How to Use a Relay With the Arduino

[SFS-V]

You not only make superhero gadgets but also arduino tutorials! this is one of the best channels!

[forstig]

it is so funny that the guy who I just watched for entertainment purposes now helps me with my technical project with an 11 year old video. and then it is even the one that gets it to the point the fastest thx

[MrBobWareham]

If you use this circuit then dont forget your blocking diode across the relay coil or you will have brown outs and reset plus you should use a transistor to switch the relay so all in all your video is crap 

[TiberiuCorbu]

This will burn your arduino pin eventually and even worse, the whole chip ... remember: a relay is a big consumer (uses ~150mA or more) which is almost 4 times more than what an Arduino pin can handle, along with this, a relay has inside a coil that can produce a current which will flow backwards. Read the articles bellow and remake this video.

Here is how you should properly connect a relay :

Here is a reference on arduino pins:

[JLaservideo]

I did a lot of projects like that in previous videos, I just moved on for awhile. Don't worry I'll make plenty more. :)

[Enigma]

Why you should not follow the advice from this video.

From the Arduino site:

Properties of Pins Configured as OUTPUT

Pins configured as OUTPUT with pinMode() are said to be in a low-impedance state. This means that they can provide a substantial amount of current to other circuits. Atmega pins can source (provide positive current) or sink (provide negative current) up to 40 mA (milliamps) of current to other devices/circuits. This is enough current to brightly light up an LED (don't forget the series resistor), or run many sensors, for example, but not enough current to run most relays, solenoids, or motors.

Short circuits on Arduino pins, or attempting to run high current devices from them, can damage or destroy the output transistors in the pin, or damage the entire Atmega chip. Often this will result in a "dead" pin in the microcontroller but the remaining chip will still function adequately. For this reason it is a good idea to connect OUTPUT pins to other devices with 470Ω or 1k resistors, unless maximum current draw from the pins is required for a particular application.

[FFSKevin]

Thanks guys. very informative. sometimes bad examples are good examples . 

[marks]

This is a TERRIBLE idea. Arduinos should never be hooked directly to a relay! A relay contains a coil of wire. Coils of wire can and do cause voltage spikes when the magnetic field collapses. It is extremely important to have a diode to protect the arduino from getting fried.

[phillipmichaels]

Please make more arguing vids because I am getting for my birthday and I am really exited

[choosetherightify]

Ummmm. What does this have to do with an Arduino? You are only using the power and ground output the Arduino to supply power to the breadboard. THIS VIDEO HAS NOTHING TO DO WITH THE ARDUINO. Thanks for the namedrop title that is completely misleading.

[musicfuse]

I thought the breadboard couldn't handle a lot of current like 110 AC power. I wouldn't like to try it with those skinny wires

[aleksd]

This circuit isn't safe, due to current that comes when you turn off your relay. You will also need a diode in the ciruit, in order to minimize the high voltage spike. This spike will kill your electronics in time. (Try it 40 times and you'll fry ur scheme)

[cavejohnson]

This isn't a joke. I have really old relays and those ones are cool because you can see them move. Don't say anything about this guy if you don't know it's true. He's probably smarter than you at this.

[gmorars]

Some relays comes whit a diode just or use a diode to protect

[jeffreyjbyron]

Hello, I know this video is old, but does this circuit work by default or do you need program the arduino to function like this? I need to build a toggle between 2 110v lamps (latching), and I want to control them with a momentary switch. I first thought about building a transistor based flip-flop connected to a relay, but I'm thinking arduino would be a lot easier. Please let me know if you can help. I have 2 days to finish the project...

[iScience]

did u just make a latch circuit or was that a push n hold switch?

[Mjerjawi]

Thanks for the video 
Can I use multiple relays like those with one Arduino without any resistors ?
There's no risk to damage the Arduino?

[RandyVollrath]

Do you need to have your finger down on the relay for it to work?

[SamuelginTV]

this is actually "how to use your arduino to power a relay". there's not much point in using a physical push-button switch to power a relay, which is an electrical switch.

[joshbolding]

Whats the part number on the relay? Or can you copy a link to your reply? The one in the description just takes me to amazon but not to a certain relay . thanks