(In the words of the White Stripes)

So I'm thinking, doorbells are dumb old device, its a button and a bell...

So in the same vein as my Pocket PC Caller ID application, I'm looking at building a new doorbell powered by something embedded and CE or . Net MicroFramework.  

So lets look at the basics;  what could throwing a load of tech at the humble doorbell possibly add.   This is my list -

• Ability to take photo of the person at the front door - mmmm Windows CE webcam project see (http://msdn2.microsoft.com/en-us/library/aa459161.aspx)
• Sending remotely via email/IM who's at the door - useful for home security.
• Not waking up the children - a popup alert on each home PC rather than an intrusive ring.
• Get rid of that boring ding-dong,  lets play a user defined wav file
• It would be sooo cool.

So I've started the ball rolling,  I've built a test harness program that does the email notification, the sound and the reading of the serial port pins, that will be used for the front door bell switch.

The eventual solution, will I be a headless device (i.e a device with no screen), connected via a serial cable to the door switch.     The headless device will be inside the bell box linked to my home network either wirelessly or with a network cable.  I know you can get X10 doorbell switches,  but I'm trying to do this as contained as possible.

The .Net Compact Framework 2.0  has a great event System.IO.Ports.SerialPinChanged

This should allow me to detect a simple pushbutton press, by using (and I haven't thought all this through yet) say the CTSHolding lines on the serial port.

See http://www.aggsoft.com/rs232-pinout-cable/pinout-and-signal.htm

We can monitor the property  serialPort1.CtsHolding  to let us know if the door switch has been pressed or not.

So, cool project, early days.   I'll race you!   You try and I'll try and we'll see what we come up with.   

Again let me know if you want the source so far.   Happy to share.