Building the Future

1
Building the Future

• John Wang Diana Holcomb

2
Conference Robot

• We wanted to make a robot that, when placed on a
  conference table, would be able to detect who is
  speaking, drive in their direction, and videotape
  them without falling off the table.

3
How

• Take the standard growbot, add two microphones
  and a small camera, and modify the touch sensor.

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Growbot Info
5
More Fun Growbot Facts

• Built on a brushed aluminum chassis that provides
  a sturdy platform for the servo motors and
  printed circuit board.
• Mounting holes and slots may be used to add
  custom robotic equipment.
• Rear wheel is a drilled polyethylene ball held in
  place with a cotter pin. wheels are machined to
  fit precisely on the servo spline and held in
  place with a small screw.
• GrowBot kit is built on a PCB with defined
  locations for electronic components.
• Kit accepts Parallax AppMods in two locations to
  provide expansion capabilities.
• Other possible growbot activities include follow
  a line, solve a maze, follow light, or
  communicate with another robot.

6
Growbot Building

• LOTS of soldering!
• In some cases, instructions were very vague.
  There should be more diagrams.
• Time consuming.

7
Finished Growbot

• This is a picture of the back, top, and bottom.
• Growbot seems a little shaky, and its difficult
  to line up the wheels.

8
Programming

• Growbot is programmed in basic
• Operation is easy, as the growbot has an on/off
  switch, enabling quick program download and
  running.
• The robot hooks up to the computer using the
  serial port.

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The GrowBot's Brain The STAMP

• In addition to a PIC microcontroller chip
  (single-chip microcomputer with on-chip memory
  and input/output pins for controlling external
  devices), the STAMP module has a non-volatile
  memory 2048-byte EEPROM chip that hold a
  compressed version of a user program written in
  PBASIC (Parallax's BASIC-like language for the
  STAMP).
• A PBASIC interpreter program resides inside the
  PIC microcontroller chip itself - it reads and
  interprets the PBASIC tokens stored in the
  external EEPROM chip one at a time, and executes
  the appropriate low-level operations. In the
  GrowBot's STAMPII module, the PIC runs off a 20
  MHz crystal clock, and can execute on average
  about 4000 PBASIC program instructions per
  second. If you are sensing input pins and
  controlling output pins, you will be able to do
  this at a rate of about 50 times per second for a
  typical program.
• The STAMP II module has 16 input-output pins, of
  which 10 are already used on the GrowBot for
  specific functions (like lighting left and right
  LED's, driving left and right wheel motors,
  etc.). The remaining 6 I/O's may be connected to
  user-designed external circuitry.
• Each I/O pin can be defined to be either an input
  or an output. Inputs should be connected to
  sensor circuits that drive a voltage onto the pin
  - the logic level of this voltage (logic 0 if Vin
  lt 1.5 volts, and logic 1 if Vin gt 1.5 volts) can
  be read into the PBAISC program through the
  pre-defined PBASIC variable INi, where i is the
  I/O pin number. Outputs should be connected to
  devices or circuits that are to be driven either
  high (logic 1 5 volts) or low (logic 0 0
  volts). This can be done using PBASIC assignment
  statements, as in OUTi 1, or OUTi 0, or
  alternatively, using HIGH OUTi, or LOW OUT i.
  This simple program input-output allows for a
  wide variety of sensing and control applications.
  

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The GrowBot's Brain The STAMP
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What the program does

• The threshold of two microphones is set to detect
  talking from random background noise.
• The motors are set so that the opposite motor
  from the microphone picking up the loudest volume
  will go the fastest. In other words, the robot
  is always turning in the direction of the loudest
  noise. we are assuming that the speaker will be
  the hopefully the only, or at least the loudest,
  person talking.
• The video on top of the robot will be facing
  directly ahead to videotape whatever the robot
  approaches.
• The touch sensor is modified to point downward a
  few inches in front of the robot, so that the
  robot only moves if it is pressed. Once the
  sensor encounters and edge, the robot will back
  up a few inches and wait until a noise is
  detected that will take it in another direction.

12
Random Pictures