Okay, so I have pretty severe insomnia, I'll be up for days, 4 is my record so far, but recently found that my girlfriend's heartbeat puts me to sleep fairly quickly.

So she said she would be up to recording it so when I can't see her in person to listen to her actual heartbeat to fall asleep to, I can just play it. I'm looking for a (cheap) small device that can record and play her heartbeat for about 30 minutes or so, and that is strong enough for me to feel it beat slightly. I have searched and can't find much.

I have currently been up for 56 hours and counting, I am very desperate for this. I really think it would help.
So if anyone knows of any device like this, or close enough to it, please let me know as soon as possible. Thanks!!