That's its control system. What's interesting is that all of its actuators are soft. You can imagine that a set of simple soft components like that simple oscillator, combined with some small rigid components containing a microcontroller, would belike a full soft robot.
In the broadest definition, a sensor is an object whose purpose is to detect events or changes in its environment, and then provide a corresponding output. [1]
If we follow the above definition given on the Wikipedia then some important and interesting issues arise:
Is sensor not a device that behaves in certain manner to some energy stimulus and thus allows us to connect outer energy to the autonomous system (robot) being developed?
Should a sensor always transduce to electronic energy form?
e.g. a gear lever in a bike is not a sensor? it senses (may be pressure) and thus allows the system (the bike) to sense some outside stimulus.
Please feel free to define sensor in a different manner if you disagree with [1].
