To me, interaction is an entertaining communication between two actants, with either or none of them human, but doing man-like actions. Also, it’s consuming people’s senses like sight, hearing and so on.
In this sense, I think the sound circuit art designed by Peter Vogel can be considered interactive. First of all, it’s a communication between people and the machine: the music will be played if people put their hands above the machine. Also, it is entertaining, for people can change the sound by changing their hands’ position, and that provides a sense of freshness to the participants. Last but not least, this project is sense-consuming. It engages sight and listening. 
However, what I’m really curious about is that it seems like many interaction projects are a lot like search engines to me, and therefore is quite different from my definition of interaction.
For example, the project “sleep like mountains” by Lotta Stöver. It functions in the way that the computer scans the body and then provides data sets by comparing the body to mountains. This is very much like what a search engine would do instead of “Interaction”. However, it does shows a certain connection between computer and human, just that this kind of connection doesn’t really mean “interaction” to me.
Citation:
Eric Forman. (2015, September 12). Peter Vogel Sound Circuit Art. helloCircuits! Retrieved February 22, 2022, from https://hellocircuits.com/2013/10/19/peter-vogel-sound-circuit-art/
Visnjic, F. (2022, February 8). Sleep like mountains – (re-)discovering bodies in landscapes. CreativeApplications.Net. Retrieved February 16, 2022, from https://www.creativeapplications.net/processing/sleep-like-mountains-re-discovering-bodies-in-landscapes/