Low voltage signal to trigger relay shield

I am working on a Project for myself and I am stumped as to how to go about the project.

I have a pressure transducer that i want the Arduino Uno to monitor the voltage, i than want to be able to set a value in the Arduino (1.6v) to than switch a relay in the relay shield that i have to turn off a solenoid.

i don't want the solenoid to turn back on until i press a button to activate the solenoid, than switch back off once the value (1.6v) is reached again.

i can find anywhere that some one has split the control circuit for the Arduino and the shield.

If anyone could shed some light on my project i will be very grateful.

Hello
Post your sketch and schematic to see how we can help.

The basic premise is that you have loop() always checking the analogRead() value…

When the input value moves across your on-off thresholds, it turns the output pin on or off as needed.

You can add millis() delays to implement any holdoff (hysteresis) you might want to add.

If your relay is only there to drive a DC solenoid, it’s possibly irrelevant, you can use your relay driver (MOSFET etc) to drive the solenoid directly!

Also, a tip that can be useful to save continuous power draw… use a PWM output to drive the relay/solenoid, because the coil requires more energy to pull-in than to hold - hence 100% duty-cycle for 100mS to pull the coil in, then back off to 30% duty as long as it needs to be held ‘on’.

my main concern for the circuit i would like to run is that the on and the off for the relay are two different signals.

ultimately i would like to have a pull to ground momentary signal and have the relay latch on and to have the relay unlatch when the value of the pressure transducer signal is above 1.6volts.

The Current draw on the solenoid is not much of a issue once its on as its still quite a low draw as its a solenoid that operates a valve pintal

Will attempt to draw a diagram this afternoon, it may only be slightly better than a finger painting but not alot better sorry in advance

My grandfather used to say:
"Ein Bild sagt mehr als tausend Worte" :wink:

I made a schematic but i cant upload the PDF as i am a new user , i must need a verfication

Not quite the English phrasing (">" instead of "=="), but the same import. :grin: