Silly String Shooter

Ok so after over a year of messing about I finally have completed my Silly String Shooter. It serves no higher purpose other than to optically recognize a threat and neutralize it with gooey silly string.

Here we have it with the heavy duty missile switch to arm the device, a potentiometer dial to adjust for range and an arcade over ride button to commence firing at will.

To begin I started with some basic hardware and an arduino. A friend, Andy suggested using a hinge to depress the button on the spray can. I also had some scrap wood, some "L" brackets.

After I roughed in a vertical post I mounted the servo and hinge. I cut and bent a wire coat hanger for the armature to operate the hinge. This worked marvelously.
I then proceeded to wire up an IR sensor and mount it to one side of the post (so as to "see" around the can of projectile goo).
I found what I thought was a reasonably sized enclosure for the arduino and such and proceeded to stuff it to the gills with buttons, dials, batteries and switches. Here is a shot of what is contained in the enclosure. Basically a battery, arduino, a dev shield, and the aforementioned external controls.
With a little bit of code I can use the powered up arduino to react to 2 different stimuli. The arcade button when depressed sends the servo into a pulsing fire mode that squirts unsuspecting intruders or kittens with silly string. Alternatively by arming the device and setting the distance with the potentiometer knob, perpetrators that break the IR beam are squirted automatically.

Check out the video for a crude demonstration.