Having some trouble getting a valve to properly actuate using a 12V relay. The LED indicator on the relay lights up when I send it a signal but the valve doesn't do anything. The valve will actuate when I hook up the leads but is unresponsive to the relay. I've tried switching the positive/ negative leadss.. Tried using normally open and normally closed on the relay and every other configuration I could think of. Any help is appreciated!

 

Hello,

Do you have the datails on the relays board?
Perhaps you have seen something over the head.

Bertus

 

Show us a complete schematic if possible. Particularly the connection to the Arduino.

When you say 12V relay, do you mean that the coil is activated at 12Vs? Or that the contacts are rated at 12V?

The Arduino outputs are at most 5V. This will/may be insufficient to activate the relay. You’d need a transistor or MOSFET to switch 12V to the coil.

If your unfamiliar with the Arduino, you may be confused by the fact that it’s power supply can be 12V. However, it has an onboard voltage regulator to bring that down to 5V. That’s the maximum it’s GPIO pins can supply. Further, they can only supply a max current of 20mA. Relays often draw more than that. Another reason why you need a transistor or MOSFET driver.

 

Can you tell us the model of the valve and show us your code please?

 

Hello,

It looks like that the relaysboard has optocouplers as inputs.
There must be an external powersupply connected for the relays.
As said, please post the datails of the ralays board.

Bertus

 

Thanks for the all the replies.

Here's some more pictures of my full setup: https://imgur.com/a/N2iqSoG

The LED indicator comes on which leads me to believe the Arduino is interfacing with it properly

 

This is the relay I'm using: https://www.amazon.com/Module-Optocoupler-Isolation-Support-Trigger/dp/B07K5D7XNW

 

I'm powering the relay with the 5V output on the Arduino. I'm also powering a bluetooth module with the same 5V pin. I'm not sure if this would cause any problems. The valve is being powered with a 12V battery pack. And it actuates when I hook it up to the batter as shown in the images.

 

Ahhh, I think I see what the problem is - or at least one. That is a 12V relay board. You need to have the connection to 12v DC+ and DC- and then the Arduino can operate them. They use optoisolators, but this board is not with 5v relays. See pic here https://www.amazon.com/dp/B07L7BDHW...d_r=0f843b75-322a-11e9-9bfd-ad0a97d0ca89&th=1 and here https://www.amazon.com/KNACRO-4-Cha...ocphy=9007808&hvtargid=pla-406153889171&psc=1

At least that it was it looks like to me.

 

Ahhh, I think I see what the problem is - or at least one. That is a 12V relay board. You need to have the connection to 12v DC+ and DC- and then the Arduino can operate them. They use optoisolators, but this board is not with 5v relays.

At least that it was it looks like to me.

I tried hooking up the relay to a 12V supply but now the LED input indicator won't turn on when I send it a signal
https://imgur.com/a/Th45kXo

 

Thanks for the all the replies.

Here's some more pictures of my full setup: https://imgur.com/a/N2iqSoG

The LED indicator comes on which leads me to believe the Arduino is interfacing with it properly

That is deceiving you. Look at the relays, they are clearly marked 12V. That is what they require to operate. You are not giving them 12V and they are not operating.

The link that you posted comes up with a similar board, but one with 5V relays. It has an option on the page to switch to your board, which has 12V relays.

I am sure that all three of us @bertus and @djsfantasi can see this and I have to admit that they both picked up on it while I was still looking.

 

I tried hooking up the relay to a 12V supply but now the LED input indicator won't turn on when I send it a signal
https://imgur.com/a/Th45kXo

Hang on and please go a little slower. There has to be documentation on the board. Off hand, I would say that the Arduino GND has to be connected to the battery gnd, but these are very common boards with lots of people using them and I don't have it in front of me.

 

You have the set the jumpers right

 

Hello,

The ground connection of the Arduino also must be connected to the DC- input of the relays board.
Without that connection, you will have a floating input.

Bertus

 

OK, as far as I can tell, this is how you have to hook it up. Be forewarned, I can't see a schematic.

In addition to how you have the battery hooked up in your first picture. Add a connection from +battery to DC+ on relay board. Add a connection from -battery to DC- on relay board. Add a connection from Arduino GND to DC- on relay board.

As @be80be noted, set the jumper switchs for how you want to Trigger the relays (Hi/Lo) from the Arduino code.

 

I would love to see a schematic. I can see the board has optoisolators but I wonder if they are being used - I have seen stranger...

edit to elaborate. If they had used optoisolators the way I would think they would be used, you would not have to tie Arduino GND to the external supply GND. Instead, there would be a terminal for Arduino GND and you would have the "proper" isolation - @bertus or anyone - am I seeing that correctly?

 

Hello,

The ground connection of the Arduino also must be connected to the DC- input of the relays board.
Without that connection, you will have a floating input.

Bertus

Perfect! This fixed the problem. Thanks for all of the help everyone!

 

Perfect! This fixed the problem. Thanks for all of the help everyone!

Are you saying that just connecting Arduino GND to DC- on the board made it so the relays now operate from the Arduino - that is, that the Arduino is operating those relays with 5V? That would be good information to know.

 

Are you saying that just connecting Arduino GND to DC- on the board made it so the relays now operate from the Arduino - that is, that the Arduino is operating those relays with 5V? That would be good information to know.

The relay is operating from the 12V battery. But yes I just added a wire between the Arduino GND and the DC- on the relay.

 

The relay is operating from the 12V battery. But yes I just added a wire between the Arduino GND and the DC- on the relay.

Ok thanks, that is what I thought.