pet communicator using old smart phone to control arduino.

I want to create a web enabled pet communicator using and old phone to control the arduino servos to dispense treats and also 2 way communication. this is maybe way over my head but i think could be a great way to re-use an old phone.
I think I could run a web cam app and control servos via text message. any ideas will be appreciated.

happy Halloween ]:smiley: