high voltageoutlet
I want to use an Arduino to control my 220V outlet.
I have searched the web and stack a couple of hours and all I found was this product from Sparkfun and Adafruit, but it does only take 110V and it is an American outlet.
Neither the Weemo will work here in Denmark.
Our outlets in Europe (Denmark) look like this.
I want to avoid to work with high voltage (and possible a fire). How?
One thing that the other answers did not cover, the line coming in to your house is actually 3 lines from a transformer with a center tap. That center tap is the "cold" and the two ends are both "hot", to get 120 you go from the center to one of the ends and to get 240 you go from end to end
In your breaker box it alternates which end is available each line, that is why 240 breakers are two wide, it is connecting the two ends together instead of the middle and the end.
Similar principles apply with the following major differences
That sounds like your Arduino is getting corrupted from noise spikes on switching the AC load on and off. The reason a glue gun affects it less, is that as a pure resistive load, it doesn't generate very much noise, but the alarm clock probably has a switching power supply in it that is dumping higher frequency noise back on the line. Even an older motor driven clock can put spikes back on the line depending on the motor and how it is controlled. Have you tried using an AC filter between the relay(s) and the load (Not a surge suppressor, but an actual LC filter)?
It is also possible, though from the description, unlikely that the relay coils themselves are generating enough of a spike to corrupt your processor. Industrially, for just that reason, we use RC snubber networks across the coils of just about every relay/solenoid driven by an electronic output.
Also the above advice is 100% correct, do NOT switch the neutral of your AC load. Very bad business there from a safety (and at least US Code) standpoint. If the neutral must be switched, to be code compliant, you would need to use special safety relays with force-guided contacts in series.
Best Answer
I share Andys idea of modifying an existing remote controlled socket.
Nexa has a couple of remote sockets that works well in Sweden. Probably works in Denmark too... :)
http://www.pricerunner.dk/sp/nexa.html
The outdoor version works really well with heavy loads and at low temperatures. They are available in a pack with a remote.