Which part of that system is connected to wifi? I guess kinetic energy from the bell can be enough to send a zibee message

Nonsense, complete over engineering. I have a door, and people knock on it.

I have an overengineered wifi doorbell, and I've yet to have a delivery where it was used over knocking on wood.

I haven’t had a delivery person knock in quite a long time. Package deliveries haven’t knocked in close to 20 years. I’ve even noticed DoorDash drivers don’t even knock anymore, they awkwardly stand in front of the porch and try texting. I now open the door as they are walking up to the porch to avoid that. I don’t know if it’s a policy or some kind of shared anxiety, but I find it really weird.

I had one food delivery driver call me while standing in the middle of the street. Seemed like he was afraid to approach and knock or ring. So strange.

Some people get really weird if you approach their house in a way they don't like. I imagine if that happens a few times to you as a delivery driver, you might be more cautious.

> would assume if they ordered a delivery that the person would be expected and not a cause of alarm

The problem is they've probably gone to the wrong house before and met an owner who got defensive.

Do you perhaps live in a place where people answer the door with a gun in their hand?

Seriously. Everyone that id want to actually press the button just pounds on the door. The door to door people in particular have figured out they can’t be easily told off.

I used to live in a small rural city, in a shared house where the door was never locked. On market day, there would be this woman coming in to do her weekly laundry. I was never given the key to that house.

Two wires and two C cells? Careful, someone is going to put a subscription layer in front of that

"Only works with Juicero brand C cells."

I can squeeze off-brand C cells by hand.

Is it still easy to get C cells? I probably would've used an 18650 or some AAs.

Current delivery and longevity still put C and D cells over AAs, that’s the main reason they are/were common in doorbells. And while 18650s would be equivalent to a C, they would require a charger most people don’t own already, as well as the usual liion safety issues. I’ve heard horrors of folks putting 18650s in to nimh chargers with sprung terminals :/

As for availability, they are certainly very obtainable where I am in UK. Shops and Amazon etc have them.

No issues here in UK. 18650s have high self-discharge rate so are useless for standby applications. AA's are, well, AA's. So you'd have to replace them more often. Not what you want to happen with a door bell.

I use adapters for AA cells. It's just a plastic tube the size of a C cell that you snap an AA into. I have to replace them more often but I use rechargeable AA cells so waste is not an issue.

I would want my light switches to be off when I click a special button at my bed, so when I want to bed I "turn off everything, and make sure garage is closed". Unfortunately two wires don't work there.

Wow two wires? Sometimes people could make do with only one!

Nah, for light switches I'm all-in Philips Hue because it's both pretty and convenient. Plus LEDs synchronized with that via House Assistant.