The Cosmos Stone Detector (or Cosmos Stone Locator) is a device invented by Dr.'s Ancient and Cretacia under orders by Spectre. It can, in theory, pinpoint a Cosmos Stone's exact location in time and space.
In Alien Parent Trap (episode 50), the Space Pirates captured the D-Teams' parents and made Dr.'s Ancient and Cretacia build this device to help them locate the Cosmos Stones quicker and more efficiently. Naturally, they refuse to help, but are soon forced to start work after Gavro threatens them with Torvosaurus ("You can either help us or you can help him, and all he wants is lunch.").
Because the captured scientists work as slow as they can, it takes until Desert Heat (episode 68) before a working model of the detector is ready, but this version can only show the Stones' general coordinates. As a result of this low accuracy, Spectre smashes it in anger the next episode ("You worthless piece of worthlessness!") and he makes the Ancients fix it.
A new (and larger) Cosmos Stone Detector is complete by The French Conniption (episode 71), but Dr. Ancient removes a small chip, disabling the device. Due to this, it gives multiple inaccurate locations in turn through All For One (episode 73), when Spectre first suspects sabotage.
In The Forest Fire Effect (episode 76), Gavro is shown with a hand-held version of the device, but Spectre is later shown with the regular-sized one attached to a flying pod. It is destroyed by flaming rocks from a volcano in the next episode and ordered to be repaired. But Spectre manages to take all 7 Cosmos Stones from Seth soon after, so the Detector doesn't need to be repaired at that point.