Question 1: What was the general strategy or plan behind your bot design?

After the surprising success of Mini-Skirt, I decided I should attempt to design out its flaws. This resulted in Mini-Skirt Jr., which competed at Science Central's Summer games. Mini-Skirt Jr. didn't do so well, in fact, it lost all of its matches. This experience caused me to rethink the paper skirt altogether. Most of the robots that Mini-Skirt Jr. faced had very long scoops or wedges on their front-end. Some didn't even use sensors to detect the ring edge. In preparation for Sumo-bot 5, I decided to take out the physical skirt and replace it with a light skirt. The idea was that the standard light sensor is looking for changes in light intensity, so adding more light should trick it in the same way as it seeing the paper skirt did.

After thinking about the construction of the robot a bit, I decided to make the light skirt a module that could be swapped out if needed. At the same time I was thinking about the way Mini-Skirt lost to Knife and how I might be able to beat Knife this time around. I decided that it might be possible to build a stealth module that might allow me to "hide" from Knife. This is how the module "SPIKE" came about.

So in the end the strategy became: trick the opponents that use a light sensor with the light skirt, if facing Knife, swap to the SPIKE module and hope for the best.

Question 2: What technologies/mechanisms did you use?

I used 40, 12 volt, incandescent lamps purchased from a train hobby shop to make HALO. I also used a 12 volt battery holder purchased from Radio Shack. I decided I wanted to focus the light down towards the surface of the ring, so I added standard LEGO flags and the plates they attach to.

For SPIKE I used 180, blue, LEGO pyramid pieces. The idea for this module came to me at work. My former employer has a sound chamber in which they test the high-frequency electronics devices they design and build. The idea is that the shape and color of the cones allows the sound waves to approached and deflect off, but instead of bouncing back towards the source they bounce towards the neighboring cone. As the wave travels the length of the cone, the energy it carries gets lost in all off the collisions, eventually silencing it.

Question 3: What was the most challenging aspect of construction?

Well, I am not so good with a soldering iron, so having to manufacture the HALO myself was a bit tough. Also, I originally wanted an Ultra-Sonic beacon (emitter) to be hanging behind SPIKE as a lure for Knife, it was quite a challenge trying to have one built for me. In the end, it never got built.

Question 4: Are there any special features you care to talk about?

Although neither of the modules performed as planned (HALO didn't trick any of the robots and SPIKE was easily found by Knife) I am particularly proud of the modularity of the whole robot. It was a simple matter to swap out HALO for SPIKE because of how I constructed the base robot. It is based on the explorer bot that is in the RIS constructopedia. A very small and simple chassis that would allow for heavier modules to be added.

Question 5: What surprised you about how your bot behaved/performed during the event?

Going into the event I wasn't actually expecting too much from Mini-Skirt 3. I had a feeling the lights weren't going to be very effective because many of the robots had faced the original Mini-Skirt. This experience allowed the builders to reposition their light sensors so they wouldn't get tricked. Also, being untested, I had my doubts about the effectiveness of SPIKE against the ultra-sonic sensor.

It occurred to me during the event that the skirt idea may have run its course. Mini-Skirt 3 is likely to be the last in the line.