Maker Pro
Maker Pro

Automated Water Mister (closed circuit soleniod switched off)

Richardegrant

Sep 25, 2017
3
Joined
Sep 25, 2017
Messages
3
Hi everyone this is my first time here, I know what I want to make but cant get my head around the reverse operational action I require.Yes my electronic knowledge is poor I'm more of a mechanical and engineering person. If someone could give me some guidance I would really be grateful.

I want to create a propagating misting system for the greenhouse but I want the soleniod to be turned of when the moisture sensor senses moisture. So when the plants leaf surface ( Moisture sensor) dries out the mister is switch on to cover the leaf with moisture. So I want the system to continuously keep the leaf surfaces moist. Please see my crude diagram attachedmister.jpg mister.jpg mister.jpg

Cheers

Richard
 

Minder

Apr 24, 2015
3,478
Joined
Apr 24, 2015
Messages
3,478
How is your electronic ability?
What is the nature of the signal out of the Moisture sensor?
A couple of ways, one is with a LM311 comparitor and a SSR to operate the solenoid if it is a AC solenoid.
More info on the sensor and solenoid would be useful.
M.
 

Alec_t

Jul 7, 2015
3,586
Joined
Jul 7, 2015
Messages
3,586
What is the voltage/current rating of the solenoid valve?

Edit: If using that particular soil sensor, this document says it needs a 3.3V-5V supply but it shouldn't be continuously powered.
 
Last edited:

Braeden Hamson

Feb 18, 2016
240
Joined
Feb 18, 2016
Messages
240
What is the voltage/current rating of the solenoid valve?

Edit: If using that particular soil sensor, this document says it needs a 3.3V-5V supply but it shouldn't be continuously powered.

Excellent catch, I imagine that's because of electrically accelerated corrosion?
 

AnalogKid

Jun 10, 2015
2,875
Joined
Jun 10, 2015
Messages
2,875
What is the manufacturer/part number/web page for the sensor?
What power is available for the monitor circuit?
What is the manufacturer/part number/web page for the solenoid?
Can you post datasheets for the sensor and solenoid?

ak
 

Richardegrant

Sep 25, 2017
3
Joined
Sep 25, 2017
Messages
3
Hi thanks for your replies, the soleniod uses 9v and is 0.6mA, sensor is going to be a simple piece of circuit board cut into like the pattern in my diagram to create 2 separate areas connected to by the 2 wires to be shorted ie closed circuit to trigger the switching off of the soleniod. Im thinking I need a NOT gate transistor circuit?
 

AnalogKid

Jun 10, 2015
2,875
Joined
Jun 10, 2015
Messages
2,875
sensor is going to be a simple piece of circuit board cut into like the pattern in my diagram to create 2 separate areas connected to by the 2 wires to be shorted ie closed circuit to trigger the switching off of the soleniod.
That is a *very* high impedance sensor. Also, it will continue to conduct until the water on it has evaporated. And, the salts and other goop left behind by many evaporation cycles will form a permanent conductive path.

ak
 
Top