I'm designing a two-part computer input device: Part A will communicate with the computer over BLE, but it must also be able to forward along messages from Part B. Here's an illustration:
Computer <---BLE---> Part A <---???---> Part B
What would a power efficient strategy for them to communicate with each other? The data rate would be a few kilobytes / sec, but latency would need to be < 50ms when the device is being used.
My inclination is to use BLE, dynamically adjusting the connection interval to be shorter (to reduce latency when the device is being used) or longer (to save power, when the device is unused). But since I control both ends (nrf52 devices), are there any other protocols I should be considering? E.g., would Gazelle provide any benefit here?
This is my first wireless project, so I don't have any intuition about the marginal power reduction a custom protocol might provide over BLE. I already plan to use the DC/DC regulator and low frequency crystal on my design.