Today, I found a strange phenomenon that my Android device scanned fewer devices when I turned on bluetooth compared to my mobile phone. Therefore, I want to improve the scanning time to obtain as many detected devices as possible. But I looked it up, and someone said it involved the Bluetooth protocol stack. I'm confused. Can someone help me?
There's a few things that may be going on here.
Firstly, your phone may not be showing devices it cannot support. For example, certain devices may not be meant for phones to connect to, so are not shown in the list of one device, but may be shown in another.
Secondly, some Bluetooth devices do not broadcast/advertise themselves to other devices, which may cause it to show up on one device and not another.
Most modern phones will continuously search for Bluetooth devices while you are on the Bluetooth menu, but I don't believe that time will be the cause of the difference in the list of devices.
There are some apps that will show all the Bluetooth devices around you, including some more hidden devices or unsupported devices, if you don't want to program your own.
If this is for some kind of app, let us know what language or device you are targeting and we can provide some language-specific support.