But I am listening to audio books at the moment before sleeping :D

I have an idea for an invention. Audio-books that are linked to some sort of heartrate armband that knows how low your heartrate drops to and will automatically pause the audiobook once it reaches that level. The issue I have with audiobooks is that I will fall asleep and it just keeps going... Now I have no idea where the last words were that I recall. I suppose this could be simple-solved by just having an audiobook that pauses at the end of each chapter or every so often like every 10 minutes.