{"id":55,"date":"2013-07-14T20:13:00","date_gmt":"2013-07-14T20:13:00","guid":{"rendered":"https:\/\/blafaselblub.wordpress.com\/2013\/07\/14\/frankensockets"},"modified":"2018-01-09T14:01:05","modified_gmt":"2018-01-09T13:01:05","slug":"frankensockets","status":"publish","type":"post","link":"https:\/\/blog.alexander-tuxen.de\/index.php\/2013\/07\/14\/frankensockets\/","title":{"rendered":"Frankensockets"},"content":{"rendered":"

I hate tinkering with AC mains. But if you want to get “real” things done around the house there is no way around it. So before this goes any further, here is the disclaimer:<\/p>\n

AC mains power is dangerous. It can kill you and\/or burn your house down if you are not careful. Unless you know exactly what you are doing, DON’T TRY THIS AT HOME!<\/b>
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\n<\/b>That being said, AC mains is no rocket surgery either and probably no one in their right mind would call a union electrician to hook up a lamp.<\/p>\n

So, what is there to switching mains? Not much, actually, it’s just a sufficiently rated relay to switch the hot or neutral wire (it doesn’t matter which, either will break the circuit and prevent current from flowing).<\/p>\n

There is a variety of readily made hardware available that will accomplish this but from my point of view all these products are flawed: The ones that work reliably are expensive and the cheap ones are unreliable.<\/p>\n

Hardware:<\/b><\/p>\n

I had a few very cheap and extremely unreliable ones around, so the obvious solution was to gut them and use the enclosures for my own design.<\/p>\n\n\n\n\n
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I got these about 20 years back, as you can tell by the grime.. The set of four was about 30 DM, back in the day.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n\n\n\n\n
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All those certifications… Must be good stuff inside…<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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The enclosure looks quite nicely engineered. But what is it with that crappy and kind of burned looking circuit board?<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

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Yuck! This isn’t even a cap dropper, this is basically just a resistor on a mains wire, and it looks fried up pretty good. How did they get all those safety stickers with this?<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
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The design itself is simple: Just hook up a relay to an Atmega with an RFM12B. If there wasn’t the issue of a power supply. Looking at commercially available solutions there seem to be mainly two options: Go with a full blown switch mode power supply or implement some sort of ultra cheap non isolated cap dropper<\/a> type power supply. Both have a list of pros and cons:<\/p>\n

SMPS pros:<\/p>\n