You will need an adaptor to split the 12V so it can connect to the Buck and solenoid.
Yeah that barrel jack is what I have
Alrighty then, thanks!! Sorry for the many questions, I am just being cautious since I am a bit new to hardware.
No problem.
The solenoid in post#18 needs a kickback diode across the solenoid.
Not doing so will quickly weld the relay contacts shut.
I would use a mosfet module instead of a relay.
You still need that diode across the solenoid.
Leo..
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Was considering this as well. But is an IRF520 just as decent as this one?
No, it will lead you to the same problem than with that low-trigger relay: not compatible with 3.3V trigger.
So either you pick relay or mosfet module, make sure it's good for 3.3V.
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If you mean one of these, they don't even work with a 5V Arduino.
Do not buy one for any Arduino project.
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I see the relay, the buck, the solenoid and the ESP32 board but what are those other two things at the top?
I see the relay, the buck, the solenoid and the ESP32 board but what are those other two things at the top?
RC522 Readers for RFID
Well the 12V, relay, buck, solenoid connections look correct but I don't know anything about your RFID connections.
It might be good idea to test your setup in steps. When your solenoid setup works without hiccups, go forward. Debugging the whole setup at once can be challenging...
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With 12V available, why not use a relay with 12V coil (30mA) instead of 5V (75mA)?
Would be nice if the makers of these cheapo modules would spend an extra 3 cents and put in a separate common input terminal to completely isolate input from output / coil supply terminals.
Many of them do, the one I posted #29 has separate coil supply and you can find also 12V version. I just can't confirm that the trigger at 3.3V is sufficient for the optocoupler which has series resistor X designed for 12V. Probably yes.
If you’re talking about one like this, the GND terminal on the “JD-VCC” block and the GND on the input block are connected together so NOT completely isolated.
Most of those relays don't need a ground connection to the Arduino,
because the opto LED is connected between VCC and IN.
You do of course need a separate supply for the relay coils if you want/need opto isolation,
otherwise you still have a common connection via supply ground.
Leo..
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Correct!