How to turn on See.Sense lights?

I was given these See.Sense bike lights. I think they're a very old model (maybe first generation?). I was told they're motion activated and to give them a shake and they'll turn on.

I've only been able to turn them on a few times doing this and it doesn't seem to be consistent when I do shake them.

There's no buttons on them and when I shake them a green light comes on then, goes off a few seconds later. Does anyone know how to reliably turn them on?

Thanks!