|Manga Debut||Chapter 247|
The Sensor is a device built by Bulma.
In the purpose of collecting Nameccian Dragon Balls, Bulma built it to measure the composition of the atmosphere on planet Namekku right after the arrival. She used it to check out if there was any oxygen before leaving the spaceship. It took in the atmosphere from outside through the pipe on the side in order to break down and analyze the composition throughout the atmosphere.