DIY Smart Switch - Part 2 Motion Activated Relay

[@maheshbabu552]

All doubts solved in 1 video. Excellent!!

[@48-inchlevel74]

I loved the demo of EveryCircuit simulator at around 5 minutes.

[@Aaku13]

Hey, love the video. Just some advice from someone who 3d prints a lot. You made your walls super thick. I probably would have done .5mm on each side maximum. This will save you tons of print time and filament.

[@bytesizedengineering]

Good to know, thanks! I'll have to experiment with wall thickness. I usually leave that on the default cura setting.

[@jacobkeller29]

I’m looking to do basically the same thing. I want to light up strips of leds hung under my kitchen cabinets, so they’ll light up the counter top when I walk into the kitchen. Would be excellent!

[@utrutr6013]

Music is kind of loud but great info and well presented. Great job 👍

[@therealb888]

Much better than the first video, liked!

[@maryannemacalinao8376]

Thank you so much for a very informative video about using relay module

[@chrisgicky2215]

Thanks for taking the time to do all this

[@bytesizedengineering]

Thanks for taking the time to watch and comment!

[@ammaribrahim5756]

you're logical and awesome....

[@paulmcgrath2000]

Very clear and informative, keep em coming.

[@allcartooninhindi7640]

I use is on my Almira to turn on the light when I open.

[@m3rdpwr]

When you were testing the threshold of the relay, I was looking around my office to see where that clicking was coming from. hahaha

[@bytesizedengineering]

You're welcome ;-)

[@varunsv5891]

Absolutely Loved it!

[@itlife4555]

Very valuable knowledge for me to learn about relay.

[@Sabre00]

Love the design but to make it more sustainable you can put a small AC to DC power supply inside the enclosure and have that use the mains power to power that the PIR and the relay (low side). You can put a main switch at the back for the AC to the power supply) and one at the front ( as you have it for the DC to the PIR and relay. That way you don't have the power supply on all the time if you are worried about power consumption.

[@bytesizedengineering]

That's a great tip. I considered doing that, but wanted to keep it simple for anyone wanting to make one. Do you have any recommendations on an off the shelf transformer/regulator? In the past I've just bought really cheap USB wall chargers on ebay and ripped them open to steal their AC/DC power supply. I would like to find one that is project friendly.

[@Sabre00]

A simple off the shelf phone charger AC to USB block. They are 5V @500mA or more which is more than enough to power the PIR and the relay. Usually the square blocks have a low profile circuit that can probably squeeze into your battery pack part without any print changes.

[@ChristopherGraham13]

This is something I want to see. I want to do an in wall light switch with one of those power supplies so that I don't have to change batteries. My wife keeps losing the timer for the holiday lights and I wanted to convert the plugs out there as well. For things like this plugs, switches, outlets, anything that I could tap into the mains and make it permanent I would like that option. I don't want to plug in my light switch.

[@mrnutsy1]

Like the design and information. Only issue is that the music is a little loud for the vocal levels on the video. 😬 Keep making the videos! Like what I’ve seen so far!

[@bytesizedengineering]

My apologies, I finished editing really late last night, and should have been more careful with the volume levels. Thanks for the feedback, and thanks for watching!

[@kelvinkersey5058]

Really really good and clear, thanks. (too much loud music). I'm working on switching a 12v valve using a normally closed relay to cut off the water from the water butt when the bucket is full. Next I want to make bird scarers to hang in the fruit trees. Any thoughts would be appreciated.

[@bytesizedengineering]

Those sound like great projects! See if you can document your process and share with others!

[@SachinKumar-js8yd]

Great video.. Nice explanation. Keep making such videos. Subbed!!

[@JeffKirkley]

Nicely done! Very impressive. Really liked the 3D printer and your approach of making this!

[@michaelhenderson5098]

Enjoyed the video (except for the music). Now get out there and design the auto start for your dust collector. I could use one...or two. One for the miter saw, and one for the CNC. Both have shop vacs collecting the dust and chips. Currently I use a simple remote to start the shop vacs which isn't too cumbersome, but auto is better in my opinion! :-)

[@bytesizedengineering]

Thanks for the feedback! I'm trying to find time to work on more of these projects. The shop vac auto switch is near the top of my list. I just got a new table saw that I want to add dust collection to. Stay tuned, and thanks for watching!

[@relaymatik5984]

You can use latch relay Like i did i install in bathroom if you enter in bathroom the light on and if you go out light turning off i set time in 3seconds its cool

[@Mr_Gadge]

Loved it thanks, but please, lose (or lower) the music! In some parts it's as loud as you. I don't need entertaining I need educating lol :) thanks again.

[@WKellyJW]

Thank You for the Videos. I have already increased my knowledge in just a short time by watching your videos. I always wondered why someone would need a 3D printer, now I see how useful it is. I always used a roll of electrical tape to seal my projects. I am working on a rear window defroster in my truck since it did not come with one. I am going to try it using Conductive Copper Foil Tape 1 inch for the BUS and 3mm for the lines.I plan on using a NE555 DC 12V Delay Relay shield Timer Switch Adjustable Module to turn the power off after about 5 minutes. Do you have any advice

[@bytesizedengineering]

Thanks for watching! Your defroster project sounds cool! Let me know how it goes.

[@francispoblete9660]

It would be nice to see this integrated into an internal clock of a vehicle to turn on a led emblem for a vehicle. When you drive your car at night, it would light up the led emblem on the front or back via relay.

[@amtpdb1]

It would be best to cut the hot side of the extension cord wire as you would with any switch. Thanks for the video.

[@bytesizedengineering]

Thanks for the tip, I actually made sure I cut the hot side of the extension. The extension cord I used has ridges along the length of the neutral side to help with identification.

[@brightgarinson3099]

6:15 Is that little piece your soldering a resister? And if so is it required?

[@fairjusticeguy5648]

Hi Zach, how do you run the wire to test the relay with the variable power supply and the oscilloscope. I have the Rigol Dp832 power supply and Rigol Ds1074z. The leg that is connected to the resistor and Vcc, is it the drain leg? and the leg to out is the source leg? Thanks

[@leytonjay]

This is brilliant. I have a PIR I can use with a relay, but I also WiFi relay I want to use with my Google Home, any tips? Thank you.

[@keithryant5779]

Very Nice!

[@electrosync]

2:19 Mmmmm, that slo mo action...

[@veseloiu]

Actually, my understanding is that the relay turned ON with voltages ABOVE 3.9V, and it was OFF, with voltages between 0 V and 3.9V so the relay would be OFF all the time, NOT ON OR, where did I get it wrong? A relay with no power applied to it, (0V) is OFF. A relay with not enough power applied to it (3.3-3.4 V) i.e. below the voltage threshold is still OFF and a relay with enough power applied to it (i.e. above 3.9V will turn ON (For clarification, I am not confusing power with voltage but the threshold is in volts , as the relay does not use that much power anyway So, I think that your diagram at 4:19 and the subsequent comments that the relay will turn on with any voltage below 3.9 V is wrong. The relay will NOT turn on with any voltage below 3.9 V that is the relay coil attracting the blade. The relay will normally have three contacts, one is common and then one is NO (normally OPEN) and one is NC (normally CLOSED) When you power the relay with ABOVE 3.9 V, the relay will turn ON and the NO contact will become CLOSED /linked to Common and the NC contact will become OPEN (disconnected from the common)

[@taufiqlee6144]

Hi Zak, thanks for the video. However, I'm a bit confused on how the relay works. You mentioned that the relay will remain close when the voltage output from the sensor is below 3.9V. So my question, is that not the right outcome if what we are trying to do is whenever there is a motion detected, the sensor will output 3.4V and causes the relay to close hence completing the circuit and result in the light being switched on? Why do we still need the mosfet? Sorry for the lengthy questions

[@bytesizedengineering]

Good question, I tried answering this with the graphs in the video starting at 4:00. You're exactly right, when the motion sensor detects motion, it outputs 3.4V which is low enough to turn on the relay. However when the motion sensor stops detecting motion, it outputs 0V, which is still low enough to turn on the relay. In this case the relay will always be turned on, and never turn off! The motion sensor will just keep sending either 0V or 3.4V which is never enough to turn off the relay. See video at 4:15. In order to turn off the relay, you need a signal above 3.9V. So you need a signal that switches from 0V to 6V for example. I need the relay to turn on when motion is detected and turn off when motion is not detected. The mosfet fixes both of these problems. It translates our 0V-3.4V signal to 0V-6V and inverts the logic. I hope this makes sense.

[@whc2001]

The relay is low-level triggered, which means every voltage below 3.9V(logic LOW for relay module) will make it turn on (close the relay). However the PIR sensor is high-level output of 3.3V, which means it will output 0V(basically GND, logic LOW level for the PIR module) when it's not triggered, and output 3.3V(logic high level for the PIR module) when it's triggered. As their logic level definition of HIGH and LOW is different(the PIR sensor is 3.3V logic while the relay module is 5V) and their enabled level is different(relay is LOW enabled and PIR is HIGH enabled), there must be some convertion. Sorry for the long and unprofessional answer and hope it can help you understand further.

[@adityaharlalka9173]

hats off to u ..i love with ur video

[@m3rdpwr]

Question, since you were using this to control A/C power, did you consider building a small power supply to fit in the case? (Or take an old USB charger out of it's wart case.) You could have utilized the A/C Power in the box and avoid the batteries. Just a thought.

[@bytesizedengineering]

This is a great suggestion. I did consider both of those options. In the past I've ripped apart old cell phone chargers to get the 5V AC/DC power supply but this was a messy solution. Since this video I've found off the shelf 5V AC/DC power supplies that should work well for projects like this.

[@svenbosma5704]

@@bytesizedengineering I am trying to get my light switch to work via wifi and then homekit. This project is kinda finished but one thing, i have an esp8266 hanging out of my light switch, powered by a phone charger plugged into an outlet. I want to get the esp8266 in the wall but i dont know if it is safe to use my ripped appart phone charger and solder the mains onto it. Is it safe for me to do it, can my house burn down and is this a good overall solution?

[@genesams993]

Awesome vid!

[@azimalif266]

Isn't there a jumper on the pir sensor to switch between the on or off trigger?

[@lucky6147]

Please make a DIY on RFID based garage door opener which opens or closes for only the given car

[@bytesizedengineering]

Wonderful suggestion. I will put that in my project idea list!

[@gadflyberlin1]

Thanks for the great videos! I am not sure if the previous responser is correct. The MOSFET to invert the logic might be what I need. I thought I could use the NC and NO to solve my light triggered relay. I have a relay to close the door buzzer for my building. The relay has an optical sensor taped to a screen of an old phone. Idea being: friends want into my building, I am not home, they call a number and the building, door is open. Door should be open as long as the screen on the phone is lit. Problem being, if the relay has no power, the normally open is closed, only with power is NO open....all fine.....phone call lights screen, door buzzer circuit closed all fine ...EXCEPT.... if my 5v supply to the relay dies (USB transformer...they do die) the circuit is closed and the buzzer will be buzzing permantently. Not good. Will likely put a sonoff relay AFTER the optical relay. there has to be a simpler way. Free accomodation in Palma de Mallorca if you can help me.

[@bytesizedengineering]

Sounds like a cool project! Good luck

[@gadflyberlin1]

@@bytesizedengineering since discovered IFTTT. Missed call from guest telephone number ID will trigger Sonoff in inching mode (3seconds). Only the caller ID from the guest will open the door, when I remove that number from the trigger, they no longer have access. I love the Sonoff 4ch and 12v SV switches since they allow inching mode and have NO/COM/NC relays as opposed to the standard Sonoff switch. Thanks for your inspiration.

[@pzb4]

interesting video. thanks. i'd like to hook this to a handicapped door switch to automatically open doors when someone walks toward it.

[@bytesizedengineering]

That is a perfect use for these PIR motion sensors. Let me know if you implement this, I'd love to see it.

[@pzb4]

Can you tell me what is the little gold part you're soldering on at 5:59? is that in my official arduino kit or something I need to buy? i don't see anything like it in my kit. is the 9v battery adapter ok to use or should i get the AA battery adapter?

[@Lionheartgrudge]

Thanks for this awesome video. I have a really quick question, relay doesn't depends on the frequency, right? Or do they come with a frequency rating?

[@bytesizedengineering]

I'm assuming you're talking about the frequency of the AC current coming out of the wall (50Hz or 60 Hz)? No, they don't usually have a frequency rating.

[@Lionheartgrudge]

Thanks. I figured. This video helped me so much. Keep up the good work.

[@jacobkeller29]

Is that the Anet A8 3D printer? That’s what I’ve got. I’ve been learning fusion 360 by watching Lars Christensen. He gives live tutorials, and has lots of great videos in his library to learn from.

[@bytesizedengineering]

Yes, it's the Anet A8, I did a video about it as well. That's great that you're watching Lars for some Fusion tutorials! He's really helpful, I've watched lots of his videos. Good luck!

[@jalpapatel15]

Awesome video. :)

[@Ali_zee_x]

Inspiring

[@therealb888]

Link to the music tracks used in both your videos on this project please?

[@dougneel1193]

Great Vid! Can you help with a RV control project of mine? Love to here your thoughts? Take care,

[@0el0baku0]

How much time does the AA batts will work? I was thinking to do a project like this for a walk-in closet lights

[@bytesizedengineering]

The batteries should last quite a while. The more time the relay spends turned on the more power is being used, and the sooner the batteries die. You could use a cell phone charger to plugged into the wall to provide power instead of the batteries. That's what I would do for a more permanent installation

[@romkaizeris]

Hey, Zak, I'm thinking of creating SonOff type switch that would have a physical button (possibly touch type), motion (PIR) sensor and WiFi switch all together. What do You think of this challenge? :) BR, Romas.

[@arrowstheorem1881]

Cool channel !

[@bytesizedengineering]

I'm glad you like it!

[@grannyspeachtea7764]

The logic part completely flew over my head. And that damn music in the background. Appreciate your effort. But could you explain better the Logic gate etc part of this for NooBs like me?

[@bytesizedengineering]

Digital electronics use 2 different voltages, usually zero volts and 5 volts or whatever the battery or system voltage is. These two voltages are used to send on/off, high/low signals. Some devices are activated with a low signal and some are activated with a high signal. Sometimes a device produces a high signal when you need a low signal. In this case you need to invert the signal to make it low. That's what I needed to do to get the motion sensor to send the right logic level to the relay. Without this "inverter" the relay would do the opposite of what I wanted. Hope this explanation helps!

[@spaceagemonkey8451]

do you think if I use arduino to control the PIR sensor and hook it up to a light (connected to a relay) i would avoid having to go through all that complicated procedure of soldering other micro components to my sensor?

[@bytesizedengineering]

Yes an Arduino could absolutely be used to do the same thing. I wanted the challenge of not using an Arduino. I'm glad you're thinking about other ways to do this, that's always cool to hear!

[@randomyoutuber4500]

someone with electronics knowledge pls explain this... Why do we need a MOSFET and all those ? if we just amplify the signal to around 4V and use the 'NORMALLY OPEN' port with the common, switch will be closed when the signal gives a 4V & Switch will be opened while the signal gives below 4V. that way you don't have to deal with that reverse logic. I think there was a reason why you didn't do so. if someone knows it, pls explain...

[@cww.2051]

What amperage does this support again?😁

[@bytesizedengineering]

Thanks for the trolling CW, I guess that's what friends are for!

[@allinone555666]

what transistor you use npn or pnp?

[@bytesizedengineering]

I didn't use a bjt, instead I used an N channel mosfet.

[@kiddybuddy1601]

I am a beginner. Any N channel MOSFET will work?

[@nimraaslam6760]

hi sir, i want to On and off power supply to arduino automatically using relay is that possible?

[@lostspace5811]

Hey would it be easy to switch the light off when the sensor gets triggered?

[@bytesizedengineering]

I answered your question in my reply to your other comment on my other video. But here it is again: That sounds like a cool project! I see that you found my other video showing the PIR motion sensor. I would start with something like that and connect it to the normally closed terminal. Good luck!

[@lostspace5811]

@@bytesizedengineering thanks i looked up relay wiring and yeah i get the different wiring to normally c or o thanks. Glad it is easy :)

[@itlife4555]

I still don't understand The electrical circuit between Relay and the sensor. I need to check again.

[@RSuarez66]

What mosfet did you use?

[@bytesizedengineering]

I think I used a 2N7000. Very common, should be easy to find on eBay in a pack of 10.

[@lostspace5811]

How long does it stay on?

[@bytesizedengineering]

Since there is no microcontroller (like an arduino) the only way to adjust the time is right on the PIR sensor. There is a potentiometer that controls the delay time.

[@donutactual8887]

Can you show us how to connect to a raspberry pi zero from a distance using another raspberry pi. For example I want to control a raspberry pi zero from 5 miles away

[@bytesizedengineering]

I would connect them to the internet. You could run a web server (Samba) and have the other as a client.

[@Lionheartgrudge]

I am trying to do the same. I am gonna use an IoT to control the switch manually and remotely. They are really cheap and there are tons of resources on how to use them.

[@iamalantam]

hi your amazon affiliate link is not working can you provide list of items to purchase?

[@bytesizedengineering]

I'm sorry the links aren't working. I'll try to fix that ASAP.

[@vikramodedra4351]

Nice work , would share 3d printer file, I don't have 3d printer so can order it

[@bytesizedengineering]

I normally would share the 3D stl file, but this was a really rough design. If I get around to polishing it up, I will share it with you.

[@jacobkeller29]

Instead of using batteries to power the sensor couldn’t you use a wall wort that produces the necessary voltage. I think that’d be a more permanent solution

[@bytesizedengineering]

That's certainly a good option.

[@peter-e2q]

Uses...? For me, to trigger something scary in my loft when a mouse pops in at night!

[@bytesizedengineering]

That's a great idea!

[@jay-tbl]

Why don't relays activate when you put in voltage and deactivate when you have no voltage, not the other way around? Seems counterintuitive

[@bytesizedengineering]

The coil in the relay behaves exactly as you said. Most of the time these little relay modules use a transistor to drive that coil and depending on what type of transistor they use (NPN, PNP, N channel, P channel) the logic to turn on the transistor will be inverted.

[@drew2308]

Considering using this to trigger a fog machine for 10 seconds once motion is seen.

[@protektosafe]

FWIW, we don't watch your videos to watch your soldering technique. I would recommend you double the speed at that point. If people really want to watch that part closely, they can slow the speed to half with the player. ------- A suggestion of course. I also suggest you break out some parts, such as 3D printing a cover. This will give you extra material at no extra cost. It also give more people a reason to come. You then get electronics, home improvement, & 3D printing.

[@bytesizedengineering]

Thanks for the feedback

[@aniszed3641]

pleas sir can you send me circuit diagrame ? tnx

[@bytesizedengineering]

Sorry, I don't have one for you. I try to document everything I can on my website, but this one didn't make it on there.

[@eduardoquiroga1494]

this whole time I thought was going to make something with a scream activator when i walk i to the room the lights turn on

[@thomasedonovan]

Zak, get some safety glasses!

[@Olleroy]

and the code!!!

[@bytesizedengineering]

There is no code in this build

[@AShadeOfYou]

Zac is there a private message here on YT? I couldn't find one and I wanted to ask you something.

[@bytesizedengineering]

I have a contact form on my website www.bytesizedelectronics.com/aboutcontact/ or you can email business inquiries to contact(at)bytesizedelectronics.com

[@sharank]

Bit of constructive criticism, that rock music was very distracting and made it impossible to focus on the instructions

[@NeverStopSeeking]

Can not believe you do not know that relays like that one have a normally open and a normally close output! Would have eliminated the need to test and make the new circuit to use it!

[@bytesizedengineering]

Thanks for the feedback. I'm fully aware that relays have NO and NC terminals, in fact I mention them in part 1 of this series. There are two reasons why I can't use the NC terminal for this project. First, as I mention in the video the output of the motion sensor ranges from 0 to 3.4V DC. It doesn't have a high enough logic level to activate the relay, if I were to directly connect the motion sensor to the relay, it remains closed all the time even though motion is being detected. I have to have a signal that changes from 0 to some voltage over 3.9V. That's why I used a 2N7002 N channel mosfet to get an inverse 6V signal out of the 3.4V motion sensor output. The second reason I didn't want to use the NC terminal is the fact that this is battery powered. In order to turn off the lamp (the state it would be in 95% of the time), I would have to energize the coil which would run down the batteries much quicker. The coil would be draining the batteries most of the time just to keep the lamp off.

[@trentwiewel2456]

@@bytesizedengineering great design! for a while I was wondering why you didn’t just use a transistor to amplify the 3.4 volts to get the relay to switch from NO to closed. But that would of taken more components than your design that used just three. Thank you for sharing

[@rmhutchins7]

SUGGESTION: Get rid of the annoying background noise (music ?)! You have too much information to offer -- don't make it hard to understand you.

[@bytesizedengineering]

Thanks for the suggestions. It's always hard to balance how much technical information to get into. Some viewers want a lot of technical info, while others get overwhelmed by any technical info. It's something I'm working on finding the right balance.

[@stevengray188]

I would have appreciated not having the distracting music as I find it difficult to concentrate on instructions while being brainwashed by music.All I can remember now is ding ding ding ding ect. I am a male who can only concentrate on one thing at a time . Great video other wise.

[@bytesizedengineering]

I'm still learning how to make/edit videos, thanks for your patience. If it's too bothersome, you don't have to watch the video.

[@AmmarTee]

Music is too Loud...!! and Unnecessary .

[@toldt]

I can't hear what you're saying because of the damn music. Get your priorities straight.