Solenoid Lock doesn't work

[donivi]

Hello all,

I am trying to make my Solenoid lock work as I expect. The code is simple - it should unlocks and locks again. The issue I face is that when I start my 12V power source the lock just unlocks and stays like this all the time and looks like the relay can't control it.

Here is my code:

#define RELAY_PIN 14

void setup() {
  // initialize digital pin  as an output.
  pinMode(RELAY_PIN, OUTPUT);
  digitalWrite(RELAY_PIN, LOW);
}

void loop() {
  digitalWrite(RELAY_PIN, HIGH); // unlock the door
  delay(5000);
  digitalWrite(RELAY_PIN, LOW);  // lock the door
  delay(5000);
}

Here is my wiring:

Can someone advice?

[madmark2150]

Disconnect the solenoid and see if the relay activates. Check NO-COM with an ohmmeter, you should see it make & break. If no, check input wiring, else recheck 12v power wiring. Does the solenoid kick when tested on 12V power directly?
Do you have a snubber/kickback diode across the coil of the solenoid? It's REQUIRED.
How is Arduino powered?

[paulpaulson]

Does the relay logic level fits to logic level of ESP32?

[awneil]

@madmark2150

Disconnect the solenoid and see if the relay activates

also if the relay deactivates when it should!

[awneil]

@donivi

void loop() {
  digitalWrite(RELAY_PIN, HIGH); // unlock the door
  delay(5000);
  digitalWrite(RELAY_PIN, LOW);  // lock the door
  delay(5000);
}

Put some serial prints in there to see it the loop is actually running - or getting "stuck" somewhere...

[arduinobotting]

Sounds like the issue is just what @ paulpaulson said. ESP32 has a 3.3v logic level and every relay I have seen has a 5v logic level, if that is the case you need to get a logic level shifter before doing anything with your script.

[donivi]

Hey guys, thank you all for your quick response. I already tried the lock and the relay separately - they work fine. The code also looks good. I am actually using ESP32Cam for the project. Let me upload some photos of the wiring:

The relayPin is on GPIO2. I am using a 5V power source from my laptop and 12V from a battery holder. The lock heats quickly also . It could be realted to the logic level like @paulpaulson said.

[awneil]

@donivi

I already tried the lock and the relay separately

Did you try the relay on its own, driven by the ESP ?

There's LEDs on the relay board - what do they show?

Please post links to the parts you are using - particularly the relay. As the others have said, are you sure it works on 3V?

@donivi

The lock heats quickly also

That would be expected when it is being permanently energised.

[awneil]

@donivi

I am using a 5V power source from my laptop

Looks like you're doing that via a "hacked" USB cable?

Are you sure that this gives enough power to operate the relay?

[donivi]

Hi @awneil, that hacked cable surely works because I recently powered some servos with it. The relay is blinking green and red which means it works I think. Here is a link to the relay module: Модул 1 реле 5v - it's a Bulgarian site.

[awneil]

I can't read Bulgarian, but that certainly seems to be saying that it's a 5V relay:

@donivi

The relay is blinking green and red which means it works I think

You really need to confirm that!
Doesn't the supplier provide documentation?

If the relay is working, you should be able to hear it clicking - can you?

If it is a 5V relay, it's possible that your 3V is just enough to operate the LEDs, but not enough to activate the relay...

[donivi]

Yes, when I put the 5V cable in I can hear the relay clicking.

@awneil

If it is a 5V relay, it's possible that your 3V is just enough to operate the LEDs, but not enough to activate the relay...

I think this might be the case ... So I need a level shifter after all, correct ?

[awneil]

This one looks very similar:

Jqc-3ff-s-z-05vdc 5v Low Level Trigger 1 Single Channel Road Way Relay Module...

On that one, the red LED is labelled "PWR" (short for "Power"?), and the green is "SW":

I would guess this means that the red LED should stay on with the power, and the green one should go on/off according to whether the relay is activated?

Again, you should be able to hear the relay clicking...

[donivi]

Thanks! I will try with another relay module ... I think this one is not suitable for this wiring.

[awneil]

It's not about the wiring - it's about the voltage levels.

[donivi]

I tried a different relay module and it worked! I am very happy to see that I can continue my project now! Thank you @awneil and all of you who answered on this topic.