That looks great thanks for sharing!
Is that a HC-SR04 you are using as a distance sensor?
The buttons look good and smooth (despite the fact that one of them was not working, alas!), do you have a link to the product page?
Do you get to use the built-in speaker? Is that a passive speaker powered by Bela?
Just one minor correction on your pass-through latency figure;
assuming you are using analog input to audio out, you have:
- ~1 ADC sample conversion delay
- ~1 samples transmission (SPI) delay
- 32 samples due to the dual buffering (16 samples per buffer)
- ~1 transmission (McASP) delay
- 21 samples DAC converter filter group delay
That adds up to ~66 samples, that is - at 44.1kHz - 1.5ms.
If you use the audio in, then you get 17 samples group delay in the ADC, so that makes for a total of 82 samples. so 1.9ms!