search

asterics / esp32_mouse_keyboard

ESP32 implementation for HID over GATT Keyboard and Mouse (Bluetooth Low Energy). Including serial API for external modules (similar to Adafruit EZKey HID)
GNU General Public License v3.0
788 stars 111 forks source link

BLE - GATT transmission rate limiting #37

Open benjaminaigner opened 4 years ago

benjaminaigner commented 4 years ago

On some phones (currently observed on one older Android device), the received GATT HID reports are processed slower, which leads to noticeable delayed movements.

A possible solution would be a rate limitation for sending GATT data.

Open for discussion:

Relative data (mouse movements):

Should we discard received UART HID data if sent too fast OR should the ESP32 sum up mouse movement values & send them accumulated in one report?

Absolute data (mouse clicks & keyboard keys):

I think these should be sent ASAP (when the rate limiting timeout is finished), without further modification.

@ChrisVeigl what's your opinion?

benjaminaigner commented 4 years ago

Implemented both, behaviour can be changed via make menuconfig or idf.py menuconfig. See: https://github.com/asterics/esp32_mouse_keyboard/tree/rateLimiter

ChrisVeigl commented 4 years ago

Should we discard received UART HID data if sent too fast OR should the ESP32 sum up mouse movement values & send them accumulated in one report?

Absolute data (mouse clicks & keyboard keys):

I think these should be sent ASAP (when the rate limiting timeout is finished), without further modification.

wow - you were so fast implementing this i could not even add my comment ;-) great that both options are available now!

i agree that keyboard reports and mouse clicks should not be discarded - but sending them ASAP could also lead to problems (e.g. a mouse clicks at a wrong position). accumulations of relative data is IMO the best method and should be the default.

i added a PR with some comments: https://github.com/asterics/esp32_mouse_keyboard/pull/39

maybe we can now remove the rate limiting which exists in the FlipMouse code: https://github.com/asterics/FLipMouse/blob/56b854f2b889f4f2fac8f5503f65db2b070b8f90/FLipWare/bluetooth.cpp#L66

For this, we should integrate the rate limit settings of the ESP32 into the UART command protocol (to make it accessible from the host system / GUI).