Transcript Botball 2001 Tutorial

Robotics: Integrated Systems Design
Handy Board Robot Kit Tutorial
Slides modified from Botball 2004 Workshop
©1993-2004 KISS Institute for Practical Robotics
and
CMU General Robotics Class
Written by Jason Geist
Handy Board Setup
Interface Cable
(4 wire phone cord)
Serial Cable
Charger:
12V - 500 mA
Interface Board
(with charger)
Handy Board (w/ expansion)
Power Supply:
9.6V NiCad Battery Pack
Charging HB Batteries
•
Charging is best accomplished through the interface board
–
•
•
The interface board has 2 modes: Normal Mode, ZAP Mode
In Normal Mode, the yellow light on the interface board is lit
–
•
There is also an on-HB charge port (a trickle charge)
A full charge takes about 12 hours, though you can use the board earlier.
ZAP mode fully charges a turned off HB in 2 hours (the yellow light is NOT lit)
–
Warning: if ZAP mode is used for more than 2 hours (or fraction thereof for a charged
battery), it
•
•
–
may damage the batteries
will eventually destroy the HB (via heat from battery overcharging)
NEVER use ZAP unattended.
•
ZAP is ONLY recommended while working with the HB while it is on, or if your battery is very
low.
You fry it, you buy it!
Interactive C
•
•
•
•
•
•
IC4 is a C compiler/interpreter
Implements most of the ANSI C language
Runs on Handy Board and LEGO RCX
Loads firmware onto board
Provides an editor and documentation
Provides an interactive environment for testing
and debugging
• Built-in IC Manual
• Check www.kipr.org/ic for the most current
version
Download the Firmware
• Make sure your Handy Board is connected to your
personal computer via 4-pin modular cable, serial interface
box and serial port cable (and a USB to serial converter if
needed)
• Select Change controller type from the Settings
menu and select the Handy Board
• Select Download Firmware from the Settings
menu
• Select the appropriate serial port
• Click on Download Firmware button
• Follow the onscreen directions
Handy Board (with expansion)
off
power switch
on
download
connector
sonar
(uses 2 ports)
red (# 0)
gray (digital 7)
0
1
motor ports
(3 pins each)
2
3
0
1
2
3
4
5
servo ports
(wire order B|R|Y)
digital analog
lo-batt
ports ports
START & STOP LED
(7-15)
(2-6)
buttons
power LED
(off in download mode)
charge port
(under exp board)
knob (under
exp board)
floating analog
ports (16-19)
analog
ports IR receiver
(20-23)
Handy Board Sensors
•
•
The knob, Start button, and Stop button are built-in sensors
Detachable sensors use a keyed connector (2 wire or 3 wire)
– Analog sensors:
• Light (ports 2-6, 20-23)
• IR reflectance (ports 2-6, 20-23)
– Floating analog sensors:
• Optical rangefinder (ports 16-19)
– Digital sensors:
• Touch (ports 7-15)
• Slotted encoder (ports 7,8,12 & 13)
– Special sensors:
• Ultrasonic rangefinder (sonar)
–
gray-7, red-0 on expansion board
• Camera (CMU)
–
–
3 pin connector in any open sensor port
Phone cable in HB serial port
Handy Board DC Motors
• Black gear motor with gray cable
plugs directly into HB motor port high torque and medium speed
• Motors with Lego connectors are
connected to the HB using Lego-HB
motor wires
• High speed, medium torque gear
motors (gray Lego)
• Low speed, low torque gear motor
(red Lego)
Handy Board Servos
• Plug-in order is black, red,
yellow with black toward the
expansion board edge (left)
• Servo plugs are pins sticking out
of expansion board
• Servos in packages are standard
position servos
• Servo with trim knob is a speed
servo
Handy Board Plugs
Keyed plug (digital
and analog ports)
DC motor plug (motor ports)
Servo motor plug (servo ports)
Testing Your HB, Sensors & Motors
• Turn the Handy Board off and then back on to start the
program (follow the onscreen instructions using the knob and
start and stop buttons)
• Connect and test motors
• Connect and test digital sensors
• Connect and test analog sensors (be sure you have the right
type of sensors in the right ports)
• Connect and test the sonar sensor
• Connect and test servos (one at a time)
• Connect and test the dongle and CMUcam (see next slide)
CMUcam Setup
To HB
The dongle switch has three
positions:
To Dongle’s
red end
To PC
CMUcam keyed
connector (powers the
camera) goes to any
keyed port on the HB
– Switch at red end: HB talks
to CMUcam
– Switch at gray end: HB
talks through
charge/interface board to
PC
– Switch in middle:
CMUcam talks through
charge interface board to
PC
– The HB continues to charge
no matter what the switch
position
Charging the HB With the
CMUcam Connected
• The CMUcam uses as much power as the HB
• Together they use more power than is supplied by normal
charge
• When the camera is connected and the HB is turned on, it
is useful to have the charger in ZAP mode. The charger
may be left in ZAP for a few minutes, even if the HB is
turned off.
• ALWAYS reset the charger to normal mode and turn
off the HB when you leave the HB unattended!
Interacting with IC
• Click on the Interaction tab
• Just type into area at bottom of IC window
• Simple expressions
9/5;
• Making noise
beep();
• Printing to the LCD screen
printf("I’m printing!!\n");
#use Preprocessor Statement
• #use is a preprocessor directive
– Preprocessor directives start in column 1 with the “#” symbol
• Purpose of #use
– Program blocks may be saved in multiple files
– Before IC can compile a user’s program, the IC preprocessor has to
gather together all of the program files
– The #use directive is needed to tell the preprocessor where to find
files when multiple files are being used
• Example
#use "globals.ic"
#use "motorfns.ic"
void main () { . . .
• WARNING!! Preprocessor directives are terminated by the
end of the line, not a semi-colon. When putting in a comment
on a preprocessor directive's line, be sure to either put it on its
own line or use /* comment */ (not // comment )
IC: Processes
• IC functions can be run as processes operating in parallel (along with
main)
– The computer processor is actually shared among the active
processes
– main is always an active process
– Each process, in turn, gets a slice of processing time (5ms)
• A process, once started, continues until it has received enough
processing time to finish (or until it is “killed” by another process)
• Global variables are used for interprocess communications
IC: Functions vs. Processes
• Functions are called sequentially
• Processes can be run simultaneously
– start_process(function-call);
• returns the process-id
• processes halt when function exits or parent process exits
– processes can be halted by using
kill_process(process_id);
• hog_processor(); allows a process to take over the
CPU for several seconds until it finishes or defers
• defer(); causes process to give up the rest of its time
slice until next time
IC: Process Example
#use pause.ic
int done; /* global variable
for interprocess communication */
void main()
{
pause();
done=0;
start_process (ao_when_stop());
. . . more code (involving motor operation) . . .
}
void ao_when_stop()
{
while (stop_button() == 0); /* wait for stop button */
done=1;
/* signal other processes */
ao();
/* stop all motors */
}
Structure
• LEGO bricks are finicky:
–
–
–
–
They HATE duct tape.
They HATE hot glue.
They HATE super glue.
They HATE epoxy.
• You should never need adhesives to build
reliable LEGO structures
Basic Mounting Frame
• Servos may have
a piece of LEGO
glued to each
side
• However, in
many cases you
can use a LEGO
frame like this to
securely mount a
servo or black
gear motor
without using
any glue
Picture courtesy of Terry Grant
The Servo fits snugly in frame
Picture courtesy of Terry Grant
Mounting a 24T Gear
• You can use the
accessories that come
with the servos to
securely mount a 24
tooth gear the servo or
black gear motor
Picture courtesy of Terry Grant
Mounting a 40T gear
• The 40 tooth gear can
be screwed onto one
of the servo horns for
a reliable mount.
Picture courtesy of Terry Grant
Gear motor with 24T gear in the
Frame
Picture courtesy of Terry Grant
Philosophy
•
•
•
•
Have fun
Be creative, unique
Strive for cool solutions, that work!
Aesthetics: it’s fun to make beautiful
robots!
Sensor Types
• Digital:
– Return a 0 or a 1
– Switches or bumpers are an example
(open: 0, or closed: 1)
• Analog:
– Sensor returns a continuum of values
– Processor digitizes results (8 bits give values of 0-255)
– e.g. light sensors
Light Sensors
•
•
•
•
•
•
Analog sensor
Connect to ports 2-6 or 20-23
Access with function analog(port#)
Low values indicate bright light
High values indicate low light
Sensor is somewhat directional and can be made
more so using black paper or tape or an opaque
straw or lego to shade extraneous light. Sensor
can be attenuated by placing paper in front.
IR Reflectance Sensor “Top Hat”
•
•
•
•
Analog sensor
Connect to ports 2-6 or 20-23
Access with function analog(port#)
Low values indicate bright light, light
color, or close proximity
• High values indicate low light, dark
color, or distance of several inches
• Sensor has a reflectance range of about 3
inches
Optical Rangefinder “ET”
•
•
•
•
•
Floating analog sensor
Connect to ports 16-19
Access with function analog(port#)
Low values indicate large distance
High values indicate distance approaching
~4 inches
• Range is 4-30 inches. Result is
approximately 1/d2. Objects closer than 4
inches will appear to be far away.
Ultrasonic Rangefinder (Sonar)
• Timed analog sensor
• Another Position Sensing Device
• Connect red to Expansion board
– (upper deck) port #0
•
•
•
•
•
Connect gray to Digital #7
Access with function sonar()
Returned value is distance in mm to closest object in field of view
Range is approximately 30-2000mm
No return (because objects are too close or too far) gives value of
32767
• Wait at least .03 seconds between sonar()calls
Touch Sensors
• Digital sensor
• Connect to ports 7-15
• Access with function
digital(port#)
• Three types
• 1 indicates switch is closed
• 0 indicates switch is open
• These make good bumpers and
can be used for limit switches on
an actuator
Slot Sensors
• Digital (breakbeam) sensor
• Connect to ports 7, 8, 12 or 13
• Access with function
digital(port#)
• 1 indicates slot is empty
• 0 indicates slot is blocked
• These can be used much like touch
sensors (if the object being touched fits
in the slot)
• Special abilities when used as encoders
Wheel Encoders
• Two types of wheel encoders
reflectance
sensor
slot
sensor
• Note that there are two transitions per rotation (dark to
light and light to dark)
Using Encoders
•
For a striped encoder wheel
– with the RCX use the Lego light sensor
– with the Handy Board use the top hat reflectance sensor
•
•
•
For a perforated encoder wheel, use the slot sensor (HB only)
Connect to ports 7, 8, 12, 13 (encoder# is 0, 1, 2, 3)
On the RCX ports 1, 2 or 3 (encoder# is 1, 2, 3)
enable_encoder(encoder#);
– enable an encoder only once...unless you disable it between enables
disable_encoder(encoder#);
read_encoder(encoder#);
The HB slot sensor
– returns the number of transitions
will fit across a Lego
wedge belt wheel
reset_encoder(encoder#);
– sets that encoder’s count back to 0
•
On the RCX with a light sensor
encoderblack(encoder#);
encoderwhite(encoder#);
– used to calibrate light and dark values of a striped encoder wheel
Simple Encoder Program
void main(){
int enc1, enc2;
enable_encoder(1); // turn on the encoders; sensors
// plugged into ports 8 & 12 on HB or
// 1 & 2 on RCX
enable_encoder(2);
while(!stop_button())
{
enc1=read_encoder(1); /* read each encoder */
enc2=read_encoder(2); /* and show values
*/
printf("Enc1=%d Enc2=%d\n",enc1, enc2);
sleep(0.1); /* wait a bit and do it again */
}
}
Mounting a slot sensor encoder
Carefully align
sensor with
encoder wheel
Built-in Sensors: Knob
• Knob: the knob is a potentiometer which is
treated like an analog sensor
– The access function knob() returns 0-255
– Can be used for adjusting values during runtime
Built-in Sensors: Start
• Start Button:
– Access function start_button()returns 1 while
pressed, 0 otherwise
– Holding down Start while powering the board will
bypass executing main.
– When downloading a new program, it is always good
practice to hold down the start button and power up
the Handy Board before pressing the download
button on IC
Built-in Sensors: Stop
• Stop Button:
– Access function stop_button()returns 1
while pressed, 0 otherwise
– Holding down Stop while powering the board
will put the board in download-firmware
mode. This is necessary for loading the
firmware.
DC Motors
• High speed, medium torque gear motors (gray
Lego)
– Use Lego-Lego cables from motor hotspot to
RCX
– Connected to the HB using Lego-HB motor
wires
• Low speed, low torque gear motor (red Lego)
– Connected the same way as the gray Lego
motors
• Use Motor channels 0, 1, 2 & 3 on the HB and
1, 2 & 3 on the RCX
• Full Forward: fd(1);
• Full Reverse: bk(1);
• 2/3 Reverse: motor(1,-66);
– Note: the RCX only has only 7 distinct PWM
power settings spread over the values from 0 to
100 (and for 0 to -100)
More DC Motors
• Medium speed, High
torque motors resemble
servos -- but they are not
• Motors with gray cables
plug into the Handy Board
• Motors with a black cable
are for the RCX or by
using a Lego-HB motor
wire can be connected to
the Handy Board
Handy Board Position Servos
•
Plug-in order in the servo ports is black, red, yellow
with black toward the expansion board edge (left)
– You can remember this by associating it with
alphabetic order (black, red, yellow)
•
•
•
Enable Servos:
init_expbd_servos(1);
(activates all 6 servo ports)
Disable Servos:
init_expbd_servos(0);
(de-activates all 6 servo ports)
Servos’ positions are set by the globals
servo0,servo1,…,servo5
(these are predefined global variables and
correspond to the servo ports)
– Save power by limiting values to
•
the range [1000, 3900]
Note: Servos acting weird or not
working indicates the battery is low
cmucamlib Routines
• To use any camera routines, be sure to put
#use "cmucamlib.ic" at the top of your file
• Call init_camera(); to initialize camera before any
other camera calls -- will beep and complain if HB cannot
talk to camera (check the dongle switch)
• Use clamp_camera_yuv(); to automatically set
camera for the current lighting conditions. Camera should
be pointed at a white surface when this call is being made
(it waits for start button to be pressed). It takes 15 seconds
for this function to complete!
cmucamlib Routines (cont.)
• Call track_blue(); &
track_orange(); to check for color
blobs that CMUcam can see. These
functions return 0 if they find no color blob,
or the confidence of the blob detected. A
good confidence is 80 and up. A confidence
of 4 or 5 is poor.
cmucamlib Routines (cont.)
• The track_color information is stored in globals:
track_size stores the approximate number of pixels matching
in the blob
track_x stores the pixel x coordinate of the centroid of the color
blob
track_y stores the pixel y coordinate of the color blob (note:
0,0 is the center; 40,80 is upper right and
-40,-80 is lower left)
track_area stores the size of the bounding rectangle of the
color blob
track_confidence stores the confidence for seeing the blob
cmucamlib Routines (cont.)
• For experts: use trackRaw(…); to specify a particular
color for tracking. Returns 0 if no such blob is found, -1 is
there is a communication error, or the confidence. Also
check out setWin(…);
• More details and low level functions are given in the
comments at the beginning of cmucamlib.ic and
cmucam3.ic in your Handy Board lib folder
Example: cmucamlib-demo.ic
/* demonstrate color blob sensing for poof balls and blue paper */
#use "cmucamlib.ic"
void main()
{
init_camera(); // initialize the camera in YUV mode
clamp_camera_yuv(); //clamp camera white balance in YUV mode
while(!stop_button()) { // hold down Stop for a long time
if (track_blue() > 4) { // you could make this 0 bigger
// number, like 80 for example
printf("blue found:%d\n", track_confidence);
} else
if (track_orange() > 4) {
printf("orange found:%d\n", track_confidence);
} else {
beep();
printf("nothing...\n");
}
} // end while()
} // end main()
cmucamlib Notes
• Don't forget the #use "cmucamlib.ic"
• More details and low level functions are given in
the comments at the beginning of
cmucamlib.ic and cmucam3.ic in your
Handy Board lib folder
Lego RCX
• Simple controller
– Similar memory and processor to Handy Board
• Three sensor inputs
• Three motor ports
–
–
–
–
–
Communicates to your computer via the IR tower
RCX powered by 6 alkaline AA batteries
IR tower powered by 9v alkaline battery
Gray DB9 to DB9 cable connects tower to serial port
Mac Serial port users, use HB cable, the 25-9 pin
connector and then the gray DB9-DB9 cable
RCX
View button: view_button()
or start_button()
(displays sensors port values
if program is NOT running)
Prgm button: prgm_button()
or stop_button()
Power button
turns RCX On and Off
Run Button
runs the main function
Ports 1, 2, & 3 are the
sensor ports
Ports A, B & C are the
motor ports (referred
to in code as A, B &
C (1, 2, & 3 also
work) e.g., fd(A);
or fd(1); turns on
the motor on port A)
Lego RCX Setup
IR Transmitter
Power Supply: 9V battery
RCX
Power Supply: 6 AA batteries
Serial Cable
Download the Firmware
• Make sure your RCX is on and facing the IR tower which is connected
to your personal computer via serial port cable (and USB to serial
adapter if needed). Note: RCX USB IR tower does not work with IC4
• Start IC4
• Select the RCX controller
• Select the appropriate serial port
• Click on connect now
• Click on Download Firmware button if needed
• It is a good idea to put a box over the RCX and IR tower while
downloading to shield the transmission from stray infrared signals that
may be present in the room
• It may even be advisable to put a piece of black tape over the IR end of
the RCX after the download is done!
RCX Sensors
• Touch sensor
• Light and reflectance sensor
• Connect to RCX
with Lego to Lego wire
• Sensors plug into ports 1,2 or 3
RCX Motors
• Black gear motors have built-in
connector and are medium speed
and high torque
• Red & Gray motors use
detachable wire
• Gray motors are high speed and
medium torque
• Red motor is light, low speed
and low torque
• Motors plug into ports A,B or C
Testing your RCX
• Using Lego to Lego wires, attach your Lego touch sensors to
ports 1 and 2
• Attach your light sensor to port 3
• Using Lego to Lego wires, attach motors to ports A, B and C
• Click on IC’s OPEN button
• Load the file RCX/rcxtest.ic located in the IC program folder
• Turn on the RCX and orient it towards the IR tower
• Click on IC’s DOWNLOAD button -- the program will now be
downloaded to the RCX
• After download is complete press the RUN button on the RCX
• Follow the scrolling instructions on the RCX and press the
touch sensors and block, unblock the light sensor -- these
actions cause changes in the motor speeds
Structure
• Common pitfall when trying to increase
mechanical robustness
• The wrong way
Structure
• The right way:
Connector pegs
• Black pegs are tight-fitting for locking
bricks together.
• Grey pegs turn smoothly in bricks for
making a pivot