Originally Posted By: ABV
I want to get results from real experiment.


OK cool. What are the issues holding you up at this stage? Is it the equipment needed for that experiment?


Have you considered using heavy trollies rolling/sliding on a hard surface? This would have a few of advantages:

- The low speed may mean air resistance won't matter

- You can track their motion with a conventional video camera, or even chalk marks/etc so not need the LEDs.

- You can release the spring with a mechanical hook, so eliminate all the electronics entirely.


A possibility might be using small ice cubes to support them. The ice should maintain a melted layer of water to lubricate the contact points very well.

Or do you need them to be in freefall for it to be useful??