Jbeale shared his tiltmeter project in the forum: Apparently the most popular sensor for this purpose is an “electrolytic tilt sensor”, basically a bubble level with internal electrodes. These are not exactly consumer items. I tried building a simple pendulum tiltmeter using a split-photodiode, Optek OPR2100 (about $10 from Mouser) and LF411 opamp. The pendulum […]