Arduino Relay

Hi Tony,

It looks like the 8 pins are all labelled. Usually you'd have 2 pins for power + and - (usually marked VCC and GND), and one pin per relay to hook up to a signal line.

The signal lines work just like the Blink example, but instead of the HIGH/LOW turning a light on and off it turns the relay on and off.

The only thing is that the relays could use a bit of power, so you probably need a separate 5v supply to connect to VCC/GND on the module. Plus you would connect GND of that supply to GND of the Arduino.

These boards are actually quite easy to use. I have one that has 2 relays (and 4 pins).

If you search for "arduino relay" on eBay you'll see similar modules with clearer pictures that show how the pins are marked.

Cheers,

-Nico

Thanks man, I think i understand. But I have another few question, to connect both the arduino and relay (using the signal lines you spoke of) will i need any special wires(Aside from standard jumper pins and power)? Or anything else that i might not have and need to order for the relay to work with the UNO? Also what are the limitations to this relay regarding how many relays can be on at one time, Volts, Amps, Watts, and any other limitations i should be warry of? And finaly are there any other relays out there that you would suggest more so than this one?

Thanks!

Thanks man, I think i understand. But I have another few question, to connect both the arduino and relay (using the signal lines you spoke of) will i need any special wires(Aside from standard jumper pins and power)? Or anything else that i might not have and need to order for the relay to work with the UNO? Also what are the limitations to this relay regarding how many relays can be on at one time, Volts, Amps, Watts, and any other limitations i should be warry of? And finaly are there any other relays out there that you would suggest more so than this one?

Thanks!

Hi Tony,

The easiest way to connect them is to use m-f jumper wires (search eBay for "breadboard jumper m-f" to see some nice ones).

In terms of relay limits, they normally have ratings listed on them which tells you how much you can switch with it. I found one on eBay that is similar to this Amazon unit you pointed out, and it says the relays are rated for 10 amps. So anything you run with that relay has to be less than 10 amps (that probably excludes heaters and coffee pots, but lights and fans should be ok).

In terms of how many relays can be on at once, that's the current draw rating of the relay. I think I saw that they draw 20mA each, so that's 120mA total to run all 6 at once.

The Arduino can handle 40mA per pin, though I'm not sure what the total max of all pins is, so it might be ok just running from the Arduino power. But if you add a separate 5v supply to power the module it should have plenty of power to run all 6 at once.

Also, you need to be careful of what you are running with the relays - if you run a single 10 amp wire to the box, you can only run a total of 10amps on the outputs. I recommend staying with low voltage and low power until you're familiar with how all that works.

Other options might be available if you search the e14 store, maybe Sparkfun or eBay too. I don't use them enough to have much knowledge of what is best

Cheers,

-Nico