In our multi-appartment building we have an old doorbell system (1970s) from Koch (Model K933UP). My goal is to be able to open the main-door from HA without modifying the existing system too much.
I started based on the following project: https://www.reichelt.com/magazin/en/build-smart-doorbell-arduino/
I used a D1 mini board with a relay shield as ESP and configured it appropriately with ESPhome.
As I use a 18650 battery as power source, I put the ESP into deep sleep when not in use.
Once the bell rings, the D1 is woken up from deep sleep and connects to wifi (which happens quite fast). However it takes some time till HA connects again and you can control the entities via HA. Is there any way to speed this part up?