How can raspberry pi and relay switch can communicate over bluetooth.(No wire between relay and raspberry pi)
What is your hardware?
What bluetooth relay do you have?
Currently I have a Raspbery pi 3 with Openhab2 installed and REES52 DC 5V 8 Channel Relay Module.
Currently my Relay Module is not having bluetooth. I want to understand what is need (hardware) to this working.
Don’t use bluetooth, use wifi.
Use an ESP8266 module like the wemos mini: https://wiki.wemos.cc/products:d1:d1_mini
These module have a wifi module inegrated and multiple GPIOs
They can be easily programmed with the Arduino IDE:
And there are many, many tutorials on how to activate a relay using the module, OH and mqtt: