12V Relay Electromagnetic door lock issue

Hi there,

I’ve been looking aroung for some answer but couldn’t find anything helpful.

The situation is :

I have 12V coming from my electric panel. The - is connected to the lock, and the + goes through an emergency button then goes to the lock.

I want to put an arduino between the emergency button and the lock.

I’ve tried several things, starting with transistor. With a BC139 (or 140 can’t remember) I succeeded in lowering the power going to the lock but not cutting it (why ? don’t know…)

Now, I’m trying to use a 12V relay (https://www.amazon.fr/gp/product/B01MZDH2ZT/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1). So :

  • Wire coming from - of electric panel to the COM relay
  • Wire comming from emergency button to NO relay

9V power supply to arduino Uno :

  • VIN of arduino to VCC relay
  • GND of arduino to GND relay
  • D9 of arduino to IN relay

My issue is : The diode on the relay blink with the HIGH, LOW I send, but no sound in the relay.
Interesting point : When I disconnet GND I hear the clipping sound, and if I connect GND back again.
(More) interesting point : The diode goes from really bright to lower but not off when the VIN is connected to VCC and goes on and off normaly if 5V from arduino is connected to VCC.

What am I missing ? Must be a trivial thing…

That link shows a pic of the relay but not the pin markings. What does that jumper do? My guess is that it's trying to energise the relay with the Arduino power which is probably not enough, and the relay coil needs its own power.

Can you post a pic of the relay from another angle to show the markings?

You also need 12V on the relay coils, not the 9v which you will be getting from the Arduino Vin pin.

I'm betting the pins we can't see are marked JD-VCC or RY-VCC?

edit... turns out there isn't a JD-VCC pin and jumper

If so, you should wire it like shown here, with that jumper off, and 12V to the JD-VCC connection (not 5V as in diagram, for a different relay). Then all the Arduino's doing is driving the LED in the opto via (Arduino) VCC to IN1/2. Don't connect the Arduin ground to the relay board, only the relay coil power + to JD-VCC and - to the relay board ground.

I'm not sure I get everything you said.

As you can see here : http://hpics.li/c36df5b there is VCC +IN- and GND pins on the relay.

You're telling me that I should try to put 12V on the relay and only the IN pin from the arduino ?

Kedae:
You're telling me that I should ...

Everything I said was based on the assumption that there was a JD-VCC pin, and a jumper on it. But that was wrong assumption and I have no idea what that jumper there is for, so can't advise on how it should be connected.

If there are maker's details on your board (the module, not Songle the relay maker) you should try find out more about the connections from them.

I want to put an arduino between the emergency button and the lock.

What are you trying to accomplish? Does the emergency button lock the door or open it?

Question:

Is the 12V from your electrical panel AC or DC? Here in the USA we don't normally have a low voltage output from our panels.

Here in the USA we don't normally have a low voltage output from our panels.

Perhaps you do. The doorbell.

What are you trying to accomplish? Does the emergency button lock the door or open it?

The emergency button open the door. In fact it's just a swtich cutting of the current to let the door open.

The emergency button open the door. In fact it's just a swtich cutting of the current to let the door open.

If it's an emergency exit button, what purpose does the arduino perform? Is the lock solenoid rated for 100% duty cycle?

Hi,

The emergency button open the door. In fact it's just a swtich cutting of the current to let the door open.

So if there is no power to the door lock, it is open?

Can you post a picture of your project, in particular the relay you are using?

Thanks.. Tom.. :slight_smile: