OK - a 5V wall PSU, measure the output with an Analog in pin.
well... that's another way to MONITOR the grid voltage..... but it is not the point....
i'm talking about transforming SEVERAL 230v input into as much 5v inputs for the arduino...
i need a kind of "reverse" of the relay card shown above.
relay board :
arduino 5v input ---> RELAY ---> 230v output
What i need:
230v input ---> "what i need" --->5v output going to an arduino input
let me give you an exemple :
i want to Graft my arduino onto my standard electrical installation.
to lit a lamp, i use the wall rocker.
i can wire a relay in parallel of this rocker, or i can make a back-and-forth.
BUT, i CAN'T KNOW if the light is ON or OFF.... so i need to get the lamp wire ( going to the lamp from the rocker) powering an INPUT of my arduino.... ( through an "input board" )
you see what i mean ?
switching OFF a relay, to UN-power something that can be powered by somewhere else is not enough, I need to know the REAL status of my 230V outpout .
another exemple :
somme wall rocker switch have an integrated light bulb. this bulb is attacher to the OUTPOUT of the rocker, so show you the status of the lamp beneath the wall / door. it's obvious if you have only on rocker, in front of you. but if you have 2 rockers... each integrated bulb is connected to the same output, so when you switch ON any of the rocker, you get the status! i need the same, but going back to my arduino, as a solid 5V
so easy, but so hard to explain
