Vibrascope
The vibrascope was a type of surveillance device used by the Daleks in their city on Skaro. It was used to track vibrations. (TV: The Daleks; AUDIO: Return to Skaro)
At the onset of the Thal-Dalek battle, the Daleks used their vibrascopes to monitor the First Doctor and the Thals who were attacking the rangerscopes. When the Thals entered the city, the vibrascope registered their presence but the vibrations were too much to properly quantify. (TV: The Daleks)
Fifty cycles after the Thal-Dalek battle, a vibrascope detected Susan Foreman entering the Dalek City at Section 11. After confirming her identity, the Dalek Supreme ordered all surveillance resources to be placed on her, causing the Daleks to be caught unaware by a later party of intruders. (AUDIO: Return to Skaro)