ATO Logic Help!
 

Hello All,

I'm building ATO for my reef tank, my idea is to apply 12v form Tunze Nano on Trigger board and it will activate relay and relay will turn on 24v solenoid.
Actual ATO is TUNZE Nano, so instead of pump I will be using solenoid.
(I have my RO water tank above my aquarium)
I got the power on the PCB got the power on relay circuit, but It's not working
I think I got a wrong device for my task, but maybe someone can help me.

Board has input for 5-24v DC and Logic pin (I guess for Arduino etc.), so the problem is it will not trigger relay without activating pin IN (see picture)
Is there anyway I can always put signal on IN (some how "short it" I guess)?
Relay module High/Low level trigger.

http://i842.photobucket.com/albums/z...pso7ewfcdh.jpg

Thank you!

You should be able to just move the 2 pin jumper to the L side (low trigger) vs the H side and then place a jumper wire across DC- and IN

Thank you for reply!

It works, but relay makes very loud buzzing noise.

I could be wrong, as I can't tell much about the inner workings of the relay from the photo, but there might not be a flyback diode installed inside it. Try installing a diode across the relay's outputs in a reverse biased position to see if that takes care of the problem. Motors and solenoids are prone to cause this problem, if a flyback diode is not included in the circuit.

So I installed 1N914 on the coil side, and it looks like it's working! It does buzz for half a sec, than stops, activates my RO supply solenoid.
So I tested by moving floater on TUNZE ATO, (simulating water level)
and on the 3rd time it start buzzing again. I checked diode, and it's OK
Specs on the diode is:
100v - 4A (max), I'm using it on 12v circuit, do you know why it possibly buzz again?

Maybe I need to add resistor in the diode chain? But maybe than I will need to know the specs of the coil correct?

Thank you.

Problem is solved!
I left the diode and added 1uF cap parallel to that diode, no more buzzing !!!
Thank you All FOR help!