Heartbeat Sensor



The Heartbeat Sensor is an attachment used in Call of Duty: Modern Warfare 2. The attachment allows the user to track multiple targets, somewhat like UAV and very similarly to the motion tracker in Halo 3. It displays the positions of people who are fairly close to and in front of the player. The display screen can be folded out from the side of the weapon and folded back in again. The first time it is used is in the level Cliffhanger, where Roach finds himself in near white-out conditions. The sensor uses some kind of IFF system to tell the difference between friendlies and enemies. Friendlies are blue dots and enemies are white. In multiplayer, friendlies appear as green dots instead of blue and enemies appear as red dots instead of white.



The new version of UAV jammer, Cold-Blooded, cannot block the sensor; only the perk Ninja can. This attachment is compatible with assault rifles, light machine guns, and sniper rifles. To unlock the Heartbeat Sensor, one must get a certain amount of kills with a suppressor attached to the weapon they want the sensor for once they have unlocked the suppressor for that weapon.

It will not detect enemies (or friendlies) that have already been killed, due to the fact they have no heartbeat.

Advantages

 * The Heartbeat Sensor allows the user to know where enemies are without the use of a UAV, making it valuable for certain stealth classes and setting up ambushes.
 * In Hardcore, where the minimap is mostly disabled, the Heartbeat sensor will allow you to still find enemies before they see you.
 * It is especially effective for the sniper rifles as it allows the sniper to be alerted to the danger of an approaching enemy (unless said enemy is equipped with the Ninja perk).
 * The Heartbeat Sensor allows the user to see enemies through any obstructions, such as walls and smoke screens.

Disadvantages

 * There is a somewhat long period of time (slightly longer than a UAV) between periods when enemies show up on the sensor
 * The sensor cannot be seen while using ADS (save for a small portion of the top of the screen) or while sprinting, however, a beeping sound will still alert the player if enemies are close by. However, some weapons (most notable the FN FAL) are near perfect with the sensor allowing you to still watch the sensor and aim down the sights.
 * Turning tends to cause a motion blur on the sensor's screen, making it somewhat imprecise while on the move.

Trivia

 * The item is a reference to Tom Clancy's "Rainbow Six" book in which a counter-terrorist group makes use of heartbeat sensors, which were created in the story.
 * The Heartbeat Sensor cannot be folded back towards the gun in multiplayer.
 * The Heartbeat Sensor seems to have a smaller area of effect in multiplayer. This was done for balance purposes.
 * The player will get a fuzzy screen when the enemy team uses an EMP. Therefore the player cannot see anyone on the Heartbeat screen until all electronics are restored.
 * There is a known glitch where if a player is using the Ninja perk is killed by a player using a Heartbeat Sensor, the former player will show up on the killer's Heartbeat Sensor when watching the KillCam.
 * This might be a reference to the "Alien" movies; the soldiers in that movie had "motion sensors" attached to their weapons.
 * This also might be a reference to the "Stargate Atlantis" series, where they have "Lifesigns Detectors" showing forms of life around them.
 * In campaign, a AA-12 with a heartbeat sensor can be used. The heartbeat sensor is not available in multiplayer.
 * Heartbeat sensor is very hard to use on splitscreen mode since the screen is smaller.