Yes, newbie here. From what I've learned thus far, I can raise the voltage from the Arduino to make a solenoid or relay os SPST switch turn on to allow lots of current through.
I would like, instead, to have the low voltage at the Arduino side go high when someone turns on the large AC voltage. Seems like a reversed relay :).
I realize this is something obvious but I've been Google searching anything I can think of, and it always points me to the normal small voltage enables large voltage device and I would like the opposite.
What am I looking for :)? Even what to search for would help. I only need to know the on/off state of a 120VAC pump. Seems like an easy project ;).
Simple way - wire a 5V wallwart in parallel with the pump's 120V motor. When the pump is turned on, the wallwart will output 5V, you can monitor that directly with a digital input. Use 1K load resistor on the wallwart input so any output filter caps are discharged when the power is removed from the wallwart input.
Sorry. I forgot to mention that it is a sewage pump and all I have access to is the end of the plug :(. So I can not get in to the motor to attach anything to activate with the motor :(.
I was hoping for something to plug my plug in to that would register when it is powered up?
CrossRoads:
Simple way - wire a 5V wallwart in parallel with the pump's 120V motor. When the pump is turned on, the wallwart will output 5V, you can monitor that directly with a digital input. Use 1K load resistor on the wallwart input so any output filter caps are discharged when the power is removed from the wallwart input.
That's a pretty neat solution, I was thinking about a simple voltage divider, but then you have to throw some diodes at it (AC) and perhaps a filter cap. The wall plug solution is brilliant. Easy execution with one of those multi outlet extension cords.
Just call me paranoid. Seems everything I spec close to the right power ends up melting :(. Plus, if it works for a pump, I'm hoping to test it for other things ;).
