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Issue #202 May 2007
The Wittness Camera
Build a Self-Recording Surveillance Camera
Grand Prize Atmel AVR Design Contest 2006
by Alberto Ricci Bitti
Start | Solid-State Recording | Full Interaction | Complete Picture | Basic Instinct | Filled To Capacity | Speech Preparation | Circuit Implementation | Concept To Prototype | Picture Inspection |Design Evolution | Sources & PDF
DESIGN EVOLUTION
I placed my
camera in my foyer. Your mileage can vary, but we stay there an average
of 20 min. per day, getting an impressive 120-day storage capacity with
a 1-GB card! I tested the system with 512-MB and 1-GB cards. The amount
of time it takes to fill a card makes complete coverage impossible, but
I have found that the card type is definitely important because some cards
run significantly faster. I haven’t found any appreciable performance
changes switching between FAT16 and FAT32 formatting.
Card endurance is an open issue. Although all SD cards declare some form of wear leveling, it is extremely difficult to get accurate information. Maybe you can shed some light on that subject.
The prototype works well. Now all of my friends want one for themselves. However, I know from experience that it would be presumptuous to consider this a finished product. If I get enough requests, I may make a kit that includes the PCB and hard-to-find parts. Check my web site for updates (www.riccibitti.com).
After you spend some time playing with the camera, it’s very easy to find alternative applications. For example, doors are ideal places for taking pictures. So, a relay that opens automatic doors or elevators could also trigger the camera. To fit your door, just add a reed switch or use the doorbell as a trigger.
With a spare PLC output, you could take a picture of every piece manufactured by a machine. With a photocell, you could record the license plate number and driver of every car entering a parking lot. The possibilities are endless.
I’m more than sure that you will find great new ways to use the camera’s 50,000-picture capacity. It’s enough storage to take a picture a day for an entire lifetime and longer.
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