The Witness Camera is an automated, self-recording surveillance camera, that uses a gigabyte-class flash card as recording media.
the system from a VGA CMOS colour camera, a passive-infrared (PIR) movement sensor, an ATmega32 processor, and a 1GB SD-card.
The prototype looks like an ordinary alarm detector. But when it detects people moving around, it silently starts recording.
A 1 GB card can store 50,000 colour frames, with a definition similar to industrial VHS-CCTV recorders (320x200), taking a new picture every 2.5 or 3 seconds. On most typical domestic environments, this translates to more than one month of images before overwriting the oldest frames.
The Witness Camera features also a high resolution mode, taking pictures at 640x480 pixels every 3.5 or 4 seconds. Thanks to embedded image compression, the same card can contain as much as 25,000 frames when high-resolution is selected.
The recording system is flexible, allowing to choose between PIR activated, timer, continuous and externally triggered recording modes. You can decide what intervals to use and how many extra frames to take after a trigger ends.
Creating new applications, like an automatic door capable of taking snapshots of persons entering a building, or using it as an in-vehicle recorder, is simply a matter of selecting the operating mode and connecting a trigger source.
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