We wanted to create a art piece called "Humans not need to count" talking about all jobs lose by robots and a the same time question if humans need to do repetitive and boring tasks as a job.
We modified some parts of the hand and forearm to be able to hold the tally counter and press it. We use a fishing line and a strong DC motor(https://www.pololu.com/product/2826) outside of the arm since force it need it is quite strong. Fishing line pass through the ring finger. We did a holder to be able to attached directly to the wall. Wrist and all fingers except of the thumb are fix position to hold nice the tally counter. The thumb was slightly modify to reach the position to click the tally counter that is quite close to palm of the hand.
You can see a demo video here: https://youtu.be/cnDQ1G789YM
Arduino code it is published here: https://github.com/var-mar/HumansNeedNotCount