Sunday, November 1, 2009

Halloween Dropping Spider

My Halloween project consisted of a dropping spider triggered by a PIR motion sensor mounted on a Jackolantern. The motion sensor triggered a dropping spider, lights, sounds, low laying fog and finally a tweet with a picture attached (

These are the parts that I used for this project:

It's all pretty basic. The arduino controlled the PIR motion sensor, the servos for dropping spider reel, Jackolantern LED lights, toy with scary sound, and the X10 CM17A. Then the arduino sent a serial message to the ioBridge serial API telling to GET the URL of my site. Then on my site I had a bash script with a while loop looking for request coming from the ioBridge server, then the script played a sound, grab the picture from a wireless webcam and post it to twitter via twitpic's API using cURL.

Arduino Sketch
Here is the arduino sketch. I used the X10Firecracker and the Servo libraries as well as the PIR sensor example from the arduino playground.

Spider Reel
I end up using an VHS tape as a reel. I had to modify one servo to have continuous rotation. I used this guide to do so. The second servo just did the lift part.

ioBridge Monitor
To establish the arduino-ioBridge serial communication I was planning to use an RF solution, but due to time constraints I had to use a long speaker cable to connect the arduino TX to ioBridge's Serial Board RX with one wire and the second for GND.

This is the bash script I used to trigger a sound as well as send a twitpic.

I used my mac os x Apache 2 server. I had to give write permisions to the access_log so I could append a bogus line as a "break".

while true;do
status=`tail -n 1 /private/var/log/apache2/access_log | cut -f 1 -d "-"`
if [ "$status" = " " ]
echo "Boo" >> /private/var/log/apache2/access_log
afplay /full/path/Halloween/werewolf.mp3
msg="Boo, victim $booCounter just got really scared"
sleep 5
curl -O
curl -F media=@/full/path/Halloween/IMAGE.JPG -F "username=username" -F "password=password" -F "message=$msg"
let booCounter=booCounter+1

Fog Machine 
I got this fog machine that comes with manual fog release switch.
 I just soldered the 125VAC/10A DPDT Plug-In Relay to the switch and connected to an X10 appliance module.

Fog Chiller
I made this low laying fog cooler following this instructable.


I originally used a PING sensor but got better results using the PIR sensor instead. I had to decrease the sensing radius by creating a cone (pumpkin nose) around the sensor.
The twitpic implementation could have been better. Camera placement and lighting were poor :(


  1. WOW!! Esta genial!!!

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