Biology Electronics Aesthetics Mechanics
This is a BEAM solar power smart head with 2 degrees of freedom. The motors came from an old video camera, the rest of the parts from various techno-scrap. I got lucky with the gear motors, which have mounting brackets that allowed me to attach them to each other without fuss. The face plate is attached to the Y-axis motor with an alligator clip. The light sensor uses 4 photoresistors arranged in a diamond formation to track light on two axes. It is sensitive enough to track the "flurry" screensaver on a computer monitor when the lights are out. All of the circuitry is mounted on the back of the face plate. You can see the bot struggle to lift its head because of the extra weight.
Here is another movie of the head tracking a flashlight.
A BEAM power smart head seeks the brightest light source in the room by pivoting on one or more axes. This BEAM head has only 1DOF, but heads with 2DOF are out there. Maybe some day (That day has come -- see above).
In this movie the head tracks a moving object. At equilibrium, the head sits quietly and trickle charges its storage capacitors from an overhead lamp. The mechanical parts come from a discarded CD player. Two 1F capacitors store the charge. The circuit is Wilf Rigter's SPSH v2, a bicore oscillator in which the duty cycle is altered by light falling on the photodiode "eyes" on either side of the solar cell. The translation from breadboard to an actual bot was rough going, so I'm pleased it works as well as it does. Those hoods over the photodiodes are not attractive, but they keep the head from becoming too nervous when a bright light is nearby.
Pummers are fun to build because weight and mechanics are of no concern. One is free to concentrate on appearance. These pummers use crumb catchers and strainers for the bases and flowers. The flower of the smaller pummer is a pipe cap I found in my garage. The stems are fashioned from random hardware I picked up at the Scrap Exchange in Durham.
The electronics consist of a suspended bicore circuit based on the 74AC240 inverter powered by solar cells charging a 1F storage capacitor. It was a bit of trick scrunching all the components under the crumb catchers. The high-intensity blue LED in the small pummer illuminates an entire room! Click the image for a movie.
This is a typical photopopper: small and vaguely insect-like.
I took pains to hide the circuitry this time, giving the bug a cleaner appearance. The body is a large storage capacitor and the eyes are two photodiodes on either side of the capacitor. Two pager motors held by fuse clips serve as legs. The clips are soldered to a bent paperclip, which serves as a frame. Solar cells serve as wings (yes, this is a stretch).
This popper is lightweight and lively. The pager motors deliver surprisingly large pops, aided by an efficient solar engine designed by Wilf Rigter (MillerPopper v.7). It really moves in bright sunlight. Click the image for a movie.
This is my first photopopper, a small, solar-powered junkbot that seeks out the brightest light source.
The motors are harvested from two old cassette decks. A 4700 mF storage capacitor under the solar cells serves as a body for this robot. Two photodiodes sticking up on either side of the motors serve as eyes which respond to light. If the right eye is in a stronger light, the left motor fires, and vice versa. The solar cells recharge the storage capacitor until a motor fires again.
Yes, this robot is unsightly, especially considering the craftsmanship typically associated with BEAM robotics (The "A" in "BEAM" is supposed to stand for "Aesthetics"). Nevertheless, I like the look of reincarnated techno-scrap. This fellow looks like it's crawling off a battlefield.
Click the image to see a video.
