ive been searching for a way to isolate my arduino and all of its 5v sensors from my mains power.
without doing this it makes it hard to measure any kind of conductance of water that has other electronics in it that are plugged into the main ac lines.
for me to fully isolate the arduino i would need at least a 5v 3a power supply but i cant find anything.
i bought a "isolated" switching power supply on ebay but measuring the ac line to the dc outputs revealed that its not. what are my options besides using a battery
can i connect 5 of these parallel to get 5 wats output isolated?
Which Arduino, what sensors.So you have a groundloop problem.That's quite a lot of current, and that can't be passed through the Arduino. So what are you powering.Modern switching supplies could have a small capacitor between primary and secondary.It's possible that you measure some 'leakage'.Don't know how the modules will react.It is generally a bad idea to connect switching supplies in parallel.Leo..
Maybe isolate the signals.http://www.ti.com/lit/ds/symlink/iso122.pdf
i didnt ask if i could connect switching power supplies parallel i was talking about the dc dc converter in the link i posted
im not sure if isolating just the signal wire will do it. the ph senson im using has a series of opamps that do the conversion and send a 0 5v signal to the arduino through the analog port. im afraid since the ph sensors amplifier is powered by a non isolated psu then the ground on the ph probe will still loop?
These are 'signal amplifiers' where the input to output is physically isolated from each other.These isolated your transducer analog signals from a controller, PLC etc.These are similar to what an optoisolator does for digital signals.
How is Arduino powered? Have you tried powering it from a battery so it is isolated from mains? Post a detailed digram showing ALL components and how they are connected.
How are the pumps powered?