Setting up suspension related inputs | AEM
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Last seen: 1 year 2 months ago
Joined: 09/03/2015 - 18:52
Setting up suspension related inputs

Hi guys

I have recently purchased an Aq1 as well as some 8" Shock sensors for a speedway car I am looking to develop the suspension set up and chassis as part of our business we would like to get this working on one of our own cars first

I am new to this type of electronics but I can navigate my way around the logger software okay and wiring side fine just not the set up of the maths needed to make the shock sensors give me the info I require I guess what I am after is some examples of the Math input for the following     I will be running 2x 8" Racepak shock sensors for a start


Shaft velocity inch/sec average for a session   and a current velocity over a set amount of samples 

Also id like to be able to set up wheel loading to specific corners of the car (will run 4 sensors eventually)

​Also any other suggestions on suspension type inputs and math examples would be great 

​I can work out whats happening allready on specific parts of the track with the shock position as to where my roll centre and where it moves in reation to specific drawings on my chassis design.

I have also noticed in the Logging Demos  that Shock FFT isnt available unless i have GDA pro  Can someone explain this to me please as to what FFT is for and why Id need it. 


Thank you :) 





Last seen: 1 day 10 hours ago
Joined: 06/06/2014 - 09:31
Sounds like we have an old

Sounds like we have an old demo file floating around out there.  FFT was removed from AEMdata long ago due to it's very limited use.  Since FFT isn't supported in AEMdata, I'll refer you to Google if you want more info on what it is.  If you're seeing the FFT views, it's because you're viewing an old template for Quick Mode.  If you turn Quick Mode off and open the AEMdata Demo project file, you'll see a better representation of current layout features.

I'm not a suspension guy so I unfortunately have no input on what woud be useful for you to see.  I can however show you how to setup the math channels to see the data you want.  Since you're effectively logging shock travel distance, if you take the derivative of distance you'll get velocity.  In Data Edit Maths, you can create a math channel and create a derivative expression.

If you scroll through that functions list you'll see that there's a lot of things you can use.  For channel data like min, max and average values you can create a Channel Report.  Go Add>Report: Channels and add in the channels you want to see and create the report.  This is an example from the AEMdataDemo project file:

I don't really know what wheel loading is but I presume it's estimated force loading of the spring based on shock displacement.  If using a linear spring, you could create a simple y=mx+b expression to calculate force.... assuming that's what you're looking for.


Last seen: 1 year 2 months ago
Joined: 09/03/2015 - 18:52


Thank you for the fast reply :) :)


I made it work using the example above allthough got some funny numbers but I think its because the example data doesnt define a unit perhaps  not sure?  The trend on the time plot vs shock position and the new channel (velocity m/s) matches the movement of the shock position so it should work from here I can see this device can be very powerful with the correct maths input :)

​Another thing im having issues with is setting up the track map with AEM VDM GPS as the inputs    I cant get it to resemble the shape of where Ive been logging that great.  Im just learning the software obviously but around 65 samples for correction seems to get it closest .  I will add that ive had it setup in my road car to get used to it and done multiple laps of the carpark and sections of road to work it out but the corners allways seem way off even when I save the track data and export the map to Google earth to check.  I have input the "distance channel setup' measurement using the speed input from gps also as I do not have any wheel speed inputs and not planning to setup.

Would next best thing be to setup a wheel speed input through math using the formula in the example(help file) for a better reading instead of gps alone?

I also have  question about beacons might sound stupid but are these the physical lap timing devices in the track?  Reason I ask is because with some of the track we willl be testing at they are just low budget tracks that often dont offer timing facilitys.  Can i make a virtual??? Beacon or marker to allow me to divide my logs into laps instead for start/finish of laps? Aswell as rally stages if i choose to use the logger or other types of motorsport?