ESP32 Read time/date from iOS device via BLE Bluetooth

Using Arduino Networking, Protocols, and Devices
1

Dear community,

I need to read the actual time/Date from an iPhone via BLE.

Background:
This is a kind of retrofit clock for an oldtimer car (BMW E30). The origial Clock is not useable anymore as we did a significant change in the entire car structure (including the change to an V8, 4ltr engine).
The idea is to have a new BC/Clock module but based on an ESP32 and a 2" display. Also including the reading/writing to the K and I Bus.
And I try to make it for an universal solution.

THe question is: How to get the correct time. I thought about
a) the start at home with WiFi and a battery buffered RTC module - Disadvantages: WHen the Lithium Batteris empty, there is a need to remove the complete BC unit, which is cumbersome and when this happend abroad, than there is not chance to set the time again; this is only a solution which works for a single user, as there is too much hardcoded parameters.
b) the connection via iOS hotspot and setting via internet time. Disadvatages: see above.
c) a standard BLE connection to an iPhone. THis could be done by any user, this is in my opinon a universal solution.

My question: How to read the time/date from an iPhone after the BLE connection is established.

Many thanks for your thoughts and hints.
Willythecat

2

ONLY an iPhone? It can take years to get Apple to approve an app. I am not sure how/if this can be done. I hope you have done a lot of google searches.

3

iOS does not expose a standard BLE service or characteristic for retrieving the system time or date. If you need to access this information via BLE, you do this through a custom BLE service implemented by a specific app.

Might add complications to your "simple for everyone" requirement and if you don't want to code, there might be apps out there to do something similar (like
‎Clock Sync App Blue dans l’App Store)

May be your ESP32 could offer a captive portal experience. Join the portal from your smartphone (does not need to be iOS) and a UI pops up where you can enter the information required.

Probably some security measures would need to be added so that this does not get abused

this GitHub - tzapu/WiFiManager: ESP8266 WiFi Connection manager with web captive portal could offer the basic building block you need.

4

Here is a thread where someone else wanted a similar set up.
https://forum.arduino.cc/t/receive-actual-time-from-bluetooth-connection/637121

5

I got the simple idea to use a GPS module. Much better and more fuctionality.
THX
Willythecat

6

That is a good idea. If you use the car battery for the GPS power source the builtin rechargeable battery will last many years.