Running a 5v Relay module from an Arduino

Super Quick Question. I want to run a 5v relay and I'd like to run it from the Arduino (Digital Pin 6 for the sense and 5v pin to power it).

That's the type of relay I have.

So I don't know if I need to use a transistor to help drive it or.....

I'm planning on using a 2n2222 if I have to.

So I don't know if I need to use a transistor to help drive it or.....

You can't tell from the poor information given in that web site. Have you got this in your hand? If so look at the PCB and see if there is a transistor on the board. It will be surface mount and have three connectors. If their is then their is no need to use one.

Went to another site which shows a better view and it does have an SMD transistor for driving the coil along with a kickback diode.
http://www.dx.com/p/arduino-5v-relay-module-blue-black-121354

OK so It would be perfectly fine to run the relay off of the arduino?

IIRC, this module has very little creepage distance between the Arduino side and the relay contacts.
This Keyes module is ok for low voltage, but could be dangerous for mains voltage switching.
Leo..

I'm planning on using it to run a 12 volt motor so i think it would still be fine right?

Ok for that.
How are you powering the Arduino, and which Arduino.
Are you using a back-EMF diode across the motor terminals.
Leo..

I'm using a car antenna that has a sense wire. The antenna will have a separate power supply from the Arduino. So the relay will trigger that 12v sense wire. I think I might still need a diode for the sense wire. I'm using an Arduino Uno.

Don't know what's inside a motorised car aerial, but if it has three wires (a pair for power/ground), then the control wire shouldn't carry that much current. just try without diode.
Leo..

Cool! So I can use the 5v relay and I'll be fine?

Probably. Assuming there are no other Gremlins.
Leo..

Okie cool, thanks! I'll watch out for those Gremlins!

Here is a complete write up of said relay module and connections to Arduino

Keyes SR1 Y Relay Module

MarkDerbyshire:
Here is an almost complete write up

It's silent on the matter of the relay coil current, which the datasheet tells us is a little over 70mA. (The "L" in the "SL" of the relay part number tells us it's 0.36W version.)

It's important to know the current in case you need to run a bunch, and / or have other stuff on the Arduino 5V pin.

HeafBeide:
It's important to know the current in case you need to run a bunch, and / or have other stuff on the Arduino 5V pin.

Well that particular circuit only has One yes "One" Relay involved so your point is pretty irrelevant. The OP is only running "one" - read it again - "one" (or "1" just in you pick that up) relay so again your point is irrelevant in this case

That link's not a complete write up of using that the relay, whatever one's immediate needs are: knowing the current's always important.

And, MD, don't be that guy who thinks it's not important to learn at least a weeeee bit more than needed just for the particular instance.

And also never forget that, on a forum, anyone can wander along and read, and that's one good way for knowledge to spread.

You have a PM to tell you what I really think.

Hi,
Songle Relay Specs.

Tom.. :slight_smile:

SongleRelays.pdf (96.4 KB)