How can I write to the my keyboard device driver I will create?

I would like to build a Bluetooth keyboard for a smartphone like this product.

This product has a hardware driver. Ho开发者_如何学Gow can I write device driver for my keyboard.

---

You don't need to write a driver if the smart phone already supports bluetooth keyboards. If it does you just need your product to support the bluetooth HID protocol.

If the phone doesn't support bluetooth keyboards, it sounds like your question should be titled "How do I write a keyboard device driver for Windows Mobile?".