I’ve got Deta C3501 which is 230V doorbell, very popular in UK. No converters or stepdowns.
I used the Shelly PlusI4, its cheaper than Shelly 1 and it works on 230V.
It’s not the best looking solution , i didnt really feel creative to make this shine. Anyway…
L from mains to L on Shelly
N from mains to N on Shelly
L from bell to L2 on Shelly
N from bell to SW on Shelly
configure SW1 in shelly as switch. thats it
Before:
After:
