The Panasonic KX-HCM10 camera has a small but useful I/O port that has a one bit output and a one bit input. The output is an open collector bi-polar transistor that can sink a maximum of 50mA and according to the Panasonic diagram can drive a small relay without a shunt diode! Presumably they have one fitted internally. It is operated from the external output control window that looks like this. The problem is that you need to be logged in as administrator to get there and the interface is a bit clunky requiring you to save & reload the page each time. I tested it once with a small 12 volt light bulb connected across pins 2 & 4 and it works ok. As indicated in the diagram, you could control a larger 120V operated lamp via a relay. As I have an extensive X10 system at my house, I have no real need to use it. I have however used the input to activate the alarm function which is very useful. The following sections show how you can set it up to email some pictures to you when somebody walks past the camera! I have my house & driveway camera setup like this.
As you can see from this diagram taken from the camera operating instructions, a simple mechanical contact switch can be used connected across pins 1 & 3 of the I/O port, a magnetic door switch in their example. You can use a normally open or a normally closed switch as the port can be set to alarm on either the rising or falling edge of the voltage across it. For the sensor switch, I used a simple PIR (Passive Infra Red) detector that is sensitive to body heat that I got from Smarthome. It looks like they no longer have the exact one that I do, but this is equivalent. It has connections for the normally closed switch marked N.C. that open when the sensor is activated. So pins 1 & 3 on the camera port connect to the N.C. terminals on the PIR. They can be connected any way round. If you would like a proper connector that will fit over the pin on the camera port, you can use this. The only other connection needed is for the 12 Volt power to the PIR that you can get from any small 12 volt power supply like this one from RadioShack. You will only need 100mA or less, but the 500mA is the smallest that RadioShack has for 12 Volt. No connection is required to the "Tamp" terminals. With the connections made, I just stuck the PIR onto the top of the camera with double sided sticky tape. You could of course have the PIR further away if needed.
From the camera Setup page accessed from the Config.html (e.g. http://192.168.0.160:66/Config.html) that looks like this, select the option for Image Transfer which takes you to Image Transfer page that looks like this. Next select Alarm which changes the body of the Image Transfer page to show the alarm settings. Set each item as shown below:
In section 2, check the Enable check box.
In section 3, select Always or set the operational times you want. In the Alarm enable condition drop down list, select "Rising: GND to Open (High), positive edge.". So when the normally closed switch in the PIR is activated by movement, the camera will trigger the alarm condition.
In section 4, select the image settings you require.
In section 5, set the number of images you want from both before the alarm and after the alarm. Note that you will receive an email for every picture! If you set it for 10 before and 10 after, you will get 21 emails in all for a single event. There is an extra one at the beginning to tell you the alarm has triggered (if you fill out section 7 as shown below), then one for each picture.
In section 6, Transfer Method, select Mail
Set the fields indicated here with your own SMPT mail settings given to you by your ISP and set the "To" and "Subject" fields as you require.
In section 7, if you wish to receive an email just about the alarm, fill out the fields as required. This can be useful if you want to send an email to your pager!
Last of all, click on Save!
Now that everything is setup, just walk around in front of the camera then go and check your email! Cool huh? You can also turn off the green power LED on the front of the camera from lower down on the setup page if you don't want to draw attention to it.