3 ms·
Perhaps a strain gauge (https://en.wikipedia.org/wiki/Strain_gauge https://en.wikipedia.org/wiki/Strain_gauge), a primitive sort of accelerometer that has been
by abraae 9y ago
Perhaps a strain gauge (https://en.wikipedia.org/wiki/Strain_gauge https://en.wikipedia.org/wiki/Strain_gauge), a primitive sort of accelerometer that has been around for donkey's years.
- consp 9y agoIf it is a ball it probably is a ground plate on the bottom and top with sense connector plates on the edge of the box where the ball is in. The ball moves around and if it gets a connection (ground to sense) a counter gets increased and a time gets reset and since you are moving the thing usually moves around and make some connection when braking/accelerating/steering. You need bumpy roads though on longer trips on the highway. Dirt cheap, but unreliable. Straingauges (in my experience) generally need to be tuned for every gauge which makes them somewhat more expensive.
- function_seven 9y agoOh, I think I misread my parent's comment. On my fob, it was purely to unlock the doors when you approached the car. It didn't involve itself with the ignition or running of the car. That was still an old-school key (but with the tiny improvement of a known resistor ohm-age in the key itself†) † http://ricksfreeautorepairadvice.com/gm-anti-theft-systems-overview/ http://ricksfreeautorepairadvice.com/gm-anti-theft-systems-o...
- function_seven 9y agoOne of those may have been involved somehow, but there was definitely a rattling ball in there you could hear if you shook it. I'm having trouble finding images of how it worked, but many car forums discuss the "small gold bearing in a cylinder" that's used in the fob. Unfortunately, Google wants to show me links to buy stuff. It's getting impossible to find "standalone" web pages these days.