HDMI switcher

Hi all! I would like some feedback on the feasibility of this idea. I am planning on installing security cameras in my house. The bedroom has a large flat screen TV. The front door will have a camera and ultra-sonic sensor (to know when someone is at the door). My plan is to feed an arduino the ultra sonic sensor signal. I will also convert a (cheap) HDMI switcher. The button that toggles from HDMI to HDMI on the switcher will be eliminated, replaced with a small mosfet transistor switch. My hope is to have the HDMI switcher change to my security camera DVR channel and show any video activity on the bedroom TV. It can even trigger a low volume sound alerting of activity. Yes? No? Maybe so?

Have you looked at any switches yet? Link the ones you have and you might get a reply on how to go about it as hacking them would not be uniform.

Look into an IR solution as an option. Set it up so the Arduino sends IR commands to change inputs on the TV instead of buying/hacking a switch.
The only bookmark I have of this nature, Control your LEDs with your TV remote?! || Arduino IR Tutorial, will show you how to capture the correct IR signal.