The Spacepod Cam
The purpose of the spacepod cam was to send live photos
from the road to the internet during our journey to r2k.
The spacepod cam also ran during the car show itself.
An archive of spacepod cam photos will eventually be
available here.
The hardware
- 3 USB Connectix Quickcam LC's
- 7 port usb hub
- DC adapter for hub
- 2 iBooks with Airport cards
- 2 DC inverters for iBooks
- Alien yard gnome
- Various hardware for mounting cams
- Motorola Startac dual band wireless phone w/ data cable & car power adapter
- Keyspan USB adapter for Palm (connected Startac data cable to USB port on iBook)
- Three socket DC "power strip"
- USB extension cable (to help budvase cam reach the hub in the back seat)
The software
- Sitecam web cam software
- iDo script scheduler
- Anarchie (FTP) v3.6.2
How it all worked
Two cams were mounted in the alien garden gnome and looked out the rear
window. The third cam was mounted in the front bud vase and looked
either out the front or back into the car.
The three cams were driven by Christa's blueberry iBook ("Excellent")
which rode in the back seat. They were connected to Excellent via the
USB hub which was powered from one socket on the 3-socket DC "power strip"
(our two wireless phones occupied the other 2 sockets.... no
high-powered items, such as the iBooks, could be used with the 3-socked
adapter). The iBook was powered via a DC inverter plugged directly into
the rear power outlet.
Excellent was running Sitecam (this actually takes the photos at
scheduled intervals) and iDo script scheduler. Sitecam was scheduled to
take photos once every five minutes from all three cams in rapid
succession. The photos were numbered sequentially and stored in
folders on Excellent.
lisa's tangerine iBook ("Squishy") was set up as an Airport Software
Base Station. This meant that Squishy's hard drive could be shared to
Excellent over Appletalk. Every 30 minutes, the iDo Script Scheduler
would run a simple AppleScript (recorded with the Script Editor) which
copied 30 minutes' worth of cam photos from Excellent to Squishy.
The StarTac (phone) was connected to Squishy using its data cable and
the Keyspan USB adapter plugged into the USB port (see Resources below
for specifics). Although I had an Applescript which would ftp the
photos up to my server (including dialing in and disconnecting), I
decided that the script was not robust enough; if the connection failed,
it did not recover well (or at all) and with my primitive Applescript skills
I was not able to program around this problem. So I manually connected
and ftp'd the files every 30 minutes.
I also did periodic manual adjustments to the cam software to improve
picture quality, but by the end of the trip we'd mostly stopped doing
this. It probably wasn't entirely necessary; Sitecam will automatically
attempt to compensate for changing light conditions.
On the web server I had a Perl script which ran every 5 minutes to copy
the most recently taken photo to the file which actually displayed on
our web page. Visitors to the web site would actually see what was
happening 30 minutes in the past. This script also created an archive of
all the photos, numbered sequentially.
We had a terrific suggestion from Big Al while we were on the road; he
asked us to display our current location in the cam photo. So I
created a little green index card with the name of the closest city and
the little bendy alien sitting on our dash served as a convenient holder
for these cards. Low tech and very effective :)
References
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