RFID, door button project

Dear All Expert,

I wish to ask opinion about my project. I wish to do a DIY home security system. I had a center controller using Arduino Mega connected to a Zigbee. I had a few motion detecters around the house to sense motion and sense message to the center controller if motion is detected.

At the exit of the house, I would like to have a RFID reader and a few pushbutton connected to Arduino board and a Zigbee also. The purpose of the pushbutton is to arm or disarm the house when the owner is leaving or entering the house. The RFID is used to authenticate the home owner when disarming the security. I would like to add a few more buttons so that I can add other feature in future.

I would like to know the design option for the door switch. What arduino should I use? Can it be run using batteries? How long will it last with batteries? I am thinking of using Parallax RFID reader model #28140. What is the minimum connection needed for the arduino? The Zigbee is used to send message to the center controller when pushbutton is pressed to allow the center controller to know when the system is armed or disarmed and do the necessary action when motion is detected.

Hope that all can advise accordingly. Thanks a lot

I would like to know the design option for the door switch.

You want to make your own switch? I'd buy one. It's far easier.

What arduino should I use?

Any of them that say Made In Italy.

Can it be run using batteries?

Yes.

How long will it last with batteries?

Long beyond the time that the batteries go dead.

I am thinking of using Parallax RFID reader model #28140.

OK.

What is the minimum connection needed for the arduino?

I don't know. I don't look things up for people. I expect you to do that, and post a link.