Schematic design critique

[Skyland]

I designed a schematic for my project and I'd be thankful if you could give me any feedback on it.

I'm specially looking for anything wrong or inefficient with my circuit.

The purpose of this project is to read data from the accelerometer, perform signal processing and output an alarm sound if a certain behaviour is detected.

 

[ads-ee]

You're not following the recommended decoupling for the ADXL345 see page 28: https://www.analog.com/media/en/technical-documentation/data-sheets/ADXL345.pdf

 

[ArticCynda]

I agree with ads-ee, it's recommended to add a secondary decoupling cap to the ADXL345.
Further remarks:
- Make the UART pins (30 and 31) external on 4 pin header together with VCC 3.3V and GND. Having a communications port aside from ICSP is always useful for debugging.
- Add a filter before the buzzer and drive it with a PWM signal instead of a square wave to remove the high pitch noise and make the sound more "natural". Ideally, choose an active filter with a rail-to-rail opamp like the MCP601 to avoid sourcing the drive current for the buzzer with the MCU.