Connecting arduino to relay

When connecting an arudino to a relay, which pins of the relay connect to the arduino?

When connecting an arudino to a relay, which pins of the relay connect to the arduino?

The ones that make it go clickity-click. There is an input side to the relay - usually two pins - and an output side - usually 3 pins. Connect the input side to the Arduino - to ground and to a digital pin.

And, this is NOT a programming question.

aliali44:
When connecting an arudino to a relay, which pins of the relay connect to the arduino?

To turn the relay on and off using the Arduino you need to connect the relay coil pins. However, depending on the current and voltage required by the relay and whether the relay has a protection diode across the coil this may not be a good idea,

If you want the relay to control the Arduino then you need to connect the relay contact pins to the Arduino.

Which is it ?
Please provide details of the relay that you intend to use.

We want the arduino to control the relay coil (to energise it). The relay is a relay shield.

Thanks for all your help

aliali44:
The relay is a relay shield.

Best furnish details then. Have you looked at the manufacturer's website?

Best furnish details then.

Yeah, I’m having a really hard time understanding how you could be having difficulties installing a shield. They only fit one way.

I've noticed people often use the word "shield" when they mean a "breakout" or "module"

This is the relay board - but unsure which connections to plug the jumper wires to connect to arduino?

aliali44:
This is the relay board

Where? Looks like you forgot to link or attach :wink:

Usually relay board have two sides: one with gold pins (they will have some enumerated names like D0,D1...etc or In1..In2...... - those connect to digital pins in Arduino. Then you will have Vcc (sometimes two pins one for digital side one for Relay supply) and ground. Vcc connect to 5V (hopefully relay board logic is 5V).

Then there is the other side , usually with some screws, this is for the hi power load, like AC230V.

Like on this image. Note this blue jumper, this connects two supply voltages. If You want to supply your coils from different source (or voltage level, eg. in 3.3v microcontroller) you remove this jumper.

It may look different but general logic apply.