15 kills with a silencer
Primary weapons (except SMGs) can unlock the heartbeat sensor attachment. First you must unlock the silencer attachment by getting 75 kills with your chosen gun. Then you must get a certain amount of kills using the silencer on your chosen gun (I believe the number is 20) and then you will unlock the heartbeat sensor for use.
You can have both attachments on if you unlock the gun perk that lets you have two. ie, kick, focus, attachments
Yes.
15 kills with the silencer =]
ther are no controlls
Heartbeat Sensor is not a Gun, it's a Attachment for all Assult Rifles. It is unlocked by killing 15 people with the silencer.
You can't get a heartbeat sensor on a secondary weapon in the game. The only possible way is to do some sort of hack on it, which is probably not the best thing to do.
itdepends on the map but i think heartbeat sensor is awesome but some people get ninja perk so they cant be seen by it
Ninja Normal - Nonseen On Heartbeat Sensor Ninja Pro - Nonseen on Heartbeat Sensor + Dead Silence (can hardly hear your feet when u walk or run)
just get kills with the gun, then when you unlock attatchment like the red dot sight, getting kills with that attachment on will unlock further thing like so: grenade launcher - underslung shotgun silencer - heartbeat sensor red dot sight - holographic sight FMJ - extended mags ACOG scope - thermal scope
Heartbeat is definitely the way to go. First, UAV only lasts for a little while, 30 seconds I think; although it works all across the map. However, heartbeat sensor is always working. And although it has a smaller range, it never runs out.