Handy Board

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Handy Board
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Why the Handy Board

• Designed to be the controller of small, mobil
  robots
• Has many features that make it ideal for robotics
  projects
• Integrated motor drivers
• 32K bytes of memory
• LCD screen
• Integrated battery pack
• Interactive C
• Small size
• Sensor connectors for digital and analog sensors

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Handy Board Specifications

• Motorola 6811 microprocessor with system clock at
  2 MHz.
• 32K of battery-backed CMOS static RAM.
• Two L293D chips capable of driving four DC
  motors.
• 16 x 2 character LCD screen.
• Two user programmable buttons, one knob and one
  piezo beeper.
• Powered header inputs for 7 analog sensors and 9
  digital sensors.

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Handy Board Specifications

• Internal 9.6v nicad battery with built in
  recharging circuit.
• Hardware 38 kHz oscillator and drive transistor
  for IR output and on-board 38 kHz IR receiver.
• 8-pin powered connector to 6811 SPI circuit.
• Expansion bus with chip selects.
• 4.25 x 3.15 inches.

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Handy Board
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Expansion Board Specifications

• 10 additional analog sensor inputs
• 4 inputs for active LEGO sensors (reflectance
  sensor and shaft encoder).
• 9 digital outputs.
• 6 servo motor control signals with power supply
  from the Handy Board's internal battery.
• optional external power for servo motors.

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Expansion Board Specifications

• connector mount for Polaroid 6500 ultrasonic
  ranging system.
• pass-through connector for the Handy Board's LCD
  screen.

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Expansion Board
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Charging

• Adapter plugged directly into board.
  trickle-charge. (12-14 hours)
• Adapter plugged into the Serial Interface/Battery
  Charger board with NORMAL CHARGE selected.
  Trickle-charge (12-14 hours)
• Adapter plugged into the Serial Interface/Battery
  Charger board with ZAP CHARGE selected. Zap
  Charge mode (3 hours. DO NOT LEAVE IN THIS MODE)

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Downloaders

• Two primary components to Interactive C
• 6811 downloader program
• Interactive C application
• Program named pcode_hb.s19 must be present in
  the handy board to use Interactive C.
• Bootstrap Mode
• Turn off the board and then turn it on while
  holding down the stop button. When the two power
  LEDs go out it is in bootstrap mode.

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Interactive C

• A subset of C
• Includes control structures, local and global
  variables, arrays, pointers, integers and
  floating point numbers
• Data types
• Int 16-bit integers
• Long 32-bit integers
• Float 32-bit floating point
• Char 8-bit characters
• No switch statements

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Using IC

• IC will perform any valid C statement
• 22
• beep(), sleep(2.0)beep()
• Main function
• If main function is present it will be run when
  the Handy Board is reset

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Using IC

• IC commands
• load ltfilenamegt compiles and loads filename to
  the Handy Board
• unload ltfilenamegt unloads filename and
  re-loads remaining files
• list files, list functions, list globals lists
  files, functions or globals presently on the
  Handy Board
• kill_all kills all currently running processes
• Ps prints the status of currently running
  processes
• Help displays a help screen of IC commands
• Quit exits IC

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Library functions

• DC Motors
• void fd(int m) turns on motor m in forward
  direction
• void bk(int m) turns on motor m in backward
  direction
• void off(int m) turns off motor m
• void alloff() turns off all motors
• void ao() turns off all motors
• void motor(int m, int p) turns on motor m to
  power level p (p ranges from 100 to -100 or full
  forward to full backwards)

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Library functions

• Sensor input
• int digital(int p) returns true false value of
  sensor in sensor port p
• int analog(int p) returns value of sensor in
  sensor port p (value between 0 and 255)
• User Buttons and knobs
• int stop_button() returns value of STOP button
  (1pressed,0relesed)
• int start_button() returns value of START button
  (1pressed,0relesed)
• void stop_press() waits for STOP button to be
  pressed, then relesed and then issues a short
  beep and returns
• void start_press() waits for START button to be
  pressed, then relesed and then issues a short
  beep and returns
• int knob() returns the position of the knob as a
  value from 0 to 255

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Library functions

• Time Commands
• void reset_system_time() sets system time to
  zero
• long mseconds() returns system time in
  milliseconds
• float seconds() returns system time in seconds
• void sleep(float sec) sleeps for sec seconds
• void msleep (long msec) sleeps for msec
  milliseconds

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Library functions

• Tone Functions
• void beep() produces a 500 Hertz tone for .3
  seconds
• void tone(float frequency, float length)
  produces a tone at frequency Hertz for length
  seconds
• void set_beeper_pitch(float frequency) sets the
  beeper tone to frequency Hertz
• void beeper_on() turns on the beeper
• void beeper_off() turns off the beeper

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Library Functions

• Process Functions
• int start_process(function-call(), ticks,
  stack-size) returns an intiger process ID
  assigned to the new process
• int kill_process(int pid) returns a 0 if the
  process was destroyed, 1 if the process cannot be
  found
• void hog_processor() adds additional 256 ms to
  currently running process
• void defer() process swaps out imediately after
  this function is called

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Analog and Digital Sensor Inputs

• Two banks sensor inputs
• nine digital sensor inputs
• seven analog sensor inputs

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Sensor Circuitry

• Each port is a 3-wire sensor (power, ground,
  signal)
• 47K resistor provides half of a common voltage
  divider circuit
• Default 5 volts when no signal is present

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Sensor Inputs

• Digital Inputs
• True/False (Vsensgt2.5/Vsenslt2.5)
• Analog Inputs
• Range from 0 to 5 volts
• Converted to 8-bit number
• 0 to 255 decimal

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Switch

• Simple switch circuit
• -contact switch

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Voltage Divider

• Simple voltage divider circuit
• Light sensors
• Reflectance sensors

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Reflectance Sensor

• Emitter led
• Current limiting resistor
• Detector/photoresistor
• Concept directly applies to Break beam sensors

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Optical Distance Sensor GP2D12

• Modulated IR emitter
• Projects a spot of modulated light onto target
  surface
• Detector assembly
• Light from the spot is focused by the detector
  lens
• The focused light hits a special linear
  position-sensitive detector element

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Optical Distance Sensor

• The angle of incidence changes depending on the
  distance the light spot on target surface is from
  the Lens/Position Sensitive Detector

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Hamamatsu UVTron

• Sensor
• Detects radiant energy int the 185-260nm range
• Pulses when it absorbs radiation.
• Driver Circuit
• Monitors pulses from sensor and signals high when
  a set number of pulses have been detected.

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Gears

• Uses
• To reverse the direction of rotation
• To increase or decrease the speed of rotation
• To move rotational motion to a different axis
• To keep the rotation of two axis synchronized
• Tradeoffs of increasing/decreasing speed
• Gearing for high speed reduces torque
• Gearing for high torque reduces speed

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Gears

• Gear Ratios
• Representation of the size difference between the
  two gears 21 (two to one)
• The smaller gear has to spin two times for the
  larger gear to spin a single time
• Gear Trains
• Combination of multiple gears
• Produce larger gear ratios
• Change axis of rotation
• Synchronize gears

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Lab

• Ferguson room 18
• Equipment
• Computers
• Voltage Supplies
• Voltage Meters
• Oscilloscopes
• Soldering equipment
• Wave Generators
• Manuals located in workbench drawers

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BrainStem

• 40 Mhz RISC processor
• 5 channel, 10 bit A/D
• 5 digital I/O lines
• GP2D02 Driver
• 1 MBit IIC port
• IIC routing
• status LED

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BrainStem

• 10, 1k TEA files
• RS-232 serial port
• reflex architecture
• 4 concurrent TEA processes
• 4 high resolution servo outputs
• Onboard 1 Amp, 5V power regulation (low dropout)

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TEA

• Tiny Embedded Application
• Exact subset of ANSI C
• Runs on the TEA VM (virtual matine)

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References

• Robotic Explorations A Hands-On Introduction to
  Engineering by Fred G. Martin
• http//handyboard.com/
• http//www.cse.unl.edu/bradleyk/lego.htm

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Questions