Raspberry or OH found it? Do you see this device in PaperUI? You may need to turn on “simple mode” in Configuration>System>Item Linking for OH to discover it.
If using the RPI 3’s built in bluetooth that will work but range may be limited.
I use a RPI 3 with buletooth and followed this https://community.openhab.org/t/3rd-party-bluetooth-binding-beta-testers-needed/38492?u=h102 guide for setup.