Control High Voltage Devices - Arduino Relay Tutorial

[@lionking2424]

I am an Electrical Engineer and I say thank you for this video. You did a great job by warning people from the beginning of the video. I do not understand why some people are saying you do not what you are doing. You sound like a very educated person. You explained VCC and JDVcc very well. I did not know Vcc and JDVcc until my second year of college. It is a very deep topics in electronics. You used it a lot when learning about transistors. You are sharing your knowledge for free through the Internet. We all should be grateful and say thank you. Keep on the good work!

[@RatomirFilipovic]

Maybe coz he used blue wire for phase and green/yellow for ground... i admit green/yellow can be used as ground but only when there is no 0 in system... Blue=0, brow,black,grey= phase... Yellow/green= ground... and it is important to fallow this rules since hes doing 220v. There is also color matching for 24v,12v,5v and 3v and many other signals.... He did explain it kinda good but he made mistake no electrician should ever make...Thats how ppl die.

[@matteofalduto766]

DANGER: NEVER USE THE YELLOW-GREEN CABLE AS THE LINE (HOT) WIRE!!! The yellow-green cable must be used for ground only. This is extremely important to avoid accidents. (Someone can get hurt if not by directly touching it, by touching, for example, the casing of a device that has been mistakenly “grounded” to the line). Also, you should always connect the ground terminals when they are present, as in this case, on both ends of the power extender. People using it might rightfully assume they are connected, when in fact they are not. Sorry for being so harsh, but this really needs to be pointed out to anyone blindly following this tutorial.

[@danieltuba3843]

When a 5V guy works with 230V system. *painful facepalm*

[@lekashameti6865]

oh waw!

[@hugocarrasco7734]

So does this mean “never cut the positive/yellowgreen wire”? So you should only break the negative wire? I’ve only heard this once. Can u explain again in further detail?

[@guymontag2948]

That's my second Arduino project and the intimidation factor is steadily decreasing. Thank you from 7 years in the future.

[@kean3545]

As I just started with Arduino, it is nice that people like you helping us out. I have 1 point that need some attention (I know you take no responsibility of any of our actions). In the powercable you cut the ground wire (yellow,green) to build in the relay. If someone uses a prefab power line and does it the same way.... the RCD will be activated. So please be aware of the color code of the wires (Europe is different than North America)

[@nazranzafran3807]

Europe use what

[@carlosbermudez4444]

Finally, a video that illustrated to me the purpose of JD-VCC and VCC with the illustration at 4min mark. I say thank you for this video.

[@lapidations]

I'd like to add that, if you did this and your Arduino resets sometimes when switching off your load, I'd bet that your load is inductive (motor, big relay, solenoid valve, any other electromagnetic device). You need to add a RC Snubber between the relay contacts (not the relay coil), in other words, in parallel with your load. It took me a lot of time to find this out so I hope this helps others. A 0.1uF capacitor in series with a 100ohms resistor rated for at least 1W should be enough.

[@screeningstudio3868]

Hi, thanks for that information and i have 1 question, lately i have been trying to connect my plasma with my arduino uno using 30A high volate isolated module relay, when i sending the command my arduino sometimes act like crazy, like resetting all the grbl settings, and delay too long to complete a g code command and also make my homing suddenly unavailable , is that because the plasma cutter is using high frequency to start the arc or because of the relay? The plasma machine is running 40A, but the relay is running at 30A maximum? Is the load is too much or it is because of the high frequency that make the arduino going crazy

[@HighVoltageMadness]

You should never ever wire mains wiring like that. Don't ever use the earth wire for the hot, use the black or brown for hot. The earth wire is never meant to carry voltage. Don't be lazy, strip and connect the correct wire as the hot! If the earth wire is used as the hot for the wiring in a house such as an outlet, an electrician may touch that wire thinking its just the earth wire and it doesn't carry any voltage. However because it was used as the hot the electrician would get shocked. I hope you understand how dangerous that is to wire incorrectly.

[@yurikocraze1019]

Hot wire or not, consider all lines are live at all times , The main reason he should use proper color coding is to practice good practice for future.,

[@intensecutn]

​@@yurikocraze1019Exactly. For someone to get shocked by this would mean that two people have done the wrong thing. Two holes in the Swiss cheese were aligned. Treat them all as if they're live until you've confirmed that they're not.

[@SamFitClips]

this man single handedly made it possible to control basically anything, thank you, you truly are a great person for sharing this.

[@kondenzo]

This is very dangerous what you are showing to people. Everything is superb but the part, where you are using the yellow and green wire for L (phase) is very dangerous. The correct way is ALWAYS black, brown or read for phase “L”, blue for neutral “N” and yellow-green for GROUND. Please remember that because you are showing people how to connect voltages and currents that are very dangerous. When electrician comes to you to fix the some kind of problem, to him is normal the color scheme that I wrote and if he would touch the yellow-green wire he would get killed or heavily hurt. But anyway thanks for tutorial and sorry for my bad English.

[@kengaming789]

where do i find the manual for that? i need to have valid references for my paper...

[@expert20valvehlx]

Are you sure that ALWAYS is like that ? If someone is electrician he will test if there's voltage before touching wires and there is huge banner in video itself, so please shut the fuck up!

[@stienogamez8296]

kondenzo fuck off, nothing wrong with it, if and electrician is working on it he always has to measure it

[@mitchelll6359]

Trusting color schemes is dangerous. smh.

[@Marcin-fx6hz]

There is grounding in plug and socket - on sides of them (its German type Schuko), so yellow-green should be connected to them. And please don't ever use Green-yellow for power supply! It kills people... Every electrician knows to not use it this way. Those who don't know are dead or in jail!

[@DonDennisDTensta]

hey, good idea, but you have to use the green yellow wire for earth and the Brown for switching the bulb on/OF , the blue musst be connected directly in both ends.

[@jumbo999614]

So removing yellow jumper allows you to use adapter to provide 5v to relay and protect your arduino board from frying?

[@johnmarks714]

Thanks for demonstrating this module with high voltage. It was hard for me to believe that relay could handle high voltage, even with the markings saying so, until i saw it.

[@johnwilson3918]

Nicely presented video! I don't know what country you're wiring for. I think it's important to point out that you're switching LIVE or NEUTRAL through a wire that looks like it's colour coded for EARTH. In the UK , wiring standards dictate that the YELLOW/GREEN wire is EARTH. I'm sorry if I missed something in your presentation but I couldn't hear you tell us - what line (LIVE or NEUTRAL) you are switching. You most certainly should AVOID switching the NEUTRAL wire. AWLAYS place your switch (i.e the line 'break') on the LIVE ('hot') wire. Thank you.

[@DavidJJJ]

You are correct as others have mentioned you should never connect power this way with earth, he is using the wrong wires.

[@screeningstudio3868]

Hi, one question, if we use Active Low module relay, the the green led light will constantly light up, does it mean the circuits is closed? Im kind of confused different between Active Low and Active High trigger, for Active High, the circuit is constantly open right? The green led light will not light up until we sent a 5V signal from our controller trough PWM pin right? Please correct me for better understanding between Active Low and Active High trigger, thanks a lot 😁

[@rawfreshoner]

How would you connect the 120VAC to the relay if it were a 3 terminal high voltage wire? I assume the "live" wire would be connectect to the COMMON terminaal on the reay. and the Ground wire would not be cut from the chord, but what would you do with the neutral wire?

[@nfsking2000]

I don't get why you use PE wire instead of hot wire...

[@DavidJJJ]

Others have mentioned it but yes, it’s extremely dangerous and not recommended.

[@mlee6050]

Does it need to stay connected to a PC to work and how to power it? I want a guide for say bidet is being powered as in using power that it disable an air con on same plug to socket connection

[@snowboyyuhui]

Why is the DS1 diode required if the optocoupler has an LED in it pointing in the same direction? Is DS1 just rated for bigger currents?

[@respectandcare-e7g]

Hey, Could you pls explain the reason why a relay could have its normally open pin stuck and always closed. I ended up damaging 2 relays out of a 4 channel 5V relay module when turning off/on my laptop charger. However the relay used to control my speakers and monitor is working fine. Now I am not using other relays to control laptop charger fearing to lose another. What should I do?

[@Ali-k1213]

Great Video. Thank you SO MUCH for sharing the basic functionality of Relay with the circuit diagram.

[@farooq9861]

Great video sir I've understood the working of relay

[@sandysandilya3852]

sir for a single channel relay , there is no JDVcc . There are only three pins for vcc , In, and gnd . What should I do now. Please reply.

[@kennmossman8701]

JDVcc is the same as Vcc

[@brianford6729]

Excellent video! I bought a cheap 2 channel relay with no model number or schematic. The explanation in the video and the schematics were very clear. I'm impressed with the little module and the optocoupler for isolation is very nice. Thank you for the video.

[@danieldavila5585]

Dejan, do you have to put digitalWrite(in1, HIGH) in void setup? Does it not work if you just put it in void loop?? I am just not understanding what is the purpose of including this in void setup

[@2112user]

Question I've got is on the power supply. I'm in the "making the sketch" phase of my design with some parts wired up. I would like to put my circuit in an double gang electrical box with 1/2 for low voltage and the other for high voltage (with outlet). I am looking for a small and cheap 5vdc power supply, but wondered after seeing this... would I need 2? Could a back feed from relay to power supply harm the Arduino (nano in my case) if the nano is drawing 5vdc on USB to power? Last question would be.... have you found any small, good and low cost 5vdc supplies to use in compact projects?

[@markalansmithuk]

Do you have the earth/ground pin connected between your mains plug and socket? It looks like you might not - and you definitely should.

[@yahoobolt]

Now I realized the use of jumper in jdvcc thank u man.

[@Sorcli]

Also for this application, if there is a short circuit on the lamp, does it cut out?

[@joshuavincent7884]

why do you need a second diode after the optocoupler if the coupler contains a diode of its own

[@wellofbeersheba]

I take it that the issue with the separate power for the relay is that if there is a short inside the relay, power from whatever device is connected will go shooting up the 5v line into the Arduino and kaboom: smoke and melted plastic. If this is right, what are the chances of it happening and could you put an appropriate diode on the line to stop it? I am a bit of a newbie so sorry if this is a dumb question.

[@wellofbeersheba]

+Dejan Nedelkovski Thank you, thought I would ask!

[@clockdoc36]

Thank you just saw this video that's for the clear pics of the ac side of the relay. Now I get the proper way to connect the switch

[@sanjayrajure]

Which software did you use to draw the circuit diagram at 3:47. I could not find electric wiring and adapters in Fritzing.

[@ratnatekchandani4421]

sanjay rajure download from other third party sources.

[@patfacunla1687]

I LEARNED A LOT. THANKS FOR MAKING THIS LOVE IT

[@oceanofgaming]

Never cut the earth wire. Brown and blue is for live and nutreal and yellow and green wire is for earth

[@kabandajamir9844]

So nice the world's best teacher

[@jeranrai645]

hi there, this is normal situation of turning on and off the devices, is it also possible to control the intensity of light and speed of fan using this method ! ?

[@kennmossman8701]

no

[@MrSikkandar]

if i want to create a finished product, i cant give separate power supply to micro controller and relay, then what will be the solution for that ?

[@GrayCo]

A great video that forces one to think about the circuits. Everything in the video was done safely and exactly as it should be expected. It is entirely entertaining reading the comments below. Some of those comments really reinforce the old adage - "a little knowledge can be a dangerous thing". When in doubt, put an oscilloscope on the circuit and learn something new.

[@samgarcia9521]

great detailed video. the only thing you forgot to mention in your video is the the relays have input and output terminal. i saw you had a phone charger rigged as an input for the relay. i loved the way you explained the schematics. 9/10 presentation. i dont know if this tutorial is geared for begginers.

[@samgarcia9521]

+Dejan Nedelkovski correct but you still need a source of power to go into the relay and out to the component you want to power. you never mentioned this in your video. for example if you were doing and electrical outlet you would do the same thing you did with your setup but in this case you use the same power cable interupted by the relay if you were doing a home

[@samgarcia9521]

+Sam Garcia what i mean is you didnt make your power out of thin air . i see you have a surge protector as you power source you have your phone charger plugged into it thats you input to the relay. and the output would be to your light bulb ,heater,lamp

[@samgarcia9521]

+Dejan Nedelkovski great job overall ty so much

[@jervx829]

I'm Coding using PY & GPIO on rpi 4, I'm new to Relay but I just check this video out because I'm so confused when I try the relay & send signal as low the relay LED comes on while sending high turn the relay off. Good thing I watch this so now i understand it is reversed. Does all 5v relay work this way (Low-On, High-Off)?

[@steventan5414]

HI mate i made a similar setup but instead i used an AC socket(outlet) connected to the relay but everytime the relay is triggered (i.e. turned off bcos the socket is connected to the normally open interface), the arduino shuts down why is this happening?

[@sriharshareddy2096]

It was an informative video. But, I don't have a ground right next to the JD-Vcc pin in my relay, can I connect the ground of the 5V power source to the other ground pin which is along with IN1, IN2 pins? Kindly clarify. Thanks

[@Omnicurious]

I have similar 4 channel relay with a removable jumper between JDVCC and VCC, however, I only have one ground pin. Does this mean my relay can not be isolated?

[@6uiti]

Great tutorial , simple and elegant. Saved me alot of time

[@joegyebi7496]

I dont find the gnd for the VCC- only VCC and jVCC? Where is it? HW-316 relay...

[@phoenix2464]

even if the micro-controller is connected in parallel with the 5v power supply will it still be in danger from the relay ?

[@Budget_hotels_India]

The code giving compilation error...'in1' was not declared in this scope

[@mpikkt]

hi, i need to connect 6 relays, how should i connect the 5v from the arduino to the relay board?

[@dannylumcreative]

Amazing tutorial! Thank you so much

[@malikattaurrehman4723]

i m using this relay module for home automation project using IOIO OTG but this relay module is operatin by giving grnd of ioio to chnl 1 or chnl 2 WHY ??

[@raeesmuqthar7991]

Good work with great clarity

[@philipmurray4065]

i have one more question. can i connect a 12v adapter to JDVCC? i have that one for now

[@thabisoedwintjatjie5339]

Sir Dejan Nedelkovski, I'm working on a project that uses solar power to charge laptops for students so I've decided to get an Arduino micro-controller + coin acceptor + a board of 8 relays. So i want to make sure that when a student insert a coin to the coin acceptor, the coin acceptor will send a pulse to the Arduino micro-controller and the arduino will active the relay for a certain time in order to allow the student to charge their laptop for that selected time. So how can i connect the coin acceptor to the Arduino so that the relay activates when someone insert a coin to the coin acceptor? Please help, if possible you can help me with the codes for this operation.

[@thabisoedwintjatjie5339]

+Dejan Nedelkovski Alright, thanks.

[@blueckaym]

Hey guys, can I use this hl52s SSR AVR as a smart-switcher in a DC-UPS ? I mean to make Input-A preferred (the one from the Power supply plugged in the wall socket), and Input-B linked to a battery. So that when the PSU is unplugged /or there's power outage/, to automatically switch to input-B without interrupting the work of the end-device (in my case Intel Skull NUC mini-pc)? If not, can you recommend me such smart-2INs-1OUT-switch that supports input voltage 19~25V and max current of 8A?

[@freemanfreed1581]

I would like to control the direction of 220 V rated 0.12 Amp DC motors using raspberry pi . I have tested it on RPI using relay to switch ON and OFF and it works fine . but to reverse the direction of this large motor ,I should have use motor drivers . I have L298 in my hand . can I use L298 for this purpose?? how do i use both the relay and the L298 together??

[@kennmossman8701]

a DC motor rated at 220V?? perhaps use two SPDTs

[@auditocanarsie7355]

Why did you choose the Arduino Mega board? Couldn't you do the same thing with the much smaller Arduino Pro Micro board? I understand the video is 7 years old.

[@far-red]

Good, I was thinking about how do we wire up relay to microcontroller and your video showed the practical implementation, thx

[@psalmsofplanets0722]

Hey Dejan, why couldn't you simply use a diode to jump the Vcc pin to the JDvcc pin? Wouldn't this protect the microcontroller from any induced current and send it to ground?

[@carlbarlev]

The purpose of removing the jumper and using an external 5V supply is to provide isolation. If you use a diode there would be no isolation. You would also lose the voltage drop across the diode, which may affect how reliably the relay circuit operates.

[@psalmsofplanets0722]

Carl Barlev My thinking is this though: diodes allow electricity to pass one way to a certain extent, so if you power the relay (assuming the voltage drop is small enough to allow the relay to work) with the arduino 5v rail through the diode, it would prevent any electricity spike from going to arduino and would instead go to ground. Am I wrong? Isn't that the entire point of a diode? Sure, technically it's not 100% isolated but assuming you aren't getting a 100v spike or a huge amperage, it would prevent the backflow which could damage the 5v rail. Would it not?

[@carlbarlev]

A diode would provide some protection, but not as good as isolation. The problem is that the voltage spike caused by back-EMF when the relay coil is de-energized can be hundreds of volts... the diode could fail short and expose the arduino to the voltage spike. Using a free-wheeling diode across the relay coil allows current in the coil to dissipate without creating back-EMF. Free-wheeling diodes are thus only exposed to the normal coil voltage, not the voltage spike that would be caused by the back-EMF it has avoided.

[@psalmsofplanets0722]

So if I manually solder in some free-wheeling diodes to the relay board I would be good? Is it that simple? I feel like if it were, the circuit designer would've included them for a few pennies more.

[@navedsyed9354]

good idea given by carl barlev about the diode should be used free wheeling. connect between the relay coil

[@mcdrivesltd8518]

Am I missing something. Should you also connect the Ground (GND) of the Arduino (next to the 5V) to the GND of the relay board?

[@HowToMechatronics]

Yes, that's correct, you should connect the Arduino and the relay GND(the low voltage side).

[@kennmossman8701]

@@HowToMechatronics technically I believe you do NOT have to - kinda defeats the opto-coupler

[@drrobotsir]

No, the output pin on Arduino will sink the current

[@crispychickenwing]

how to connect the adapter to the jdvcc and ground of the relay?

[@samridbudhathoki1853]

Nice Tutorials bro. Explained in detailed. Awsome :)

[@rosssonnycruz9695]

can i connect this without having an external 5v adapter?

[@othmanehammam8893]

i want to control a 24v dc mtor what should i do for the high voltage part ??? thanks for your help

[@Aalsobiae]

Is there any way to power the arduino with 5v without using the usb cable? Because i want to fix it outdoor and I don't need to exchange batteries every period of time. I hope get the answer.. So many thanks

[@Aalsobiae]

Dejan Nedelkovski could you please show me how? Any KZbin link may help. Thank you so much

[@DrumBeat231]

Which of the two wires in the cord do I connect to the relay?

[@davewalters9926]

Any idea why i can get my relay to work with my arduino is powered by a 9 volt battery connected to VIN, but when i connect my arduino to a 9 volt plug in type power supply (actually sending 9.2 volts to the VIN), the relay doesn't work properly? ...it sticks "closed" (LOW) and won't disconnect? There's an LED connected that turns on when the relay switches on ("Closed"/LOW). The LED stays on too. What is going on?

[@kennmossman8701]

your power supply is rubbish; either bad waveform or not enough current or voltage drops too much at full load

[@kararsabih3910]

Great one .... Is it necessary to connect both the Vcc & JDVcc??!

[@dominikkkkkkkkkkkkk]

karar sabih yes

[@Gruby100T]

Great tutorial. I base my final year project on your tutorial on touch screen and this one, plus some sensors tutorials from other sources. One question. What software do you use to write circuit diagrams in this video? they are very clear...

[@TTGTanner]

In the wiring diagram, why is there no ground connected on the right hand side of the relay?

[@kennmossman8701]

????

[@johnjcb4690]

What use the transistor has , emitor to Gnd?

[@himu-mn1dr]

Can I use 12V 1A adapter to power up the Arduino Uno ?

[@LemonTreeNOTfree]

int in1 = 7; void setup() { pinMode(in1, OUTPUT); digitalWrite(in1, HIGH); } void loop() { digitalWrite(in1, LOW); delay(3000); digitalWrite(in1, HIGH); delay(3000); }

[@Zekedog1]

Thanks for the tutorial, I am going to use the information you provide, however, I would like to know if the arduino would use standby voltage and run my power supply down.

[@pauldecastro1523]

what are the caseS (relay malfunction) that can happen to the relays connecting using arduino 5v and what is the worst caseS can happen to the arduino if the relays using arduino 5v supply malfunction?

[@kennmossman8701]

per 3:12 nothing would affect the uC relays can fail in a few ways..............

[@akroutsamo]

For me i don't Know what is the purpose behind Low trigger Relay but it is simple to inverts them by connecting the IN1 to GND and the VCC off the relay module to a digital pin of an Arduino , the JDvcc to a 5V power

[@malavpatel77]

I had a question, I have had a touch time finding relays that can work uptill 30A DC, but at a lower voltage of 12V. Would these work for my case?

[@kennmossman8701]

use a SSR

[@Ziplock9000]

Thanks for being clear about the optoisolator and why it's there.

[@ChrisWilson999]

Had to go through a dozen or more videos and or articles to finally get a great one. Thank you!

[@nithishsaran7519]

Hey will the vcc from relay power the arduino

[@dasdunetechnologies1695]

Nice video! please, could you tell me what is the cad software used for your line diagram of the relay ?

[@Malhar]

can I power the Arduino from the same source as the GDVcc???

[@sahilshukla8127]

MEndeavour yes you can power arduino from JdVCC but if something unusual happens then it damage both , the power supply & arduino

[@Yass120o]

excuse me when i remove the jumper and i put an additionnal power support 5V i dont know why it doesnt work for the same channel module

[@Yass120o]

+Dejan Nedelkovski actually finnally it worked perfectly.. i've forgot to connect the gnd of the external power supply and the gnd of the arduino toghether :P thank you verymuch !! bigup !!

[@SunnyWu]

There is one part I don't get. If the Arduino isn't sharing a ground with the relay circuit, how is the signal passing through. My circuit skills are a little rough, so I didn't quite get it.

[@Nobody-yt7yz]

is the yellow wire for the voltage?

[@leanderpereira5257]

Hello can u please tell me how to connect the extension board with the relay module

[@ricardobjorkeheim775]

use the brown cable (phase) instead

[@yoramstein]

hello Dejan. How do get the fading? The relay can go only 1or 0 (connect/unconnected) and I cannot see any Triac in the circuit? Do relay rotate?

[@timkoufogazos2621]

That is the camera compensating for the change in brightness (auto-exposure)

[@markrity]

I did not get why we should connect the 5v adapter to relay module and not get that 5v from the board? while the 5v adapter connected to the board? Explain please if you can :)

[@markrity]

+Dejan Nedelkovski Ok now I get it , I have 2 more questions , 1)I think that UNO will be fine for a small project like this , is that right ? 2) Where I can get an adapter like in your video? Already with pins or should I just make it myself?

[@markrity]

+Dejan Nedelkovski Thank you for fast answers ! P.S. I really liked this video , so you got yourself a new Sub . Keep the good work and good luck!

[@tobotdolce9556]

sir it is possible to use this module if i plug a aircon or a refrigerator? thank you for your response

[@kennmossman8701]

the relay is rated at 10A given inrush current, could be used for up to 500 Watts for an inductive load look at using a SSR

[@zonic6094]

Hi sir, great video.. is there a way to put a dimming circuit that ranges from dim to bright..

[@zonic6094]

+Dejan Nedelkovski Do you have a design that i can use as a basis to produce lamp with dim and bright function. I will be very grateful for your help and advice.. :)

[@zonic6094]

+Dejan Nedelkovski okay, thanks :)

[@VacancyJB]

hi, why need a separate 5V supply? the Arduino 5V output should be ok right?

[@kennmossman8701]

the inrush current of the relay may affect the UC or related circuits

[@jembola7474]

Nice video. I'm doing ARDUINO water control system using AC motors. Main components include LCD display, ultrasonic sensor, 4 channel relay unit, AC Submersible water pump(8W). Without the Ac power the LCD display works fine. But when the Ac pump is driven from relay unit after the circuit on for some time the LCD display goes MAD. displays different kinds of other characters and keeps on going. Any suggestions. Thanx in advance

[@clipped6446]

power issue

[@Sorcli]

Great info. Could this also be used as a 12v fuses box, so if one was running 12v devises it would protect them?

[@inquisidiego]

not at all. This is not a fusebox. It's a relay. If you try to use it as a fuse box, and exceed the rated current, then the relay will stop working as intended. Maybe it will still work for high currents, maybe it will short the connections, maybe it will break the connection. You don't know. A fuse box is made to cut the connection when the rated current is exceeded. It's used as a safety mechanism.

[@AndrewPena76]

Great video...I’ve been driving myself crazy trying to figure these out. I’m working on a garage door opener with he Particle Core processor, Blynk and these relay’s - it’s supposed to work on iOS.

[@tejasjadwani9414]

Hi this is really cool vedio get good explanation of relay activation on low. I have questions 1) what if the Arduino board power off, in that case does it sense the low on pin and relay activate or not? 2) how to configure relay activate on high do we need different relay module for this?

[@woopywoopwoop]

If i enable optoisolation i.e power my relay board through external supply , should i connect the digital ground pin of arduino to the GND pin to the right of the digital pins on the relay board ?? what will happen if i do that ? do i loose the optoisolation ?? how does that happen ?

[@kennmossman8701]

I wouldn't connect

[@yusufmazlan2334]

@DejanNedelkovski Can I use this kind of system to control a bigger machine like a single conveyor machine?

[@kennmossman8701]

use a SSR

[@cprn.]

Can you control those relays separately? I.e. two devices on and off independent of each other? Or does this turn on and off both relays at the same time?

[@sumedhburbure4173]

Yes, the relays can be controlled seperately. Both relays can be turned off and on separately independent to each other's state.

[@anandjoshi8554]

@@sumedhburbure4173 can this Arduino micro controllers perform complex logic as done by plc ladder logic ? I have a 4 dc output and 3 ac output (0.2 - 9 amp) small project plus 7 dc input, with washing machine/traffic light type logic.

[@sumedhburbure4173]

@@anandjoshi8554 Yes it can be done using arduino.

[@anandjoshi8554]

@@sumedhburbure4173 which board plus components , i need to buy for that many input /output, except the relay ? if u can help that ? (as I am a electrical engg, with little knowledge of electronics !!) i myself had already prepared sucessfully my plc ladder logic in two months (from learning to sucessfully preparing it) and about to order PLC @ 8000!!. i think, i now have to learn Adriuno coding !!🤔 to save cost and space in my project !!!

[@anandjoshi8554]

@@sumedhburbure4173 would Adriuno's programming hold when power failure happens and resume ?

[@6uiti]

One question tho , Should i connect the blue wire to the relay

[@jeffreyjbyron]

Love the video. If I just wanted to toggle between two 220v lamps, would I need a unique program to run the arduino? Or could I use it's default setting? I.e., use a momentary switch to control low voltage to the relay?

[@kennmossman8701]

why use a uC?

[@wasibilgrami2364]

I have only Two way channel in my switch board. How can i connect + / - wires in this case? Please help

[@murarimahto6274]

how can i use it in a ultrasonic sensor setup to run 24volt motor?