Shift register not working with relays

Other Hardware General Electronics
1

So I'm working on a project and I want to connect multiple relays to a shift register. Everything in the shift register is working properly while testing with leds but when i connect the IN cable to the shift register OUT pins they are always HIGH even when the shift register is set to LOW.
I tried using transistors but I think i setted up them wrong because it was always flashing HIGH, LOW, etc.
Any way to fix this?

Parts being used:
Shift register: SN74HC595N
Relay:

Red cable: Positive
Black cable: Negative
Orange cable: Connected to OUT port of the shift register

Where I bought it: https://www.electrofun.pt/componentes-eletronicos/modulo-1-rele-sinal-12v-1-canal

I wont include code because it has much more then just the relays but I'm using the ShiftRegister74HC595.h library and the problem, I believe, is not in the shift registers since they are working fine with only leds.

The schematics of the connections between the shift register and the relay:

2

Hello and welcome.

Without more information, such as code, part numbers and a schematic and even a photo of what you have built no one can do much more than guess.

Please read
General guidance and
How to use this forum
How to post an image
The supply additional information so we know what you have, then maybe someone can help.

Thank you.

3

You can't directly drive a relay coil because it takes too much current. You need a driver circuit. Or you can buy a relay board with a built-in driver.

[u]Here is a MOSFET driver circuit[/u]. It's shown driving a 12V motor but it will work fine with a 5V relay. There are similar (but not identical) circuits using a regular bipolar NPN transistor.

Note that the "standard" 1-transistor or 1-MOSFET drivers are inverting. The relay coil is energized when the signal from the Arduino or shift register goes low. That's easily handled by inverting the logic in software.

4

PerryBebbington:
Hello and welcome.

Without more information, such as code, part numbers and a schematic and even a photo of what you have built no one can do much more than guess.

Please read
General guidance and
How to use this forum
How to post an image
The supply additional information so we know what you have, then maybe someone can help.

Thank you.

Added more info. Let me know if you need anything else!

5

A bit better but a schematic would really help, hand drawn is fine, not one minds if it's not neat and tidy but anything helps.

What relay modules are they? A link to where you bought them helps. I don't recognise them but maybe someone will.

Thanks.

6

PerryBebbington:
A bit better but a schematic would really help, hand drawn is fine, not one minds if it's not neat and tidy but anything helps.

What relay modules are they? A link to where you bought them helps. I don't recognise them but maybe someone will.

Thanks.

Added more info

7

Your link shows a 12V relay, your picture shows a 5V relay, which do you have?

8

5V relay

9

You say you "tried using transistors". Show us how you did that.

10

aarg:
You say you "tried using transistors". Show us how you did that.

This was causing the relay to keep going on and off even dought i setted it up to stay HIGH in the code setup

I-m not 100% sure this is what i did but it went something around that

11

Your module has a driver transistor on board. It should work perfectly well from a shift register. However, the relay side should never be powered from the Arduino 5V. VCC on the module should go to an independent source of 5V, not from the Arduino.

Also, as an aside, never go back and edit previous posts to update or add information that has been requested. It makes nonsense out of the replies and makes it hard for other people to follow.