DIY Door Bell Push Notification with ESP32 (trigBoard) Full Tutorial

Part of a series of videos on monitoring everything with the trigBoard! The door bell is an obvious one to add IoT to and one of my favorites. Just note that this was installed in my house, which may be different from how your doorbell is wired... make sure you fully understand how everything works and only make connections when the power is off.
This project is documented here parts/schematics/etc:
trigboard-docs...
Tindie link to trigBoard - options to add boards to build exact cellular based system as shown in video: www.tindie.com...
Thanks to all the Patrons for dropping a few bucks in the tip jar to help make these videos happen!
/ kdarrah
Twitter: / kdcircuits
For inquiries or design services:
www.kdcircuits...

[@FrankGraffagnino]

very cool. would like to see an update where you power the trigboard from the doorbell voltage to get rid of the battery!

[@Kevindarrah]

yea, only problem is that case when the button is just tapped, you wouldn't have enough power to wake, connect to WiFi, and send the push notification.

[@FrankGraffagnino]

@@Kevindarrah maybe the unit could be installed by the transformer instead and the circuit could detect a current flow instead. then you would always have power.

[@szaszafaja]

you could trickle charge the battery through the bell coil with a low enough current so the bell does not get energized. if the bell buttons wires are accesible it should be pretty easy.

[@n1kkri]

@@Kevindarrah This is very close to what I was looking for. I don't have any programing experience and this doesn't require any. I was thinking of a current loop detecting current triggering a device to send the sms or email message. How often do you have to charge the battery? That's the only negative I see. The service you use to send the text message, would that be a free service or pay for?

[@n1kkri]

@@szaszafaja Maybe a resistor across the doorbell button to allow some current flow??

[@wadefallin]

Another awesome project Kevin! Great tutorial on how this works as well!

[@atomikrobot300099]

This will be my next ESPHome project! Thanks for the idea!

[@Kevindarrah]

cool, let me know how it goes!

[@Mathias1234]

I used an voltage divider (with resistors), connected between my doorbell and my ESP8266. Works great, probably unsafe, but a 1000 times cheaper and super simple

[@radnukespeoplesminds]

This is what i thought of doing too. I thought maybe it would be worth using an op amp follower and fuse tho

[@n1kkri]

Could you please go into a little more detail on how your voltage divider circuit connects to the circuit? Thanks

[@Mathias1234]

@@n1kkri Sure, here's what I use. VIN (from the button press, 7.2v) R1 in my case 1k VOUT (to ESP8266 12-E ADC pin in my case, now 0.978v) R2 157 (odd, I know, I combined 100+47+10 in series) GND (this is both the doorbell & ESP's GND). This gives me 0.978v out, on my 7.2v power source. But there are tools online for generating the R1 & R2 resistor values, so you can take the 16V as shown in this video down to something you can use (3v?), with whatever resistors you have laying around. Search for "voltage divider calculator". And if it's AC, as used in the video, you might want to add an diode bridge rectifier to be more safe (remember LED's are also diodes, so you probably already have all the parts needed). I have however sensed both AC and DC with my ESP, so I'm not sure if you REALLY need it rectified.

[@relali2009]

Good video, just wondering why did you use a single diode rectifier vs full bridge rectified signal. Since you are using 2 caps after diode you may not notice the ripple when missing the negative side of your AC signal.

[@anthonytamalonis]

‘Doorbell text message’ and ‘buy trigboard’ were added to my todo list last week. You just saved me a lot of work! Could you install this at the transformer instead of at the chime? I guess for your method you need to take your input from after the button and before the solenoid? Could you put an inductive coil around the 16V ac wire at the transformer and use the current measurement to activate the trigboard? Would potentially be non contact, but not sure if it would work or how reliable it would be

[@Kevindarrah]

hmm, yea I was thinking about that as well... maybe I'll have to experiment with this

[@n1kkri]

I was thinking of the same thing. I have seen small clamp on current sensors but they have been used to feed ESP32xx boards to send out the sms or email message.

[@OkOtChA]

Hey Kevin. How much will this project differ if the door bell its just a "buzzer" and not the "ding dong" thing. Thanks

[@DarrahValentine]

This is very fascinating I wish I understood it all but great smart idea

[@chrisw1462]

@4:12 Your single diode is only a half-wave rectifier, so you only get one side of the AC, and half the voltage. In your case, a little over 11 volts is all your capacitors will see. Without a center-tapped transformer, you will not get the continuous pulses you drew. Every other pulse will be missing. If you had used a bridge rectifier (4 diodes), your numbers and drawing would be correct. And, of course, you'll never get 12 volts out. Your regulator will sit there doing nothing except passing the full 11.x volts on to the relay.

[@nyckid]

Why not just put a N/O door contact (or raw reed switch like you started with) on the solenoid of the doorbell and save the voltage regulation gear to power the project off the 16vac instead of a battery?

[@Kevindarrah]

actually, I did try this, but didn't work as well.

[@nyckid]

@@Kevindarrah The sensor or power? An inexpensive accelerometer would also be able to feel the movement of the solenoid.

[@tornadokat]

I'd think a 12VAC coil relay would be OK on a 16VAC transformer for the very short time it is actually energized... not enough time for the wire in the electromagnet to heat up and burn out.

[@amcomma]

That's awesome, but why use ESP32 for it and not cheaper ESP8266?

[@ursmii_]

because he sells the trigboard on tindie. get it?

[@PhG1961]

Great ingenuity !

[@billiejean3748]

Have you noticed a relationship between solder flux left on boards and increase in sleep current, in your general experience

[@Kevindarrah]

only one time, but not directly... I heard there were some board failures and that it was due to a "dirty board". I guess they cleaned it up and it worked. I have never seen this issue before though with anything I've done, but then again, I always clean my boards pretty good with alcohol. That might be a good experiment though

[@billiejean3748]

@@Kevindarrah i had battery powered boards in the field that underperformed the calculated battery life by a couple months. Then I learned that flux is conductive and that isopropyl alcohol was a thing.

[@Kevindarrah]

@@billiejean3748 yep, that's how I clean my boards! But might be cool to test this though

[@neooooooooooon]

6:51 may i know what is this thing called? and 10:24 the gold thingy below also

[@Kevindarrah]

yea see description for link to the project page - everything you need is there

[@neooooooooooon]

@@Kevindarrah yeah im sorry i didnt see it first

[@n1kkri]

Would a reed relay or the type they put on doors placed near the solenoid relay of the Chime close the relay to fire off the trigBoard? I tried this but the round relay I have could not fit in the area or the solenoid relay. The slim type would fit if I had one.

[@Kevindarrah]

yea, I actually tried that and some success, but wasn't 100% reliable, so I moved on. If I had to do it again, I'd use an optocoupler circuit instead.

[@n1kkri]

@@Kevindarrah what about a small current probe to detect current when the doorbell was pressed. You could also mount this anywhere you had access to one of the doorbell wires. My transformer is at the circuit panel. I also have a a.c. receptacle near by I could use a cell phone power supply to power the trigboard.

[@smitcher]

If you are going almost the full way in electronics then why not just stick a optoisolator after the smoothing caps with a resistor feeding it... Would the output of that not be sufficient? More compact circuit than having a relay... Also, wouldn't having it wake-on-open mean that if someone held in the button constantly then the trig board would never trigger and i suppose those annoying folk who hold it in for 10s then the trig wouldn't boot until the end of that 10s rather than the start...

[@n1kkri]

Is there a free alternative to Pushover? Is it possible to send email instead of text?

[@Kevindarrah]

yep, IFTTT, Push Safer, or even MQTT to your own setup. All supported by trigBoard in the base firmware

[@n1kkri]

@@Kevindarrah I was under the impression that Pushover was a paid for service. I will have to look the others up. Thanks

[@n1kkri]

@@Kevindarrah when you say "to your own setup" you mean just entering my router user name and password? Do you also offer a way to communicate to the trigBoard via a simple AP access point method like many other devices like Honey Well WiFi Theromostats and other DIY projects? Would having to have Windows 10 then not be so important and it all done via WiFi?

[@FrezzaArmy]

You could just use a sound sensor und place it when ever u need it near your door 🤔

[@n1kkri]

Wow, I just looked up how much the cost is for the board. If this was a $5-$10 board it would be a good deal. At $30 plus the rest of the parts, might put you up at $50 at least with shipping I have been looking at projects using the ESP32xx boards which seem to be priced much lower but require programing. Has anyone converted a existing product like a water sampler with wifi sms or texting to work with a doorbel?

[@Kevindarrah]

Yea, small batch manufacturing in the USA is not going to be cheap - not to mention the endless development time that goes into this sort of thing

[@n1kkri]

can I use my cell phone for the bluetooth connection for configuration? If I use my laptop will it work with Windows 7?

[@Kevindarrah]

mobile support not yet... working on that, but really need Windows 10 for the configuration - not tested under win7

[@n1kkri]

@@Kevindarrah Well that kills the project for me. I don't have any plans in the near future to move to Windows 10 while everything I am doing now works fine with 7. Will check in once in a while for updates. Thanks,

[@Kevindarrah]

@@n1kkri if you got a raspberry pi laying around, that works too

[@n1kkri]

@@Kevindarrah I do have a spare Raspberry Pi. Do you have an image I can put on a SD card and a wiring diagram for it?

[@Kevindarrah]

@@n1kkri oh I mean you just need that - use chromium to go to the configurator link: kevindarrah.com/configurator/

[@yogeshitaliya473]

Nice onw

[@harveyellis6758]

using an optocoupler would be simpler

[@ffoska]

yep. I don't like the relay solution either...

[@electron-1979]

My first and last plan!

[@Kevindarrah]

didn't have any optos handy, but I've got another project in mind that I'll have to try this method out on

[@studiociodo]

Pc817... You can find It on ANY switching Power supply...

[@normcaissie5598]

This channel is nothing but trigboard commercials. Don't get me wrong they are cool but not at those prices.

[@Kevindarrah]

yea I know, but lots of trigBoard projects here to share - you're probably not going to like the next couple vids.

[@normcaissie5598]

@@Kevindarrah I was a new sub so this is all I've seen so far.

[@kikmedown]

I'm really impressed with how your trigboard has progressed. Will this board work with push buttons to wake it up? I am curious to know if it would work to attach to an intercom call/buzz button. Or even multiple buttons.

[@Kevindarrah]

yes, this is possible, needs a little circuitry/programming, but no big deal - we can chat on Discord if you pick one up

[@kikmedown]

@@Kevindarrah great! As soon as I get back home, I'll get to it. Thank you

[@kikmedown]

@@Kevindarrah just bought one. About to join discord