Note:
After extensive testing, I don’t really like the Seeed Human Presence sensor that much for sleep detection. Somewhat similar issues with people sitting but since there’s more movement you can set the sensitivity really low and while still avoiding getting many incorrect unoccupied readings because of people moving around a little bit while watching tv, etc.
If you want to detect sleep from beneath (through) your bed, use the DFRobot one. I trust my daily routine / alarm on the DFRobot sensor detecting if I’m in bed or not.
The Seeed one can have a hard time returning back to unoccupied (sometimes doesn’t for hours). If you set the sensitivity to lower, it can miss you sleeping entirely.
DFRobot does really well on stabilizing at a 1=occupied, 0=unoccupied (after about 15-30s to occupied, about 30-60s to unoccupied) even though it has much less configuration and “features”, it does the one thing better (you have to filter out some blips which is easy to do).