Proof of concept

Bufocam is working on the raspberry pi.

Bufocam is using the archlinux image from http://www.raspberrypi.org/downloads as the debian squeeze image doesn't contain a webcam module. The nuts and bolts of motion detection are working. Setting up /etc/motion/motion.conf 

The webcam is a Microsoft Lifecam Cinema. The camera body, microphone, blue LED, IR filter and lens are removed. (Autofocus lenses contain permanent magnets!) A board camera lens holder and 2.1mm lens are fitted to the sensor.

Three 120° 100mA LEDs in series are used to light the tunnel. The polyfuses on usb ports of the RPi are rated at 100mA and are unlikely to be able to power both camera and LED array. To remedy this problem, power will be sent directly to the camera and LEDs from the 5v regulator and spliced into the USB cable.

 

Changes to the RPi image.

Image created in mac osx;
diskutil list
sudo diskutil unmountDisk /dev/disk1
dd if=diskimage.img of=/dev/disk1 bs=1m

Using Gparted; free space allocated to a fat32 partition for image storage and new partition added to fstab at /media/data

The following packages been installed using pacman;
vsftpd
motion
ffmpeg
samba

configured rc.d to run motion on boot as a daemon.

When motion is running neither the smb or ftp shares are very unresponsive. As it stands it would be impractical to download images in the field while motion daemon is operational. A download script could stop and restart motion before and after retrieving images. It might be simpler, and hence more robust, however to use a USB stick and take the images away. IP68 integrity is an issue with removable media, as is access to the hardware. (It would be difficult to remove the usb stick from within the tunnel.)

 

/etc/motion/motion.conf

the webcam supports palettes 2 (MJPEG) and 6 (YUYU)

the .pid line is commented out

saturation is set to 1

maximum resolution is 1280 x 720, currently running at 640x480

file path for image data changed to /media/data/images
allow remote users access to the web pages

     

Things to do;

Need to upgrade firmware from https://github.com/Hexxeh/rpi-update.
Try a faster SD card.
Try a USB stick for removable data storage (add to fstab to get correct path?)
Build the hardware and measure current usage.
Try a timelapse movie.