I'm trying to calculate the distance between 2 devices using various methods with the given limitations:
- Speed is a huge factor, therefore, authentication / handshake process is a bad idea
- Must be valid for at least 20 meters
I've so far came with the following solutions:
- Bluetooth - From my understanding, is going to consume most of the battery, distance is limited and authentication is mandatory(pin code)
- Audio frequencies - I know there is a solution by google, but couldn't find anything valuable
- Wifi - For this solution, one of the devices must be configured as a hotspot, is it possible to run a lite-weight hotspot service on both sides which would skip the authentication process, wouldn't offer any internet connection but simply broadcast its existence and signal strength