Simple relay acting strange

I am using a Electronics-Salon DPDT signal relay module, 12Vdc RY12W-K to control a remote camera cable to fire a camera. I am powering it with 12v, and connecting it to a output pin on the Arduino to control it. On the other side of it connecting the camera cable to the NO contacts, and when they close it fires the camera, a simple two wire cable.

This all works fine except sometimes it does not fire or fires after a 1 or 2 second delay. There are times it fires immediately.

So connections are:

12v+ to coil
12v- to coil

Control to pin 12 on Arduino

“C” to one wire of camera cable
“NO” to other wire of camera cable

Am I doing something wrong?

Am I doing something wrong?

Yes. Even though you have posted 34 times on the forum, you have not yet read the forum guide in the sticky post. That will tell you the things that you are doing wrong that prevent us from helping you. Please be more respectful of the forum, if you truly want the forum to help you.

Here is the code

 digitalWrite(cameraFirePin, HIGH); //fires camera shutter through relay board
  lcd.setCursor(2,0 ); //moves cursor to position
  lcd.print("PHOTO TAKEN"); //alerts camera is shooting
  digitalWrite(cameraFirePin, LOW); //de-powers relay board

I am powering it with 12v, and connecting it to a output pin on the Arduino to control it.

How are you controlling 12V from an arduino output pin?

Would it not make more sense to just use a 5v relay as the arduino outputs 5v?

I'm new here so apologies if I'm missing something.


OP should have linked to the realy module.

And posted all of the code, not just a snippet that has nothing to do with the problem.

OP should have linked to the realy module.

And posted all of the code, not just a snippet that has nothing to do with the problem.

I see why that link is so important, it makes much more sense than a 12v Relay.


While this is in the forums guidelines it might help the OP if it was reiterated here.

To the OP,

You must realize folks reading this forum have no knowledge of what you have nor what you are trying to accomplish.

Looking at your post:

  1. you have 12 volts on a coil. I would assume you mean the coil in a car.

  2. you have the switch connected to the camera cable. Should we assume the cable is not connected to anything as you've not mentioned anything.

While the above might be a little "tongue in cheek" the idea is real. As you develop your electronic skills you will find often trying to communicate what your issue is and what you are trying to accomplish brings you to a solution before you even post. Simply trying to understand you issue enough to write it down will be very helpful for you.

In case the OP is still listening--allow me to give you [the OP] some details that are missing:

  • In case you haven't read the "How to use this forum" sticky, because you have no idea what that means--here's a link to it: How to use this forum
  • The "code" you offered, is not the complete code. Why do we need the complete code? Because, as much as you think everything you didn't show, is all hunky-dory, even the best of us has a "brain-fart" and get something wrong,--something that will jump out at another pair of eyes.
  • A schematic is a big help. It tells us what your intent is, and it gives us a way to notice things amiss.
  • A photo can also help. In fact, the more you can create a full picture, the better. In other words, the best of worlds would be us, there, in the room with you. But, since the Star Trek style Transporter hasn't been invented yet (as far as I know), the second best thing is photo(s) and diagram(s).
  • I can't read minds (other than my wife's mind, occasionally :wink: ), and it's very likely that no one else on this forum is capable of reading your mind. So, you need to be clear and comprehensive in your communication. As JohnRob suggested, try to write like you're the one reading it. Ask yourself, "Self, could you make any sense out of what you just wrote?!?" Remember, we aren't there. We have no history of you. We don't know you. We don't know how competent you are. We don't know what equipment or tools you have access to. There are NO REFERENCES for us to draw from. So, when you communicate, you need to take all of that into consideration.

Please understand…

Your predecessors in the electronics world have created a UNIVERSAL LANGUAGE called the “Schematic Diagram”. This is the language we (at least the ones who have taken the time to learn it) understand, regardless of our own native tongue.

A “descriptive text” explanation of a design has a lot of inherent issues. These include:

  1. Some parts are called different names in different languages
  2. Assumptions are often made about the reader’s expertise and ability to fill in the blanks. (Sadly, your fellow forum users often fail at being mind readers)
  3. Complexity of a circuit makes “LONG descriptive texts” a requirement and its just easier for all of us if you remember that even “A picture is worth a thousand words”

While anyone who is familiar with true schematic diagrams “cringes” when someone shares a Fritzing Breadboard Picture, its at least is more helpful than “Not having one”.

So. Your homework assignment, should you choose to accept it… is to figure out the answer to “What is all this Electronic Schematic Stuff anyway?”

I found the problem, it was the camera doing the delay. There are some settings on it for single shot, continuous shooting - low speed, and continuous shooting - high speed. It was set on single, so every time the electronic shutter release cable was closed by the relay it was waiting for the release of it.

So putting the camera in continuous shooting - low speed, it worked perfect.

Thanks for all the help.

I found the problem, it was the camera doing the delay...

Dang, that sort of thing crossed my mind--should have mentioned it--would have certainly looked the hero :grinning:

Cool---very glad you worked it out!