I have bells that hang from the doorknob and I have trained mine to ring when she needs to go out. It works well for us. Patience and consistency- confine her to a smaller space to start and working your way up. Take her out frequently and have her ring the bells on your way out...praise with treats and pretty soon she will begin ringing on her own. Then you have to take her out immediately to her potty area and praise praise praise with yummy treats if she goes potty. It takes time but she will get it!
