Week 7 RCX math
The RCX does not follow the traditional rule Please Excuse My Dear Aunt Sally.
Example: Parenthesis, Exponents, Multiplication, Division Addition And Subtraction.
The following program drove The line follower shooter bot.
/* shooter_linefollower_bot.nqc
Written by Professor Mohamad Hassoun, February 2001 (Last modified October 04)
Single Light Sensor based black line tracking robot (search for line capability)
with side IR-based object detection. Missile firing at detected object.
IT IS IMPORTANT THAT THE TRACK LIGHT THRESHOLD BE PLACED ON THE
BLACK TRACK
INITIALLY JUST BEFORE THE PROGRAM IS RUN. THIS ALLOWS THE ROBOT
TO SET THE
PROPPER TRACK THRESHOLD UNDER ANY ROOM LIGHT BACKGROUND.
Program uses one light sensor, one IR sensor, and one touch sensor.
It drives 3 motors */
#define EYE_1
#define EYE_2
#define BUMP
#define LEFT
#define RIGHT
#define CENTER
SENSOR_1
SENSOR_2
SENSOR_3
OUT_A
OUT_C
OUT_B
#define TURN_SPEED
#define INITIAL_TIME
4
3
int direction, time, LINE_THRESHOLD;
int x, OBSTACKLE_DETECTION_THRESHOLD;
task main()
/* The following part sets the light sensors thresholds based on room
light condition and tracks (black line) light reflection. It also
starts all tasks including line tracking */
{
SetSensor(EYE_1, SENSOR_LIGHT);
SetSensor(EYE_2, SENSOR_LIGHT);
SetSensor(BUMP, SENSOR_TOUCH);
RCX how to read the sensor.
// IR sensor
// light sensor
// Touch sensor
OBSTACKLE_DETECTION_THRESHOLD = 40;
RCX how to detect an obstacle
Tells the
Tells the
// The following part sets the threshold based on room light condition
x = EYE_2;
LINE_THRESHOLD = x + 5;
help control RCX reaction
start shooter;
start bumper;
start follow_line;
to start the defined task
}
Add 5 to
Tells the RCX
task follow_line()
// Follow black tarck
{
// initialize the variables
direction = 1;
time = INITIAL_TIME;
// start driving
OnFwd(LEFT+RIGHT);
Moves robot
while(true)
{
// read the sensor value
if (EYE_2 < LINE_THRESHOLD)
Monitors the sensor and this
condition must be met.
{
// we are over the line; do nothing.
}
else
{
// need to find the line again
ClearTimer(0);
if (direction == 1)
{
SetPower(RIGHT+LEFT, TURN_SPEED);
Rev(LEFT);
}
else
{
SetPower(RIGHT+LEFT, TURN_SPEED);
Rev(RIGHT);
}
while(true)
loop in Task follow line
Second infinite
{
// have we found the line?
if (EYE_2 < LINE_THRESHOLD)
{
time = INITIAL_TIME;
break;
interrupts
infinite loop;
}
if (Timer(0) > time)
{
// try the other direction
direction = direction*(-1);
time *= 2;
doubles time
break;
To stop inner infinite loop
}
}
SetPower(RIGHT+LEFT, OUT_FULL);
Fwd(RIGHT+LEFT);
}
}
}
task shooter()
/* If IR sensor detects a dark object, the robot shoots it. An active reading
scheme using two IR sensors is employed in order to eliminate ambiant light
effects. */
{
while(true)
{
if (EYE_1 > OBSTACKLE_DETECTION_THRESHOLD)
{
Off(RIGHT+LEFT);
PlaySound(SOUND_FAST_UP);
OnFwd(CENTER);
Wait(10);
OnRev(CENTER);
Wait(13);
Off(CENTER);
OnFwd(RIGHT+LEFT);
}
}
}
/* The following task makes the robot backup briefly and then attempt a 180
degrees turn. This way, the robut ends up tracking the black line in the
opposite direction. */
task bumper()
{
while(true)
Infinite loop: helps
the program run continuously checking sensors
{
if(BUMP == 1) // Bumper activated if sensor 3 reads 1
{
stop follow_line;
stop shooter;
These stops are here to help
the robot execute task smoothly without any confusion
OnRev(RIGHT+LEFT);
Wait(50);
OnFwd(RIGHT);
Wait(175);
OnFwd(RIGHT+LEFT);
turn @ 180 Degrees
start follow_line;
start shooter;
resume tasks
Helps the robot
Helps robot
}
}
}
We also learned about the different mathematical capabilitiesof the RCX. The RCX is
unable to display numbers that extend outside of the domain. This means there are limits
and if the calculations do not fall within the specified range the numerical result will be
incorrect.
//tarek_sorter.nqc Program to sort red and silver ping-pong balls.
//Must have a red as first ball in feeder at start.
//September, 2004 Prof. M. Hassoun
int red_ball, no_ball;
task main ()
{
SetSensor (SENSOR_1, SENSOR_LIGHT);
SetSensor (SENSOR_2, SENSOR_TOUCH);
SetSensor (SENSOR_3, SENSOR_TOUCH);
ClearTimer (0);
A timer is used to stop the program after 500 seconds= 50000
no_ball = 30;
Wait(75);
if (SENSOR_2 != 1)
{
OnRev(OUT_A + OUT_C);
until(SENSOR_2 == 1);
Off(OUT_A + OUT_C);
calibration for the arm( the part that drops the balls)
}
Wait(75);
red_ball = SENSOR_1 - 12; // color calibration
12 to allow a range for the infrared light
drop_ball();
while(true)
{
sort();
if(Timer(0) > 5000)
{
Off(OUT_A+OUT_B+OUT_C); This is the main infinite loop
break;
the infinite loop.
}
}
}
This is the initial
Subtract
This breaks from
void sort()
The sort
command enables the machine to activate the sensors and separate the ball
{
until(SENSOR_1 >= no_ball);
The program
will stop here if the sensor does not collect a ball reading
Wait(100);
if(SENSOR_1 >= red_ball)
{
PlaySound (SOUND_UP);
if (SENSOR_2 != 1)
{
OnFwd(OUT_A + OUT_C);
Wait(15);
OnRev(OUT_A + OUT_C);
until(SENSOR_2 == 1);
Off(OUT_A + OUT_C);
}
Wait(50);
drop_ball();
}
Wait(75);
if(SENSOR_1 < red_ball && SENSOR_1 > no_ball)
Sets calibration for silver ball
{
PlaySound (SOUND_DOWN);
if (SENSOR_3 != 1)
Sensor #3 is the one that controls the arm.
{
OnRev(OUT_A + OUT_C);
Wait(15);
OnFwd(OUT_A + OUT_C);
until(SENSOR_3 == 1);
Off(OUT_A + OUT_C);
}
Wait(50);
drop_ball();
}
Wait(75);
}
void drop_ball()
{
OnRev(OUT_B);
Wait(60);
Float(OUT_B);
allows the arm to return to hold the balls in place
}
This command
The above program was used to run this project.
This is the Ball Sorter Bot.
The problem solving process
Designing- Builder must understand the specifications of the objectives and the
constraints. Be knowledgeable of the project goal.
BuildingAnalyzing & refining