Name:
Hecatonchires is named after the 100-armed monster of Greek mythology. It is so named for the four bumpers on the rover.

Goal:
All of my previous robots have had only two bumpers, one on the right front, and one on the left front. I always programmed them to back
up and turn when they bumped into something, but this usually resulted in backing into another obstacle and stalling the motors. I needed
bumpers on the back, but I was not willing to sacrifice my current to bumpers on the front. What is the solution?

Design:
This rover actually started with an idea to have two bumpers connected to only one sensor. The solution to my problem was to connect  a
front bumper and a back bumper together with a touch sensor using a combination of pusharms and levers. This way, when a bumper is
pushed in, the lever will push the touch sensor.

Building:
I began building on October 15, 2005. I had completed prototytpe the bumper assembly within a few hours. Few modifications were
necessary to fit the assembly into a robot. I then built the second bumper subassembly and connected them together. From the beginning,
I have had a stipulation that all of my robots be modular, so I then built a mounting fixture for the RCX. I used friction pins w/ bushings to
connect the RCX subassembly to the mountings. I then added two light sensors to the front of the robot two enable it to follow a line. The
last thing I built was the wheel and motor subassembly. I built this quickly, so it was not the most reliable subassembly I've ever built. But,
it worked. I was able to attach the left touch sensor to port 1, and the right touch sensor to port three. The left and right light sensors
connected to ports 1 and 3, respectively.

Program:
I programmed the robot in NQC. When I finished, it would roll around the room while searching for a dark line.If it found one, it would
follow the line until the line terminated or the robot ran into an obstacle. At this point, it would  back up, turn, and begin the process again.
Having the touch sensors and light sensors on the same ports turned out to be a great benefit. I did not have to create any override code for
the touch sensors to stop the line-following routine. When the touch sensor(s) were pressed, the light sensor reading disappeared until the
bumper was released. Built-in override! The other trouble spot I thought I might have was how to determine which of the two bumpers was
pressed. I decided I could be reasonably sure that if the motor on that side was moving forward, the front bumber woul be pressed, and vice
versa. This was relatively easy to program in by having a motor-change routine switch a variable based on the direction of the motor it was
changing to. This way, the bumper routine could simply check the state of the variable.

Lessons learned:
The decision to have four separate bumpers was very nice. It increased the chance of the robot completely avoiding obsacles.

~CK