Smartening up my doorbell

Hardware
1

(Continued from here)

Hi all,

I currently have a simple mains powered doorbell chime running on AC:

current%20bell
current%20bell964×266 11.7 KB

I have three features that I wish to add to it:

  1. To generate a programmable notification when it is pressed
  2. To be able to programmatically mute the chimes
  3. To be able to programmatically trigger the chimes

I also have a few fundamental requirements: the system should fail to a usable state (ie the doorbell triggers the chime) if the “smart” bits fail, or if the internet goes down.

After a bit of research I’ve found the basis on which this project can be built:

https://github.com/tIsGoud/Doorbell-via-Wemos-and-optocoupler

Which I believe should take care of the first requirement. I now have a few questions, some general to wemos development and some specific to this project.

  1. I see that there are various Wemos D1 boards, including what seems to be a new D32 model. Should I just go for the latest and greatest, or is that overkill and possibly not yet mature? Or is there a totally different board I should consider?
  2. Apart from the circuit components, what accessories do I need with the board? I see various shields and the like, do I host the circuit on the “bases” (single double or triple?). Or do I use some kind of separate breakout board? How would that be interfaced to the pins etc?
  3. I see there are shields with relays in them which I would have considered for a simple on/off usecase. Is it still worth using them for my slightly less trivial project, or should I use my own components?

I’ve come up with design adapted from the github project above:

simple%20wemos%20with%20mute%20v3
simple%20wemos%20with%20mute%20v31152×648 5.8 KB

  1. For the “switches”, would I just use simple off the shelf relays (taking care of NO/NC per instance), something like this?
  2. Do I need any other components (eg for safety/regulation)? I feel I’m missing a capacitor or two ;). What should the resistor values be (or how can I calculate that?).
  3. Is a wemos stable enough for me not to be paranoid about failure and, and to just have a button sensing circuit, a chiming circuit, and a wemos running software in between?

Assuming the above works what else should I add to the shopping list apart from:

  • 1x wemos (or equiv)
  • 1x 2 channel relay module
  • 1x optocoupler
  • 1x diode
  • 1x 330ohm resistor
  • development items (breadboard, power etc)

Any thoughts appreciated!

2

Plus a power supply for the wemos?

3

Oh of course. And I suppose the relays should have their own power too. I was planning to run the wemos using USB though.

Do you have any advice on what material/platform/board I should build this circuit on and how that would interface with the wemos?