according to the example of Erel, BLE (Bluetooth Low Energy) should be supported starting with android 4.3.
I am currently trying on my old Nexus 7 with Android 4.4.4 and the sample says that BLE is not supported.
Does anyone know the problem?
yea that is the issue. Your Nexus 7 may only have Bluetooth 3.0 hardware in it. There are 2 versions of the Nexus 7. 2012, and 2013. Only 2013 has the BT4 hardware.
Also, BLE is an optional part of BT4. Just because box or specifications say BT4 (or 4.0 or 4.2), doesn't guarantee the device supports BLE. No prizes for guessing how I found that out.
BLE Checker (by Michael Yan) is the easiest way to confirm BLE hardware present.
And if it is, then +1 f0raster0 re Nordic Semiconductor nRF Connect app. I tried a few, and thought that app was the best for connecting to and exploring BLE peripherals.
https://de.wikipedia.org/wiki/Bluetooth Bluetooth 4.0
Die Spezifikation 4.0 wurde am 17. Dezember 2009 verabschiedet. Mit diesem Standard wurde erstmals der Protokollstapel Low Energy verfügbar
Bluetooth 4.0
Specification 4.0 was adopted on December 17, 2009. With this standard, the protocol stack Low Energy became available for the first time