[DesiLurker]

makes me wonder what if I just wanted to sync with nfc every once in a while. wifi seems overkill for this. maybe it could be done much cheaper with nfc sync witha phone twice a year?

[phh]

An ESP32-C3 Super Mini can be found for below 3$ (cheapest I had was 1.58€). Since the original clock is 3.88$, it can't be that much cheaper.

[pantalaimon]

You often have a radio clock source like DCF77 that all those radio controlled clocks use

[yjftsjthsd-h]

ESPs are so cheap that you couldn't possibly save very much money, and the way economies of scale work it may or may not be cheaper to use NFC anyways.

[sowbug]

We've been shopping for a simple bathroom clock to replace our final Amazon Echo and leave that increasingly dystopian ecosystem. There are some models that use Bluetooth on your phone to sync the time. I could imagine BLE being a good low-power and relatively stateless solution. But given our goals, we're not going to install an app on a phone just to maintain a wall clock. (I'd be fine if Android provided BLE time sync as a built-in service.)

[russdill]

Home assistant has pretty good BLE capabilities. But honestly, as has already been pointed out wifi is already really cheap.