At the weekend I installed a webcam. It is a desktop video camera (not USB and not digital). How to get the video signal from the back of the house to the server room [1]? Answer: just crawl around in the loft until you are completely black with dust, dragging two lengths of Cat 5e with you. Install a floor-mounted dual RJ45 outlet on the rafters and then plug in your patch lead from the camera mounted under the soffit. Install two sockets because you don't want to drag another cable up there ever again...
At each end install a video balun- this matches the nominal 75ohm impedance of the video signal cable to the nominal 50ohm impedance of the Cat 5e. It uses one of the four Cat 5e pairs. Use another pair to run power (12V, about 250mA)) from the server room to the camera. The camera is housed in a Click-Clack food container with a clear plastic lid. It is mounted with a ceiling camera mount ($12 from Jaycar) and contains the camera, the balun and a 7805 voltage regulator on a little board. The Click-Clack box has a rubber seal around the lid and metal clips to hold the lid down. I hope that this makes it weather-proof. The regulator has a heatsink on it that gets slightly warm. I have mounted this under the camera and I hope it will keep any condensation away. Obligatory Linux content- I use 'webcam' to capture a still from the camera every hour and upload it to my website. I plan to use 'motion' soon though as I think it is more versatile and I fancy a play. Andy -- [1] The hot-water cupboard
