Motion sensor

A Wattz Electronics C-U model motion sensor, or simply motion sensor is an item that detects the movement of biological material over a distance of meters using a tuned radar device. This device snaps into your Pip-Boy.

Characteristics
If placed in an active item slot, the motion sensor can be used in conjunction with the Pip-Boy 2000 AutoMap feature. The motion sensor will display all living and moving beings on the map - represented as red dots - if the "Scanner" button under the AutoMap is clicked.

In Fallout 2, carrying a motion sensor in your inventory gives you a 20% bonus to the Outdoorsman skill when traveling on the world map.

In Fallout it may be sold by Killian Darkwater in Junktown, the shopkeeper in the Cathedral or at the general store in the Hub. In Fallout 2 one can be received as a reward for Vault City quest Enter NCR and return to Stark. It is also found in the Unusual Call Box special encounter, or from the armorer in the Navarro Enclave Base, whom you must kill to obtain it.