The previous comment noted that "phones have [suitable sensors]". Duplicating those in the board would work, but even then - checking every 10 ms will mean a fa

The previous comment noted that "phones have [suitable sensors]". Duplicating those in the board would work, but even then - checking every 10 ms will mean a far higher battery drain (and yes, we've just complicated everything at least one order of magnitude, this point still stands).