The story of our bug-catching spider automaton goes like this: A giant evil spider resides in a big web. One day an unfortunate lady bug gets trapped in the web and the scary spider pounces on it.
We came up with the idea for this six-week project together and discussed implementation possibilities at length, particularly with respect to moving the spider and detecting the bug. For example, although we ended up using IR sensing for bug detection, we considered several other possibilities including touch sensors and image processing. At that point, the highly modular and reusable nature of the project components allowed us to build separately, and we are posting our Instructable as a two-part series.
Part 1, described in this Instructable, shows how to build the following elements:
* The frame to which everything is attached
* The spider web and associated lighting
* The spider mover, which is an XY table beneath the web
Part 2 shows how to build the remaining elements:
* The bug
* The bug detector
* The spider
Please note that due to a course deadline, the Part 1 Instructable was published before the documentation was complete, so watch for ongoing updates to the later steps.
Readers who would like to build this project should be aware of the following limitations
The XY table moves nicely under human power, but not with the servos, and we think this outcome is a result of the materials not being sufficiently rigid. It's possible that adding another servo to move the lower slider from both sides would be helpful, too. Here are some alternative Instructables XY tables to try:
Low Cost Hobby Servo XY Table
Internet Arduino-Controlled T-Slot XY Table
DIY CNC Router
Our intent was to be able to display the web in any position, such as leaning against a wall. For this reason, we used strong magnets on both the spider and the mover. Although this idea worked well with models during pretesting, the final spider clings too tightly to the web and doesn't move well. For this reason, we would recommend a different spider / mover magnetic connection, as well as stronger servos to help overcome drag.
The spider's orientation is fixed. We had discussed using a rotating arm on the spider mover, with the pivot point toward the front of the spider, but did not build it due to time limitations. This arm would have allowed the spider to turn as it moved forward along an arc traced out by the spider mover.