Hello, me and my friend are working on our senior project for our engineering class at school and have hit a brick wall when it comes to Arduino. We are trying to create an automatic locking door with a servo motor, controlling a deadbolt. We currently have 2 arduino uno boards, and the cheap RF transmitter/receiver set. We would like to know if we should look at an XBee as a better wireless option, and whether or not the system could be activated by being a certain distance from the door, or if a button/switch on a remote would be necessary. We also have a budget of $50 to keep in mind.