From: gordon+usenet@drogon.net   
      
   In article ,   
   Mike Scott   wrote:   
   >Hi all. Two separate projects which will need a relay of some sort to   
   >run from a Pi or similar.   
   >   
   >I'm really looking for something plug-and-go rather than build-your-own   
   >(especially item 2 below)   
   >   
   >First is a dpdt relay to switch around 12-20 V at a couple of amps. spdt   
   >are easy to come by; the only dpdt ones I've found are on aliexpress,   
   >but their longevity is possibly open to question :-{   
   >   
   >Second is something to switch mains safely - a full 13A to run a 3kW   
   >heater. I've drawn a blank: best I can think of is to butcher one of   
   >those wireless mains switch modules, which would at least provide a good   
   >isolation gap :-)   
      
   I used a solid state relay to control an oven some years back - the   
   Pi's 3.3v output was good enough to fire the relay although it's LED   
   was rather dim.   
      
   The oven was only 2.2Kw though, but I used a relay rated for something   
   like 40 amps (that's probably chinese amps, but it never failed in the   
   5 or so years I used it near daily when I was running my small bakery)   
      
   For a 3Kw project (Atmega, not a Pi) I used one of the SparkFun "Beefcake"   
   relays.   
   I think it did need a 5v signal though. You'll need a driver transitor from a   
   Pi.   
      
   https://www.sparkfun.com/products/13815   
      
   I built that into a control system in a micro-brewery 'washing machine'   
   about 5 or 6 years back and its still running today.   
      
   Gordon   
      
   --- SoupGate-Win32 v1.05   
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