Sonar-type sensors were first developed at what time?

The development of sonar-type sensors can be traced back to before World War I, particularly with the advent of underwater sound detection technologies. In the early 1900s, significant advancements were made in acoustics and the study of sound transmission in water. The basic principles behind sonar, including the detection of submarines through sound waves, were explored during this period. This foundational work laid the groundwork for more advanced sonar technology that would later be utilized extensively during World War I and beyond.

Other timeframes mentioned, such as during World War II, or the 1950s, focus on developments and enhancements of sonar technology rather than its inception. While sonar saw significant improvements and widespread deployment during these later periods, the original concepts and preliminary technologies were established earlier, prior to the global conflicts that followed.