BLE Custom Service & Characteristics UUID

Official Hardware Retired 101
1

Hi,

After some read on BLE protocol, I understand that we can have general 16-bit UUID or you can have custom 128-bit UUID.

But how do I define them ? Any number ?

For example in the LED example:

BLEService ledService("19B10000-E8F2-537E-4F6C-D104768A1214"); // BLE LED Service

// BLE LED Switch Characteristic - custom 128-bit UUID, read and writable by central
BLEUnsignedCharCharacteristic switchCharacteristic("19B10001-E8F2-537E-4F6C-D104768A1214", BLERead | BLEWrite);

How the numbers are been defined for custom UUID ? I understand that for characteristic is just add 1 at the end of the 19B10000.

Any tips for Curie BLE ?

THANKS !

Vincent