Mechanisms Possible to make an automatic spring / fast moving mechanism?

In the level "Big R" https://mekoramaforum.com/media/big-r.19508/, R makes quite a dramatic entrance.

It got me wondering. I've seen the trampolines that will launch B with a manual drag, but is there any way to build a launcher that is triggered by some action by B? Is there a way to store enough kinetic energy to fling something, like B, across the level? I've seen the through-the-wall trick but I'm wondering if there's something different that can give momentum to B, R, or a ball.

 

Ha yeah I've seen that one, it's crazy. Too magical / too many steps for what I'm hoping for though. I'm thinking something more like this:



With this one however I'm unable to figure out how to lock it. Putting an automatic slider over the top doesn't seem to launch it when the slider moves off. It also doesn't add that much height to B, and that's pretty much as far as you can get away from the fulcrum