Some EDURobotics Problems

Technical Robotics Education and Curriculum
1

Hey everyone! I’m having a few problems with the EDURobot, and I was hoping I could get a little help here.

  • Input Values - Our analog inputs read in values from about 10-998, and our digital inputs read 0 or 256. I’m not sure if this is that much of a problem. We’ve been able to work around them when programming. Apparently the analog inputs should be 0-255 and digital inputs 0 or 1. I’m pretty sure I’ve put the right devices in the right pins :D.

  • Banner Sensors (QS18VN6LV) - We learned that the first sensor we worked with was bad (after a week or so :ahh: ), and after getting our second one to work it also went bad. We have a third sensor working, but in summary it’s been a pain. After looking through the manuals for the sensors, we learned that the sensors were not working due to an “output overload” (blinking green light). One sensor blinked when it detected dark, the other blinked only when it detected light. How do we circumvent this error?

Thanks!

The attached pictures are of the EDURobot on 01/09, 01/08, and 01/05.

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edubot010804.jpg
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edubot010504.jpg


edubot010904.jpg
edubot010904.jpg600×542 98.6 KB

edubot010804.jpg
edubot010804.jpg600×532 92 KB

edubot010504.jpg

2

The analog inputs are 10 bits with values from 0-1023.
The digital inputs are 0 & 1

Are you sure you defined the input pins as analog or digital correctly?
The default EDU code for instance defines inputs 1 & 2 as analog inputs and the rest as either digital inputs or outputs. Check in user_routines.c

3

Thanks for the reply!

We’re using an optical sensor to test for input without modifying the Default Code besides the printf statement. We put the sensor in Pin 6 (rc_dig_in06), so with the default configurations it should be okay. It also behaved the same in 8 & 10.

4

Lets try this tack then just to make sure it isn’t a printf issue.
What does your printf look like and how are the variables you use in it declared? Just to make sure you are seeing the correct values.
The printf implementation will give you bad results that look right if you treat it as a normal C printf.
e.g.,

unsigned char digitalvalue;
unsigned int analogvalue;

digitalvalue = (unsigned char) rc_dig_in06;
analogvalue = (unsigned int) Get_Analog_Value(rc_ana_in01);

printf(“My digital value %d, My analog value %d”, (int) digitalvalue, (int)analogvalue);

We wrote our own print functions to get what we want, especially since printf takes up so much space. You can get the same functionality in 40 bytes rather than the 4000 or so printf takes up.

5

Thanks, that did the trick. I’ll remember to do something like that for printf’s. Here were my statements before:

printf("Analog 1 = %d
", Get_Analog_Value(rc_ana_in01));
printf("Digital 6 = %d
", rc_dig_in06);

So now I can see why it didn’t work!

6

I’ve been trying to add the touch sensors from a few years ago (presumably) to my team’s edu bot, but whenever I press in the sensor, the robot either turns off entirely or nothing happens at all. It turns off entirely when I plug it into the +5V and BLK (I’ve tried Digital I/O 1,2,5,6, and 15, and interupts 1,2, and 4), and nothing happens with +5V and SIG.

The code is the default for all other files, and for user_routines.c it is:

/*******************************************************************************

  • FILE NAME: user_routines.c <EDU VERSION>
  • DESCRIPTION:
  • This file contains the default mappings of inputs
  • (like switches, joysticks, and buttons) to outputs on the EDU RC.
  • USAGE:
  • You can either modify this file to fit your needs, or remove it from your
  • project and replace it with a modified copy.

*******************************************************************************/

#include “ifi_aliases.h”
#include “ifi_default.h”
#include “ifi_utilities.h”
#include “user_routines.h”
#include “printf_lib.h”

/*** DEFINE USER VARIABLES AND INITIALIZE THEM HERE **/
/ EXAMPLES: (see MPLAB C18 User’s Guide, p.9 for all types)
unsigned char wheel_revolutions = 0; (can vary from 0 to 255)
unsigned int delay_count = 7; (can vary from 0 to 65,535)
int angle_deviation = 142; (can vary from -32,768 to 32,767)
unsigned long very_big_counter = 0; (can vary from 0 to 4,294,967,295)
*/

//Alex’s additions

//Constants
//Motors
#define LEFT_MOT pwm04
#define RIGHT_MOT pwm03

//Motor Speeds

//Sensors

//Other

//Variables

/*******************************************************************************

  • FUNCTION NAME: Limit_Switch_Max
  • PURPOSE: Sets a PWM value to neutral (127) if it exceeds 127 and the
  •            limit switch is on.
  • CALLED FROM: this file
  • ARGUMENTS:
  • Argument       Type             IO   Description

  • --------       -------------    --   -----------

  • switch_state   unsigned char    I    limit switch state

  • *input_value   pointer           O   points to PWM byte value to be limited
  • RETURNS: void
    *******************************************************************************/
    void Limit_Switch_Max(unsigned char switch_state, unsigned char *input_value)
    {
    if (switch_state == CLOSED)
    {
    if(*input_value > 127)
    *input_value = 127;
    }
    }

/*******************************************************************************

  • FUNCTION NAME: Limit_Switch_Min
  • PURPOSE: Sets a PWM value to neutral (127) if it’s less than 127 and the
  •            limit switch is on.
  • CALLED FROM: this file
  • ARGUMENTS:
  • Argument       Type             IO   Description

  • --------       -------------    --   -----------

  • switch_state   unsigned char    I    limit switch state

  • *input_value   pointer           O   points to PWM byte value to be limited
  • RETURNS: void
    *******************************************************************************/
    void Limit_Switch_Min(unsigned char switch_state, unsigned char *input_value)
    {
    if (switch_state == CLOSED)
    {
    if(*input_value < 127)
    *input_value = 127;
    }
    }

/*******************************************************************************

  • FUNCTION NAME: Limit_Mix

  • PURPOSE: Limits the mixed value for one joystick drive.

  • CALLED FROM: Default_Routine, this file

  • ARGUMENTS:

  • Argument             Type    IO   Description

  • --------             ----    --   -----------

  • intermediate_value    int    I

  • RETURNS: unsigned char
    *******************************************************************************/
    unsigned char Limit_Mix (int intermediate_value)
    {
    static int limited_value;

    if (intermediate_value < 2000)
    {
    limited_value = 2000;
    }
    else if (intermediate_value > 2254)
    {
    limited_value = 2254;
    }
    else
    {
    limited_value = intermediate_value;
    }
    return (unsigned char) (limited_value - 2000);
    }

/*******************************************************************************

  • FUNCTION NAME: Setup_Who_Controls_Pwms
  • PURPOSE: Each parameter specifies what processor will control the pwm.
  • CALLED FROM: User_Initialization
  • Argument             Type    IO   Description

  • --------             ----    --   -----------

  • pwmSpec1              int     I   USER/MASTER (defined in ifi_aliases.h)

  • pwmSpec2              int     I   USER/MASTER

  • pwmSpec3              int     I   USER/MASTER

  • pwmSpec4              int     I   USER/MASTER

  • pwmSpec5              int     I   USER/MASTER

  • pwmSpec6              int     I   USER/MASTER

  • pwmSpec7              int     I   USER/MASTER

  • pwmSpec8              int     I   USER/MASTER
  • RETURNS: void
    ******************************************************************************/
    static void Setup_Who_Controls_Pwms(int pwmSpec1,int pwmSpec2,int pwmSpec3,int pwmSpec4,
    int pwmSpec5,int pwmSpec6,int pwmSpec7,int pwmSpec8)
    {
    txdata.pwm_mask = 0xFF; /     Default to master controlling all PWMs. /
    if (pwmSpec1 == USER) /     If User controls PWM1 then clear bit0. /
    txdata.pwm_mask &= 0xFE; /     same as txdata.pwm_mask = txdata.pwm_mask & 0xFE; /
    if (pwmSpec2 == USER) /     If User controls PWM2 then clear bit1. /
    txdata.pwm_mask &= 0xFD;
    if (pwmSpec3 == USER) /     If User controls PWM3 then clear bit2. /
    txdata.pwm_mask &= 0xFB;
    if (pwmSpec4 == USER) /     If User controls PWM4 then clear bit3. /
    txdata.pwm_mask &= 0xF7;
    if (pwmSpec5 == USER) /     If User controls PWM5 then clear bit4. /
    txdata.pwm_mask &= 0xEF;
    if (pwmSpec6 == USER) /     If User controls PWM6 then clear bit5. /
    txdata.pwm_mask &= 0xDF;
    if (pwmSpec7 == USER) /     If User controls PWM7 then clear bit6. /
    txdata.pwm_mask &= 0xBF;
    if (pwmSpec8 == USER) /     If User controls PWM8 then clear bit7. */
    txdata.pwm_mask &= 0x7F;
    }

/*******************************************************************************

  • FUNCTION NAME: User_Initialization
  • PURPOSE: This routine is called first (and only once) in the Main function.
  •            You may modify and add to this function.

  •            The primary purpose is to set up the DIGITAL IN/OUT - ANALOG IN

  •            pins as analog inputs, digital inputs, and digital outputs.
  • CALLED FROM: main.c
  • ARGUMENTS: none
  • RETURNS: void
    *******************************************************************************/
    void User_Initialization (void)
    {
    rom const char *strptr = “IFI User Processor Initialized …”;

/* FIRST: Set up the pins you want to use as analog INPUTs. /
IO1 = IO2 = INPUT; / Used for analog inputs. /
/
Note: IO1 = IO2 = IO3 = IO4 = INPUT;
is the same as the following:

       IO1 = INPUT;
       IO2 = INPUT;
       IO3 = INPUT;
       IO4 = INPUT;
*/

/* SECOND: Configure the number of analog channels. /
Set_Number_of_Analog_Channels(TWO_ANALOG); / See ifi_aliases.h */

/* THIRD: Set up any extra digital inputs. /
/ The six INTERRUPTS are already digital inputs. /
/ If you need more then set them up here. /
/ IOxx = IOyy = INPUT; /
IO6 = IO8 = IO10 = INPUT; / Used for limit switch inputs. /
IO12 = IO14 = IO16 = INPUT; / Used for limit switch inputs. */

/* FOURTH: Set up the pins you want to use as digital OUTPUTs. /
IO3 = IO4 = OUTPUT;
IO5 = IO7 = IO9 = OUTPUT; / For connecting to adjacent limit switches. /
IO11 = IO13 = IO15 = OUTPUT; / For connecting to adjacent limit switches. */

/* FIFTH: Initialize the values on the digital outputs. */
rc_dig_out03 = rc_dig_out04 = 0;
rc_dig_out05 = rc_dig_out07 = rc_dig_out09 = 0;
rc_dig_out11 = rc_dig_out13 = rc_dig_out15 = 0;

/* SIXTH: Set your initial PWM values. Neutral is 127. */
pwm01 = pwm02 = pwm03 = pwm04 = pwm05 = pwm06 = pwm07 = pwm08 = 127;

/* SEVENTH: Choose which processor will control which PWM outputs. */
Setup_Who_Controls_Pwms(MASTER,MASTER,MASTER,MASTER,MASTER,MASTER,MASTER,MASTER);

/* EIGHTH: Set your PWM output type. Only applies if USER controls PWM 1, 2, 3, or 4. /
/ Choose from these parameters for PWM 1-4 respectively: /
/ IFI_PWM - Standard IFI PWM output generated with Generate_Pwms(…) /
/ USER_CCP - User can use PWM pin as digital I/O or CCP pin. */
Setup_PWM_Output_Type(IFI_PWM,IFI_PWM,IFI_PWM,IFI_PWM);

/*
Example: The following would generate a 40KHz PWM with a 50% duty cycle
on the CCP2 pin (PWM OUT 1):
CCP2CON = 0x3C;
PR2 = 0xF9;
CCPR2L = 0x7F;
T2CON = 0;
T2CONbits.TMR2ON = 1;
Setup_PWM_Output_Type(USER_CCP,IFI_PWM,IFI_PWM,IFI_PWM);
*/

/* Add any other user initialization code here. */

Initialize_Serial_Comms();

Putdata(&txdata); /* DO NOT CHANGE! */

printf("%s
", strptr); /* Optional - Print initialization message. */

User_Proc_Is_Ready(); /* DO NOT CHANGE! - last line of User_Initialization */
}

/*******************************************************************************

  • FUNCTION NAME: Process_Data_From_Master_uP

  • PURPOSE: Executes every 17ms when it gets new data from the master

  •            microprocessor.

  • CALLED FROM: main.c

  • ARGUMENTS: none

  • RETURNS: void
    ******************************************************************************/
    void Process_Data_From_Master_uP(void)
    {
    Getdata(&rxdata); /     Get fresh data from the master microprocessor. */

    Default_Routine(); /* Optional. See below. */

    /* Add your own code here. */

    printf("PWM OUT 7 = %d, PWM OUT 8 = %d
    ",(int)pwm07,(int)pwm08); /* printf EXAMPLE */

    Putdata(&txdata); /* DO NOT CHANGE! */
    }

/*******************************************************************************

  • FUNCTION NAME: Default_Routine
  • PURPOSE: Performs the default mappings of inputs to outputs for the
  •            Robot Controller.
  • CALLED FROM: this file, Process_Data_From_Master_uP routine
  • ARGUMENTS: none
  • RETURNS: void
    ******************************************************************************/
    void Default_Routine(void)
    {
    LEFT_MOT = RIGHT_MOT = 255;
    } /     END Default_Routine(); */

/******************************************************************************/
/******************************************************************************/
/******************************************************************************/

(I originally discovered this with the on/off touch sensor tutorial (code at http://www.rec.ri.cmu.edu/education/edubot/2004_content/prog/stem_3/prog/touch/index.htm#), which is why I had a touch sensor plugged in.)

Anyway, I’d welcome some help.

7

I believe you’re supposed to connect switches to BLK and SIG, the top and bottom pins. The EDU controller has a built in circuit breaker that shuts off power when you connect a switch between +5V and BLK, since it can fry the circuits. Since you didn’t say that you tried attaching the switch to SIG and BLK, I would guess that that is your problem.

8

How would I go about doing that, since SIG and BLK aren’t next to each other? Should I get some wire and try to connect them that way?

9

I would take a PWM cable, cut off the end with the pins, pull apart the wires, get rid of the middle wire, and then attach the switch to the two wires that are left.

10

There is an easier way if you have two wire connectors to the limit switches.
The default EDU code sets up several Digital I/O pins as inputs and adjacent ones as outputs. This is so you can use adjacent signal pins for your limit switches. You can change these definitions in user_routines.c in the User_Initialization function.


  IO6 = IO8 = IO10 = INPUT;      /* Used for limit switch inputs. */
  IO12 = IO14 = IO16 = INPUT;    /* Used for limit switch inputs. */

/* FOURTH: Set up the pins you want to use as digital OUTPUTs. */
  IO3 = IO4 = OUTPUT;
  IO5 = IO7 = IO9 = OUTPUT;     /* For connecting to adjacent limit switches. */
  IO11 = IO13 = IO15 = OUTPUT;  /* For connecting to adjacent limit switches. */

For example, this allows you to connect your limit switch to the two signal pins on Digital I/O 6 and 5. Then you test rc_dig_out06 in your code for an open or closed switch.