Straight outta the Portfolio: Steve-V1-Der

Steve-V1-der was the first “robot” I ever built on my own.  With uthermal, of course, but still, it was a lot on my own. A very simple design, it was made with saws and drills and things that could be bought at home depot or radioshack (the exception being the Solarbotics wheels and motors).

 

Mid-Stage Steve-V1-Der

The National Science Olympiad Robot Ramble competition for 2008 was to collect a variety of objects and place them into a square box. The objects included tennis balls, D-cell batteries, and a notecards. Additional points were awarded if the 3 balloons in the box were popped. A time limit of 3 minutes was placed, and tethered robots were allowed.

After watching previous years designs fail due to complexity and being limited by expensive wireless controllers with 4 channels, my friend and I decided to go for a simple, tethered design with zero ICs or complex circuitry. Non-toggling rocker switches were wired in such a fashion to allow us reversible current flow through the motors, and they were directly wired to the battery pack and motors. These switches were in turn placed inside of a simple plastic project box from Radio Shack that had the battery packs velcro’d onto the back. There were 3 total switches, 2 for control of the drive train and the third for the actuator.

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The robot itself was equally simple in design. The frame was bolted-together 1” angle aluminum stock, cut with a hacksaw to the sizes we needed. The motors were cheap Solarbotics Gear Motors with integrated wheels, with 4 wheels being dedicated to driving the robot. The scoring device was a simple Plexiglas ramp with 2 modified drawer sliders spanning the length of the robot, from the lower front edge to the top rear edge. The drawer-sliders were connected via a c-shaped cart, from which a spring-loaded “door” was hinged. The far end of the door had 2 lengths of high-strength fishing line attached to it which ran to a powered spindle underneath the ramp. When the spindle was fully out, the cart would be at the bottom of the ramp, with the door extended out, allowing objects to pass into the C-shaped cart. When the spindle was pulled in, the door would swing in, push the collected objects into the cart, and begin to pull the cart, door, and objects up the Plexiglas face. Gravity would carry the cart back down when the spindle was released; allowing us to create a very simple robot that only required 3 points of actuation. To pop the balloons, we had pre-loaded the cart with Styrofoam balls filled with T-pins (pointy end out). Our first move would be to drop these “spikey balls of death” into the box, popping the balloons effortlessly without any need for another actuator. This robot we called Steve-V1-Der (Stevie Wonder) in honor of our team mentor, Stephen Orr.

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For our next version of the robot, we based our strategy off of one we had seen online. The robot had collected all of the objects together outside of the box, then picked up the box and placed it on top of them. We kept the same tethered rocker-switch control scheme for this one, and upgraded all of our motors to try to gain more speed and power. The new robot also had the bolted aluminum angle stock frame, and now had the drawer sliders up front and vertical, resembling a fork-lift. With this design, we were easily able to pick up a Plexiglas scoring box and shuffle all of the objects together. We named this robot Steve-V2-Der (Stevie Tudor).

The regional competition for Steve-V1-Der had a very non-standard field, which consisted of a heavy wooden scoring box and shag carpet. Many of our competitors had used VEX systems or other heavy metal frames, and found themselves unable to move in the carpet at all. The light aluminum frame, simple design, large wheels, and off-board batteries of Steve-V1-Der were able to easily maneuver the shag carpet, collect all of the objects and place them into the scoring box. None of the other 3 competing teams were able to score at all, making Steve-V1-Der win by a landslide.

Steve-V2-Der was a redesign for the national competition, and proved to be less-successful than his predecessor. The national competition also had a non-standard field that also had a heavy wooden scoring box that Steve-V2-Der was unable to pick up (few of the other competitors were able to pick it up either). It placed 36th nationally, whereas the simplicity of Steve-V1-Der would have fared far better.

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