Motion detector floodlight We used a Cooper Regent
Floodlight bulbs ( 2) $3 each
2-conductor cord with power plug about $5
Wood board, 12"× 18"
Wood dowels, 1" diameter, 9" long ( 4)
Wood screws ( 4)
Empty tin can with ends removed
Computer We used a Mac laptop.
Webcam if the computer doesn’t have one built in
Motion detection software We used BTV Pro
( bensoftware.com, $34, free 15-day trial). Other
similar programs exist for both Mac and PC.
Cyanoacrylate glue aka super or crazy glue
Bait such as pet food or old fruit
PVC pipe (optional)
Power drill and drill bits
NOTE: I really don’t know what I'm doing playing
with wires and electricity. Please take care to
protect yourself appropriately.
The lights and motion sensor are designed to
work outside, but rain dripping into the sockets can
be a hazard. So we mounted the device under a protective platform built by simply screwing 4 wooden
dowels into the corners of a board. We attached
the motion sensor light underneath, following the
included instructions. We also bought some PVC
pipe to fit around the legs, to use as stilts if we ever
want to raise the platform.
Motion sensors detect movement over a wide
angle, so we duct-taped an empty tin can with both
ends removed over the sensor (see Figure A). This
serves as a blinder so that only animals right at the
bait will make the light turn on.
To capture video from inside the house, we used
a Mac laptop and a webcam running BTV Pro. This
Mac-only software has a motion detection setting,
plus a nice option to show the time in the corner of
the video image (Figure B).
For bait, we’ve successfully used inexpensive
cat food, old fruit, or scraps from dinner. Before we
retire for the night, we just start up BTV Pro and
158 Make: Volume 17
Infrared motion detector
Tin can with both
Fig. A: The setup is very simple. Fig. B: Closeup of
a nighttime visitor. Fig. C: Backgrounds added for
put out the bait. Then it’s like the old Easy-Off oven
cleaner ads: it works while you sleep!
After our first night’s success, I thought we might
just keep getting the same cat. But the diversity of
animals we’ve captured on video has been amazing.
In our first month, we shot 9 species: raccoons,
cats, 1 robin, 1 wren, 1 catbird, 1 sparrow, 1 squirrel,
1 rabbit, and 1 human — our neighbor’s son passing
through our yard early one morning. And we’ve had
possums come so regularly that we started putting
out decorative backdrops for a laugh (Figure C).
The entertainment payback for this easy and
inexpensive project has been terrific. Setup takes just
a few minutes each day, and an animal appears most
nights. Some animals have given us quite a laugh, like
a possum that walks slowly in reverse each time the
light turns on, a young rabbit that appears to panic
and run toward — instead of away from — the house,
and a squirrel who’s learned to evade the motion
sensor with a commando-style crawl.
Illustrations by Alison Kendall
Bob Goldstein is a dad who enjoys making stuff. His son
wants to be an inventor when he grows up. Their videos
can be seen at animaldetector.blogspot.com.