From the docs:
“ESP-NOW is a kind of connectionless Wi-Fi communication protocol that is defined by Espressif. In ESP-NOW, application data is encapsulated in a vendor-specific action frame and then transmitted from one Wi-Fi device to another without connection.”
https://docs.espressif.com/projects/esp-idf/en/latest/esp32/...
Edit: this video discusses power consumption of esp now: https://youtu.be/6NsBN42B80Q
[edit]: This is assuming you are connecting directly to the device of course. Connecting the ESP32 to your existing wifi is well supported and much more reliable.
If you could return valid internal DNS entries for these domains, and serve up a 204 to the right requests, you should be able to stay online.
You need to ensure you don't do it for every possible domain - I believe Chrome also tests random non-existent domains too, to ensure it gets back the expected error.
What is not working fine though, is that I cannot access the internet through the mobile network at the same time. But this seems to really depend on the phone: it works on iPhones and on my previous Android phone, but not on a Pixel 5. I would like to download updates for the esp32 firmware through the mobile network, but this prevents it.
If power is your concern, have you considered nRF5 devices? Nordic has a proprietary profile for sending serial data over BLE (NUART) but AFAIK, you could only connect to one device at a time (not many).
I'll look into the nRF5. I've been using some of Nordic's code to test and build my prototypes already, although I feel like adding a proprietary profile on top will just make it harder to interface. Once I make the connection currently, all I need to do is enable notify on the specific characteristic which isn't too complicated (just a lot of code to actually get the characteristic)
https://github.com/NordicPlayground/nrf52-ble-multi-link-mul...
Although I do wonder whether wifi would be a better technology to use sometimes. The only thing I remember seeing is that wifi technology uses much more power.
From TFA it looks like WiFi 6 uses less power, is this true?
Anyone experienced have any suggestions whether BLE or WiFi would be better for streaming serial data from a device onto many platforms? (I currently have a BLE demo working, but working with Bluetooth stacks on mobile and desktop are a royal pain, network requests are very straightforward at this point)