Help from electrical engineers.

[junk runner jr]

How does a pressure sending unit work? I am referring to a one wire unit that grounds through its base, that controls a guage. My guess is the resistance changes with varing pressure. Am I on the right track? If that is the case I should be able to use the same guage unit with a potentiometer with and arm on as my sending unit to indicate a range of movement right????. I am trying to come up with a different way to measure the hight of my air ride system since my car sits crooked with a full tank of gas and my fat ass in it. I am thinking that if I convert my guage to show a number that corresponded to a hight instead of air pressure it should work better. What do you think? Second wold be finding a Pot that cold hold up to the constant cycles of suspension travel.

[34Hupmobile]

An easy way would be to utilize a fuel sending unit and gauge. Attach the float end to the axle and the tank collar to the frame. Use a set on each side so you can level your ride.

[38Chevy454]

Junkrunner, that is my understanding how they work, variable resistance. The gauge is simply an ohm-meter with calibrated marks to indicate the poressure/level/temp or whatever.

I like the idea of using a fuel tank sender. You could get fancy and use a LVDT (not sure what exactly the acronym means), but they are electronic devices that are specifically used for measuring displacement, can be VERY accurate. A fuelk level sender is probably accurate enough for what you want.

[junk runner jr]

You got it man. That is what initaly got me thinking. I was flushing the tank out on my Goldwing and thought I can make that work... As my thought process continued I thought myself its nothing more than an Pot so could go to radio shack and get a couple. But hell a tirp to the junk yard would do just as well and I know the sending unit would hold up. I feel a Tec post coming on.

[stealthcruiser]

LVDT
linear variable differential transformer.

[junk runner jr]

what is it and how does it work?

[stealthcruiser]

as the name implies.
the ones that i am familiar with are used on jet engines,to relay a components actual position,back to the controls for that component.
they are used on the thrust reversers to show when they are deployed or stowed.
they are also used on fuel controls for said engines,but are usually RVDT's(rotary variable differential transformers),to show the position selected on the throttles to all the electronic bullshit and computers tied to them.
does that help?
a known input voltage,and a varied output voltage depending on position,best i remember.
later

[Radman]

Strain gauge.
http://zone.ni.com/devzone/conceptd.nsf/webmain/C83E9B93DE714DB08625686600704DB1?OpenDocument

[stealthcruiser]

thought of something simpler.
try doing a search on "inclinometers",and see what comes up.
you will need two.one for fore and aft stance,and one for side to side stance.they are levels with a ball inside a curved housing,liquid filled,like a spirit level.
they are used on some aircraft and other equipment when leveling them for maintenance.
oh yeah,
i am by no means an electrical engineer,
just an amateur groinicologist.
later.

[Digger_Dave]

[ QUOTE ]
I am trying to come up with a different way to measure the hight of my air ride system since my car sits crooked with a full tank of gas and my fat ass in it.

[/ QUOTE ]

Stepping outside the "box" for a second; if your mainly concerned about the "attitude" of your ride, (fore and aft and side to side) how about a "centering bubble?" (like a spirit level) That shows when the car is at the position you want. I use one on my truck with air bags. It's mounted in the ash tray. (open ash tray to check) If I remember, cost about $5.00.
(batteries not needed! http://www.jalopyjournal.com/ubbthreads/images/graemlins/wink.gif

Forgot to add; Centering Bubbles are normally used for camper trailers (or bigger ones) to get everything level when setting the corner jacks while the trailer is at rest.

[marq]

Why not use distance sensors?that way they can tell how high your ride is from the ground on either side and automatically adjust the pressure to keep the height even.Souns complicated well truth is it aint simple but there are people out there who have done it.Anyone have a wiring diagram and a shopping list of whats needed?...............marq

[junk runner jr]

great iteas guys.