Multi-function device of Ancient origin, capable of detecting human and Wraith life signs, radiation and power sources, and more. The device is portable and hand-held, easily concealed in a vest pocket, with a detection range of approximately 100 meters. Puddle Jumpers come standard with at least one of them.
The Wraith are aware of the technology as having belonged to the Ancients -- the Keeper recognized it on sight. Individuals detected by the device appear as blinking squares on the display. While its Ancient name is unknown, Lieutenant Aiden Ford was eager to name it a "life signs detector" when it was first discovered -- though it has other functions.
The Lantean medical scanner is a slightly different version of this technology.
Rising, Part 2 - Sheppard accidentally discovers the life signs detector technology in the wall of his Puddle Jumper when wondering how he will find his teammates.
Childhood's End - When his Ancient scanner loses power on M7G-677, McKay uses a compass to locate an electromagnetic field generator.
Underground - McKay's scanner detects an underground power source on the Genii homeworld, leading him and Sheppard to a shocking discovery about their new allies. When they infiltrate a Wraith hive ship, McKay uses the device to break into a room and steal a computer interface device.
The Tower - Otho uses an Ancient scanner on Sheppard's team and soon discovers that Sheppard's Ancient gene is stronger than any member of the royal family in hundreds of years.
Vengeance - McKay uses his scanner to track Michael's genetically engineered creatures through a maze of underground tunnels.