to the skill with which the solution is implemented. By that metric, [Hristo]’s solution is pretty dang nice.

It’s all based around a simple board. An encapsulated power supply converts the 220V offered by the Bulgarian power authorities into two rails of 3.3V and 5V respectively. The 3.3V is used for an ESP8266 whose primary concern …read more

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