Back in 2015 I made the Pythagotron, a one-string-bass-robot which turned out to be a really nice sound mashine. Now I’m doing a polyphonic version of it. To achieve this, I had to find a more elegnat way to build a single string-unit and combine multiple ones of them into one unit.
The pitch actuator is the most intensly redesigned part of the Pythagotron: The string is positioned diagonal to the profile. I think this is a good placement, because it’t diagonal to the shape of the profile and this diretion might be better in terms of rigidity. Also, the string ist not far away from the profile but far enough to fit all the actuators in place.
Another novelty is the conversion of the rotary motion of the stepper motor to the linear motion of the string slider. Instead of the traditional approach which involves a belt and pulley, I decided to go for a linear rack gear which i can print by myself. I think this mechanic is slightly more easy on the motor. The biggest caveat with this is the size limitation dictated by the printer. Kinr has a build plate of 40×40 cm