Giant Spider #2 - Halloween 2011 The giant spider we built in 2008 turned out to be a collosal failure. The initial cam mechanism was too noisy and jammed all of the time and finally caused the threads to strip on the wiper motor shaft. I replaced this with a upside-down flying-crank style of motion using fishing line connected to each leg. This worked, but the friction of the fishing line against the head of the spider caused the fishing lines to snap one by one every night. I was exhausted running out there every day running new fishing line. What a diaster! (You can see the old spider project here) So, after we were done with Halloween 2008, we were done with the spider, too. It was dismantled and destroyed.

This year I wanted to tackle another giant spider, but this time I didn't want to animate it -- I wanted to make it to reach out and "touch" someone via a pneumatic / water spitter. This baby was quite a step up in technology for me. Not only did I integrate an Arduino microcontroller, but I also had to build a circuit to control a solenoid valve and to trigger a sound box that I made from a semi-hacked circuit.

Initial frame for giant spitting spider.	Close-up of the "undercarriage".	Who knew that pool-noodles could be so versatile?
Adding black duct-tape on the leg joints.	Duct-tape finished.	Smearing Great-Stuff (tm) spray foam on the legs. Messy stuff! DO NOT get this on your skin!
Great-Stuff foam finished. Added 3 blocks of 2" styrofoam to form the head.	After painting the legs and an initial shaping of the head.	Here's where the eyes will go, but I later swap these out for bigger eyes.
This picture gives you a sense of scale. The spider takes up 2/3 of a 2-car garage!	Here I am prototyping the circuit that I will need to use with the Arduino microcontroller to make my spider "spit".
Here is the spider with his new "fangs" attached. I carved and shaped these fangs by hand out of styrofoam.	Side-view of the head and fangs. The white tube going into the orange bucket is the water line for the spitter.	Here is the circuit I created and the Arduino Proto-Shield that I assembled. You can see the Parallax PIR motion sensor on the right.
Closer view. There is a transistor missing from the top-left corner of the board. Oops.	So what the heck is all this for? Glad you asked. When the spider sees "motion", it will trigger a sequence that includes sound effects and multiple blasts of spray mist from the spider head. There is an airline run off an air compressor that is switched on & off by a solenoid controlled by this microcontroller. The air line joins in with a water line underneath the spider head. The negative air pressure created over the water line causes water to be sucked up from the container of water and "sprayed" at the unsuspecting victim. I designed and built everything you see except for the microcontroller itself, which I programmed.
Here's the beginning of actual setup. The spider is in place but his fangs are not yet painted.	Ah, the spider looks better now that the pink fangs are now white!
Did I mention the eyes light up on the spider?	This thing is terrifying!