Challenge Team Interim Report
Team Number: 032
School Name: Las Cruces Public Schools
Area of Science: Robotics
Project Title: The Little Robot That Could
Robots remain economically unreasonable due to the expense of
microcontrollers. Besides their high cost, microcontrollers also have low
amounts of memory, and slow processing speeds. Many people interested in
purchasing robots have access to a home computer. If the memory and
processing speed of the desktop computer could be harnessed to work with a
simple robotic device, then inexpensive robotic solutions could be made
To solve the problem of expensive robots, we are creating an inexpensive
robotic device, which will implement a simple microcontroller that will
communicate with a desktop computer. The desktop computer will then
interpret sensor data, and send commands back to the microcontroller.
Since the microcontroller will not be processing complex programs, it does
not need to be complex, nor expensive.
Progress to Date
To date we have determined the methods of creation and control of the
robot. We have researched multiple possibilities in all major aspects of
the robots construction and operation. The computer mapping procedures
have also been researched and defined.
We considered several types of robotic
mobility systems including the use of legs, wheels, or treads. From these
options we eventually chose treads. We chose not to use legs due to
several factors, the most important being their high cost for parts, and
time investment. Due to the complexity and the necessity of advanced
control systems, an excessive time investment would be required. We chose
not to use wheels due to their lack of versatility in different
environments. This led us to a solid conclusion to use treads because of
their low cost, durability, mobility, and simplicity.
The grapple and retrieval device will be a
two-fingered claw-like device that will be able to grab and lift
miscellaneous items that the robot will be sent to retrieve. The grapple
device would be able to lift an object off the ground just enough to
eliminate the friction of dragging the item. The tips of the grappling
device's fingers will have a rubber traction pads to allow the device to
grab onto most any surface, including smooth surfaces.
For our sensing equipment we considered
direct and indirect sensors. We decided not to use direct sensors due to
their inefficiency at mapping, and lack of versatility. Because of these
considerations, we decided to use and indirect sensing method. Viable
indirect sensing options included ultrasonic, visual, and laser/infrared
sensors. We decided not to use visual sensors because of the difficulty
interpreting the returned images. We decided not to use laser/infrared
sensors because of inefficiency of detecting objects that do not meet
certain parameters, such as opacity. Therefore we decided to use
Concerns of communications between the
robot and computer could be met with the use of a tethered, infrared, or
radio link. Our consideration for a tethered link was short lived, since
a tethered link would limit the range of the robot. While very
inexpensive, infrared links will not feasible work within a housing
confinement because it is limited to line of sight only. We finally chose
to use a radio link due to the fact that radio waves are not necessarily
confined to a single room, or line of sight.
Rewiring the toy tank is underway. The
toy tank must be modified to allow the microcontroller to have complete
control over the controls and motor functions of the toy tank. The
rewiring process requires the detection of what wires are used for the
functions of the toy tank, and then severing current connections to allow
the microcontroller to be given complete control.
For the issue of control systems we
decided to use a small onboard controller to handle mundane tasks, leaving
the computer to handle mapping and command functions. Out of the many
available onboard controllers, we chose to use a microcontroller in the
BASIC Stamp series. We chose to use a BASIC Stamp (IISX) because of the
simplicity to write a program for it, whereas other controllers required
programs to be written with an intimate knowledge of Assembly language.
We chose to use the BASIC Stamp IISX because of its speed, capacity, and
number of I/O lines.
The theories and methods for the mapping,
control, and communications that the computer will handle have been
decided. The software currently analyzes two differing maps to create a
composite map for the purposes of location identification. Functions for
the plotting of sonar readings have also been created. The GUI has also
been created, for ease of troubleshooting and data interpretation.
We expect to have a robot created from a motorized toy tank, modified to
include a Basic Stamp IISX microcontroller with a sonar range finder, 433
MHz RF transceiver, and a robotic gripping manipulator. A second 433 MHz
transceiver will be connected to the parallel port of the desktop computer
to facilitate communication between the robotic device and the computer.
Additionally, a computer program will be written that will map out areas
such as a living room or kitchen, and then allow the robot to seek and
find a requested item and then manipulate it. An example would be the
robot leaving the living room to enter the kitchen, then having the robot
find a soda can, pick it up, and bring it back to the living room.
- Michael Scoggin
- Stephen Miller