The new linear servo approach uses a flexible metal band which when bent into shape gets sturdy and still can be rolled up on a drum (cylinder)
I am using only standard parts and electronics such as the ATTiny and a DC gear-motor. (the schematics can be found in the pictures)
STL-Files will be published soon!
A motion study can be found here: https://www.youtube.com/watch?v=2p7mIsCNFCA and here: https://www.youtube.com/watch?v=T9Sq1TAgjSc