Hey all! It's been forever since I last posted.

Programmable Springs are compliant series elastic actuators proposed by Bill Bigge & company.
They are touted as "a better hobby servo".
I've directly contacted Mr Bigge for 3 years running.
He has reasons for "delaying work" on the Programmable Spring for the moment.

Does anyone here know of someone that has built a programmable spring servo based on the publications and website description by Bigge & associates?

I've scoured the internet to no avail. There were some nice videos.

A positive response is not expected, but this query is a desperate attempt to leave no stone unturned.

Programmable Springs seems like a good idea that may be fun to implement on walking bots.
Is there any evidence to the contrary?

Maybe he's delaying since it's not that great a deal after all.

Thanks for your time.