Usage

This mod adds the Heartbeat Sensor weapon attachment from Call of Duty: Modern Warfare 2 (2009) as a weapon gadget in PAYDAY 2. It functions in much the same way that the original did- see the video for a demonstration:
<div class"spoiler">

Spoiler!

Know what kind of heat's just around the corner.

Never again be caught flat-footed in a fight.

VR Footage, shared by VxWolf:
https://i.imgur.com/UmVBfgB.gifv

Stats:
* -1 Concealment
* -3 Stability

The Heartbeat Sensor sweeps the surrounding 25-meter radius area for heartbeats and displays their locations on the readout screen.
Friendly IFF signals are denoted in blue; neutral/unregistered or potentially hostile signals will appear in white. (This includes civilians, so watch your fire!)

Applicable Weapons

This attachment is generally only available for primary-slot Assault Rifles, Sniper Rifles, or Shotguns. (As a notable exception, the Piglet is also included, because why not?)
The reason that this gadget is not universally available is that I have to manually set the position of the HBS gadget for each weapon. If I didn't, the gadget would likely be somewhere on the gun that is not visible to the user, rendering it useless.

This mod works on the following PAYDAY 2 weapons:

This mod work on the following PAYDAY 2 user-created add-on weapons:

Remington ACR https://modworkshop.net/mod/19917
FN MK 17 MOD 0 https://modworkshop.net/mod/26539

Please note that you can only apply the Heartbeat Sensor attachment to these weapons when they have a left-side optics mount/rail. Certain attachments may be incompatible- make sure that the game does not tell you that you have incompatible attachments for these weapons.

Credits:

The concept and execution of this weapon attachment originated in Activision/Treyarch's game Call of Duty: Modern Warfare 2 (2009).
The model used in this mod was uploaded by Asagrid.
The model and materials were ported to a Diesel-friendly format by Alcat101.
The scripted functionality, sensor readout screen bitmaps, in-game descriptions, and mod page images were created by Offyerrocker.

Support and Known Issues

Here is a list of known issues with this mod:

Heist environment bloom settings affect the screen. This means that the screen may be unreadably bright on certain heists, such as Yacht Heist, or merely very difficult to read, such as on Heat Street.
Light sources and certain objects may render through the screen.
Detected heartbeats "blips" may rarely linger for a few seconds longer than they should (cause unknown)
SWAT Turrets will not show up on the Heartbeat Sensor readout, owing to the fact that they do not possess heartbeats. This is intentional.
Zombie faction enemies (as may be encountered on Cursed Kill Room) still show up on the Heartbeat Sensor readout, even though they don't have heartbeats. This is not intentional.