I had this crazy idea - Lets build a shock dyno with Linuxcnc

Thanks guys. Its very encouraging to have some feedback and interest in this crazy project. Andy, I did have a quick look at the back cover today. Its held on by 4 screws. I've been pretty reluctant to take the motor out of the crate it came in because its bolted down and is forkliftable as it is. I weighed it on my vehicle scales as it came in and it was 124kg so its not easy to mover
around. But then I remembered I have a small but solid trolley on wheels that has a 60mm plywood top on it. So I think when I get a chance, I'll bolt the motor down on that and it will still be mobile. That way I can work on it and push it out of the road when I'm not. Who knows the trolley might become part of the build.

Andy, thanks. I have not had any spare time to work on the CAD files. I might have a window now for a week or so as I wait for others to complete some tasks on some work related projects. I'm paying the bills so it has to come first!

I'm going to jump in here, hopefully it's not unwelcome.

I've been dreaming of a dyno build for years but never seem to get around to it. Getting things like a vertical mill up and running seemed more pressing. But now it feels like time. I've been accumulating parts for a while now.... Rodw's use of a linear bearing for the scotch yoke blew my mind, I had much more complex ideas, but that seems like such a workable and easy solution.

My first step is go build a spring dyno, then a shock dyno, on the same control system to save on cost. The spring dyno will just be some solenoid valves, pneumatic cylinder, load cell, and a glass scale linear encoder.

The real value is in gathering the data at a reasonable rate and smuggling it out of the linuxcnc environment into something useful like a database. I guess it's up to me to pickup from halstreamer and do something useful with the data....

Anyone have any suggestions about this approach? Thoughts on the electronics? Should I look elsewhere? I've got a reasonable knowledge of linuxcnc and HAL and it seems like leveraging HAL would be the most sensible thing over finding some other software or writing a dedicated system for raspberry pi or maybe a teensyduino 4.x.

It looks like I'll want:
2+ quadrature encoder inputs
A few reasonable resolution analog inputs
+/- 10v output for servo drives to the dyno preferred, but could probably live with step/dir
Some digital outs for the solenoids
Running an external card (not pci/pci-e) would be preferred.

It seems like maybe a 7i97 would be a good place to start if a bit overkill?

Rodw, Have you gone a different way with your dyno project? Or is it just a bit stalled in 2020?

andypugh wrote:

I had forgotten about this discussion.

I had too but the last few days its been back on my mind... Thanks to dberndt for finding this thread again for me!

Too many projects competing for my available budget for time and cash but I have a shipment of shocks arriving in early January! I'm out of time on Christmas morning but I'll come back on Boxing Day!