Can 3D printed objects (plastic or otherwise) without batteries and electronics be connected to the internet?
Apparently so although that may depend on what you define as electronics.
The approach uses ambient wifi to absorb or reflect signals and communicate in a binary (on/off) manner.
With this method buttons, knobs and sliders can 'talk' to each other and other devices via wireless connection.
So basically, anything that can move or rotate can relay it's current state.
Obviously power is present somewhere in loop of the greater system (via smartphone, router etc.) but no power is required in the sensor itself thus suggesting almost any object can become a sensor using the ambient signals already present in the air. Those signals can then be absorbed or reflected to communicate their current state.
Video Link: https://www.youtube....h?v=gU6-o9SIkMQ