Transcript Tutorial on LEGO robots, Handy Board, and Ferg 18 lab

Handy Board
Why the Handy Board
• Designed to be the controller of small, mobil
robots
• Has many features that make it ideal for robotics
projects
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Integrated motor drivers
32K bytes of memory
LCD screen
Integrated battery pack
Interactive C
Small size
Sensor connectors for digital and analog sensors
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.
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.
Handy Board
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.
Expansion Board Specifications
• connector mount for Polaroid 6500
ultrasonic ranging system.
• pass-through connector for the Handy
Board's LCD screen.
Expansion Board
Charging
• Adapter plugged directly into board. tricklecharge
• Adapter plugged into the Serial Interface/Battery
Charger board with “NORMAL CHARGE”
selected. Trickle-charge
• Adapter plugged into the Serial Interface/Batter
Charger board with “ZAP CHARGE” selected.
Zap Charge mode
Downloaders
• Two primary components to Interactive C
– 6811 downloader program
– Interactive C application
• “pcode_hb.s19” must be present in the handy
board to use Interactive C.
• Bootstrap Mode
– Turn off the board ant then turn it on while holding
down the stop button. When the two power LEDs go
out it is in bootstrap mode.
Interactive C
• A subset of C
• Includes control structures, local and global
variables, arrays, pointers integers and floating
point numbers
• Data types
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Int 16-bit integers
Long 32-bit integers
Float 32-bit floating point
Char 8-bit characters
• No switch statements
Using IC
• IC will perform any valid C statement
– 2+2;
– (beep(), sleep(2.0);beep()};
• Main function
– If main function is present it will be run
when the Handy Board is reset
Using IC
• IC commands
– load <filename> compiles and loads “filename” to the
Handy Board
– unload <filename> 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
Library functions
• DC Motors
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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)
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
(1=pressed,0=relesed)
– int start_button() returns value of START button
(1=pressed,0=relesed)
– 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
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
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
Analog and Digital Sensor Inputs
• Two banks sensor
inputs
– nine digital sensor
inputs
– seven analog sensor
inputs
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
Sensor Inputs
• Digital Inputs
– True/False (Vsens>2.5/Vsens<2.5)
• Analog Inputs
– Range from 0 to 5 volts
– Converted to 8-bit number
– 0 to 255 decimal
Switch
• Simple switch circuit
-contact switch
Voltage Divider
• Simple voltage divider
circuit
– Light sensors
– Reflectance sensors
Reflectance Sensor
• Emitter led
• Current limiting
resistor
• Detector/photoresistor
• Concept directly
applies to Break beam
sensors
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 positionsensitive detector element
Optical Distance Sensor
• The angle of incidence changes depending
on the distance the light spot on target
surface is from the Detector Lens/Position
Sensitive Detector
Gears
• Uses
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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
Gears
• Gear Ratios
– Representation of the size difference between the two
gears 2:1 (two to one)
– The smaller gear has to spin two times for the larger
gear to spin a single time
• Gear Trains
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Combination of multiple gears
Produce larger gear ratios
Change axis of rotation
Synchronize gears
Lab
• Ferguson room 18
• Equipment
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Computers
Voltage Supplies
Voltage Meters
Oscilloscopes
Soldering equipment
Wave Generators
Manuals located in workbench drawers
References
• Robotic Explorations A Hands-On
Introduction to Engineering by Fred G.
Martin
• http://handyboard.com/
• http://www.cse.unl.edu/~bradleyk/lego.htm
Questions