Self-Locking Device Recommendations for Add-A-Motor Auto Coop Door

[nincomcoop]

I'm planning on installing this auto coop door http://www.discounthomeautomation.com/Add-A-Motor-Chicken-Coop-Motor-AAD20 and am looking for recommendations on a self-locking feature to ensure raccoons can't slide the door open. Any/all ideas welcome.

Thanks.

 

[Dogfish]

This set-up works well for me. Same motor. The key is to attach the weight off center, to the side you want it to fall.

http://s137.photobucket.com/albums/q233/mesoas/Chickens/?action=view&current=0401000714.mp4