I made a bike brake counter using a linear potentiometer and had fun building it. My uno checks the pot and when triggered by position change, writes date-time and value out to a SD file. The potentiometer is mounted along the bike top tube and clamps the brake cable with a brass wire stop nut. Easy to put on - take off the bike frame and no problems with brake interference...but my uno-SD hardware needs a better case and battery mount. I've not analyzed my data yet - other than to check that the numbers seem valid. My intent was to gather data to predict "brake pad wear" - not likely to happen quite yet, but good fun just getting the data so far.
