add pushbutton example

[challenge-bot] / README.md

# HBRC 2013 Challenge Robot

## Introduction

For 2013, it is proposed that there be a "club bot".
The goal is to learn from the 2011 "club bot" and
improve upon it.

Most introductory robots are "dead-end" robots that
tend to strand people after they have the first
few robot behaviors are implemented -- obstacle avoid,
wall follow, line follow, don't fall off table, etc.

One of the primary goals of the 2013 robot is to try
to make it expandable from simple to more complex in
reasonable incremental steps.

The base is organized around 1in x 1in grid peg-board
which is readily available from locations link Home
Depot, Lowes, and lumber stores.

There would be a variety of independent upgrades
that could be done in whatever order the user
feels inclined to use:

## Basic Platform:

The basic robot would be built in three phases:

### Phase 0: Arduino + Blinky LED's:
### Phase 1: Build Robot Platform
### Phase 2: Build TableTop Challenge Phase 1