Subject:
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Re: IRPD sensors and LegOS (long)
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Wed, 30 Aug 2000 11:50:49 GMT
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Viewed:
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3387 times
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Since IRPD doesn't use the upper half of the sensor range (above 512), it looks like
it could easily be multiplexed with a touch sensor. Has anyone tried this? (I would
try it myself, but I haven't bought an IRPD [yet!].)
David Chen wrote:
> Well, after much frustration and a great deal of help from the very wise
> Rossz, I was finally able to get up and running w/ DJGPP and LegOS 0.2.4
>
> The first thing I did was write a program to use with Pete Sevcik's IRPD
> proximity detectors that he makes available at www.flash.net/~sevcik
>
> They are a little steep at $29.00 apiece, but you get Left/Front/Right
> proximity detection using just one input port.
>
> I like them so much I bought 2 of em!!! I gotta tell you, LegOS really
> works well with this. I was getting fair results with sending IR Pings
> via the IR Port and using the built in Light Sensors, but this is
> working
> much better.
>
> Here is the code I cobbed together. Note, this program currently keeps
> track of the last 10 turns and distances travelled, but doesn't do
> anything
> with them. Working on a robot that can re-trace it's steps based on
> this
> one. The code's not great, but feel free to play with it.
>
> Dave
>
> /*
> IRPD Rover for LegOS 0.2.4
> 8/27/00
> By David Chen dcchen@pacbell.net
>
> Input 1<=Rotation Sensor
> Input 2<=IRPD Dual Proximity Sensor
> OutputA=>Left Wheel/Drive
> OutputB=>Right Wheel/Drive
>
> IRPD readings as follows, your mileage may very according to your
> battery levels.
> Using the built in macro for Sensor scaling LIGHT_2
>
> No Obstacle = 190 +/- 2
> Obstacle Left = 35 +/- 2
> Obstacle Right = 112 +/- 2
> Obstacle Ahead = 473 +/- 3
> *
> * The contents of this file are subject to the Mozilla Public License
> * Version 1.0 (the "License"); you may not use this file except in
> * compliance with the License. You may obtain a copy of the License at
> * http://www.mozilla.org/MPL/
> *
> * Software distributed under the License is distributed on an "AS IS"
> * basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
> the
> * License for the specific language governing rights and limitations
> * under the License.
> *
> * The Original Code is legOS .lx code, released August 30, 2000.
> *
> * The Initial Developer of the Original Code is David C. Chen.
> *
> */
>
> #include <stdlib.h>
> #include <dsensor.h>
> #include <dmotor.h>
> #include <dlcd.h>
> #include <conio.h>
> #include <unistd.h>
> #include <sys/tm.h>
>
> #define SpeedA 220 /* Adjusts for difference in torques between your */
> #define SpeedC 255 /* A and C motors */
>
> #define TurnTime 680 /* turns for this many msec */
> #define BackupTime 400 /* backs up this many msec */
>
> #define FwdAll {motor_a_dir(fwd); motor_c_dir(fwd);}
> #define RevAll {motor_a_dir(rev); motor_c_dir(rev);}
> #define LeftTurn {motor_a_dir(rev); motor_c_dir(fwd);}
> #define RightTurn {motor_a_dir(fwd); motor_c_dir(rev);}
> #define StopAll {motor_a_dir(brake); motor_c_dir(brake);}
>
> #define MAX_TASKS 10
> #define MAX_VECTORS 10
>
> struct Vector
> {
> char Bearing;
> int Distance;
> };
>
> pid_t pid[MAX_TASKS];
> struct Vector Path[MAX_VECTORS];
>
> int task_index, ODir, Index;
> char Direction;
>
> int StopTask()
> {
> int i;
>
> msleep(200);
> while (getchar()!= KEY_RUN);
> for (i = 0; i < task_index; i++)
> kill(pid[i]);
> ds_passive(&SENSOR_1);
> ds_passive(&SENSOR_2);
> return 0;
> }
>
> void StartTask(int (*code_start)())
> {
> pid[task_index++] = execi(code_start, 0, NULL, 0, DEFAULT_STACK_SIZE);
> }
>
> int ShowStuff()
> {
> while(1)
> {
> if((BATTERY/0x0016)<700) /* Rotation sensor gets flaky if < 7v */
> dlcd_show(LCD_BATTERY_X); /* Show low battery Indicator if < 7v
> */
>
> lcd_int(ROTATION_1); /* Show Rotation count on the LCD */
> cputc_hex_0(Direction); /* Show Current Heading */
> msleep(100);
> }
> }
>
> wakeup_t Obstacle(wakeup_t t) /* Check for IR Proximity detection */
> {
> ODir = LIGHT_2; /* Get a reading */
> return ((ODir < 150) || (ODir > 250)); /* Returns 1 in the event of an
> Obstacle */
> }
>
> int Move()
> {
> motor_a_speed(SpeedA);
> motor_c_speed(SpeedC);
>
> while(1)
> {
> ds_rotation_set(&SENSOR_1,0); /* Clear the Last distance reading */
> FwdAll;
>
> wait_event(&Obstacle,0); /* wait until we detect an obstacle */
>
> StopAll;
> msleep(200);
> RevAll;
> msleep(BackupTime);
>
> Path[Index].Bearing = Direction; /* Record Heading and Distance */
> Path[Index].Distance = ROTATION_1; /* Travelled on this leg */
> (++Index > MAX_VECTORS ? Index = 0 : Index);
>
> if(ODir > 250) /* An object straight ahead */
> { msleep(BackupTime); /* Pick a random direction to turn */
> if(random()&0x01)
> ODir = 30;
> else
> ODir = 120;
> }
>
> if(ODir > 70) /* Obstacle on the Rt */
> { --Direction; /* Left turn subtracts one */
> motor_c_dir(fwd); /* ...so turn to the Left
> */
> }
> else /* But if the obstacle is on Lt */
> { ++Direction; /* Right turn adds one */
> motor_a_dir(fwd); /* ...so turn to the Right */
> }
> msleep(TurnTime); /* For TurnTime msec.
> */
>
> Direction &= 0x07; /* Keep Direction within range 0-7 */
> }
> }
>
> int main()
> {
> task_index = 0;
> StartTask(&StopTask);
>
> srandom(sys_time); /* Set a Random Number Seed */
>
> ds_active(&SENSOR_2); /* Power the IRDP Sensor on Port 2 */
>
> ds_active(&SENSOR_1); /* Power up Rotation Sensor Port 1 */
> ds_rotation_on(&SENSOR_1); /* Initialize sensor */
>
> msleep(1000);
>
> Index = 0; /* Initialize index to Path array */
> Direction = 0; /* Call starting direction 0, increasing */
> /* as you go clockwise by 1 / 45 degrees */
> StartTask(&ShowStuff);
> StartTask(&Move); /* Go! */
>
> tm_start();
>
> return(0);
> }
>
> --
>
> dcchen@pacbell.net
--
___________________
$50,000 reward for Jill Behrman:
<http://www.indiana.edu/~alumni/iuaa/jillbehrman>
Suppose one of you has a hundred sheep and
loses one of them. Does he not leave the
ninety-nine in the open country and go
after the lost sheep until he finds it?
---Luke 15:4. The Holy Bible (NIV)
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Message is in Reply To:
 | | IRPD sensors and LegOS (long)
|
| Well, after much frustration and a great deal of help from the very wise Rossz, I was finally able to get up and running w/ DJGPP and LegOS 0.2.4 The first thing I did was write a program to use with Pete Sevcik's IRPD proximity detectors that he (...) (26 years ago, 30-Aug-00, to lugnet.robotics.rcx.legos)
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