air bags for truck suspension
Hi Guys
New to the forum, found it through google. I'm not very knowledgeable in electronics and would love some help. I did a quick search here but no luck.
What I have is an air-bag rear suspension system in a light truck. There is an on-board air compressor and tank. There are solenoids that when triggered, add or release air from the bags and the ride height changes. Solenoids are currently manually activated with a switch.
What I'd like to do is have a very simple mechanism to monitor & adjust ride height as the load varies.
It needs to be:
a. Basic
b. Reliable
c. Withstand under truck environment (can be boxed I guess)
After lots of reading, I've settled on this idea. I'd use 2 hall effect switches (one slightly above the other) mounted to the chassis and a magnet mounted to a bracket off the axle. As the load increases and the chassis drops, the magnet activates the top hall effect switch which activates a relay which turns on the solenoid that lets more air into the bags > the chassis rises > magnet moves away from hall effect switch > relay turns off.
As the load is removed, the reverse happens. Chassis rises, magnet activates the lower hall effect switch which activates another relay which turns on the solenoid that lets more air out of the bags > the chassis drops > magnet moves away from hall effect switch > relay turns off.
However I can see a problem. As the truck is driving around, the bumps in the road (and sweeping corners) will be triggering both the switches and the relays will be constantly activating the solenoids - not good. What I think I need is a delay circuit.....something like this:
The hall effect switch is triggered & it activates a timer. If the timer reaches a pre-set time (somewhere between 5 - 20 secs, ideally adjustable initially untill I settle on a time) and the switch is still triggered, the timer activates the relay which then activates the solenoids.
There are already height control systems for air bags around but they are much too expensive and much too fancy. I want this to be a very basic & reliable "set & forget" system - no user input required.
I was thinking of using something like an
Allegro A1101-A1104 Hall-effect switch
and maybe a 555 timer with a
power on delay circuits like one of these (maybe the bottom pulse one?)
Problem is, I don't know enough about electronics to piece the circuits together or if they are even suitable. Building the board, soldering, etc is not a problem, just need some input on whether the idea & circuits will work or if there is another option I didn't think off.
Hope this is the right forum to ask this question....