  Soft-robot designs are manifold, but only a few are publicly available.
Often, these are only briefly described in their publications. This complicates
reproduction, and hinders the reproducibility and comparability of research
results. If the designs were uniform and open source, validating researched
methods on real benchmark systems would be possible. To address this, we
present two variants of a soft pneumatic robot with antagonistic bellows as
open source. Starting from a semi-modular design with multiple cables and tubes
routed through the robot body, the transition to a fully modular robot with
integrated microvalves and serial communication is highlighted. Modularity in
terms of stackability, actuation, and communication is achieved, which is the
crucial requirement for building soft robots with many degrees of freedom and
high dexterity for real-world tasks. Both systems are compared regarding their
respective advantages and disadvantages. The robots' functionality is
demonstrated in experiments on airtightness, gravitational influence, position
control with mean tracking errors of <3 deg, and long-term operation of cast
and printed bellows. All soft- and hardware files required for reproduction are
provided.
