I am trying to use Bluetooth Binding for connecting a Generic Device with Gatt characteristics in OpenHAB. I am using temp sensor with ESP32 and Sending value using BLE-GATT. But by using this binding I am unable to see the temp value except RSSI strength.
The Bluetooth binding doesn’t work with any arbitrary BT device. According to the docs, the BT binding only supports an RSSI channel by itself. Nothing else. To get other information you have to install one of the listed extensions (separate add-ons) such as Airthings, Govee, Ruuvi Tag, etc.
I can see no extension that supports GATT so I doubt it’s supported.
So Can I write a seperate program in JS and give input using a Toggle wizard to send signal to bluetooth-ESP from Openhab-Raspberry Pi?
I don’t know what you mean by “a Toggle wizard”. But bluetooth is a low level wireless protocol. The format of the messages sent over BT though is not defined by the standard. Each vendor and sometimes each device implements their own message formats and other unique details with the traffic. There is no such thing as a generic “button press message.” That’s why the Bluetooth binding has so many extensions. Each extension knows how to communicate to that vendor’s devices.
Without an extension all the BT binding can do is see that specific BT devices are present and their signal strength. If you need more, you need a binding extension written that knows how to talk to that specific device.
If you write something outside of OH that handles all of the BT communication and which can send and receive messages to/from OH in a format it understands (e.g. MQTT) that could work. But all the BT stuff will then be implemented outside of OH.