kerrmedical.com has many different options. I got the motion detector style and love it. His feet get out of the covers and down by the floor then hits the light beam and my alarm goes off.

You can get alarm pads that work either on releasing pressure in the bed or receiving pressure on the floor alongside.

We bought a motion sensor which rang a bell when she got out of bed at night. Then the aide would get up to help her. Also you can get a necklace which detects falls and calls for help. Check amazon.

We have the baby monitor, but needed the alarm. We got a bed exit alarm that is a wireless pad under the sheet. It works great, alarming like a door bell when she sits up. I can get to her before she tries to get up.

Baby monitors! I've heard they can help.