Poor Man's Ride Height Sensors -- need to source a part

[Jack Olsen]

I need two rotary-style potentiometers to use as components in some one-day-and-throw-away ride height sensors. These things are under a buck at Radio Shack, but they all seem to have a full 360 degrees of range on them, which will make them less accurate for the limited movement my suspension will generate.

I've been told that the same type of items are made with 45-degree ranges (or 30 degrees, anything in that neighborhood). In other words, the full voltage spread they put out will be localized to a pie-shaped section of a circle instead of a full 360 degrees of rotation.

I need to find some of these. The plan is to feed them into my data logger on a controlled set of flat highway at a set speed and have the software for the data logger filter out actual ride height changes from different wings, spoilers and such.

Anyone know of a source for this kind of thing? They don't need to be weatherproof, or survive massive duty cycles. Like I said, I plan on using them and then taking them off once I've got data on a handful of aero configurations for my 911.

[ZOA NOM]

Jack, try "Precision Linear Motion" pot. Look here . They might be easier to adapt to your wing setup. There are also some "string pots" that are spring loaded and unwind to provide voltage change.

[chrisp]

Is your suspension that supple that you will get reliable measurements that are a result of downforce and not the bumps in the road? You can filter out the bumps as spike loads but the stiction in the suspension will skew the readings.

Why not strain gauge the base of the wing or wing support?