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Topic: 2 servos (or any functions) operating simultaneously? (Read 14490 times) previous topic - next topic

PaulS

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I think I'm heading in the right direction and what I now understand or at least think I understand is that there is a conversion problem.

But, I'm not going to show you my code.

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It is between the 'serial buffer' and the 'readString' variable which is then indexed to 'n' in 'servo.write()'.

Well, certainly. Fix it. Or not. Only you can see what you are talking about.

Quote
I'm still looking for applicable information on this subject. 

What subject would that be?

evolion

PaulS:

So are your comments serious?
                                       ...joking?
                                 or seriously joking?

the code I've been working on is on post #27
       are you saying you aren't going to post yours?

Well, if you look at post #27, you can see it too
if you were to run it, you can certainly see what it do
Unfixed. And so.

the subject is apparently in the form of a question as the title of the thread (see title)
      any more explanation of my problem would be ad nauseam

If you have any info that could possibly help me solve it, I'd love to know about it. 

AWOL

Quote
the code I've been working on is on post #27
       are you saying you aren't going to post yours?

If you've been working on the code in post #27, presumably it now doesn't look like the code in post #27, so you need to post it again.
Now.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

zoomkat

Quote
the subject is apparently in the form of a question as the title of the thread (see title)
      any more explanation of my problem would be ad nauseam


Well, "2 servos (or any functions) operating simultaneously?" seems to have you stummped. The code only does one thing at a time, but the code itself performs actions so fast you will not be able to detect the individual actions (unless you add delays and such).

Quote
If you have any info that could possibly help me solve it, I'd love to know about it. 


Well, if the "it" problem is a knowledge deficit on your part, it is up to you to get up to speed.
Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

evolion

#34
Jan 26, 2013, 04:51 am Last Edit: Jan 26, 2013, 09:41 am by evolion Reason: 1
AWOL:
I have probably made 100's of changes to the code in #27 by now, except none of them have have brought me any closer to my goal.  Each change has had either no effect, produces undesirable effects, nullifies the code altogether, or doesn't compile.  
I believe each half of the code (PROGMEM with table to Serial buffer) and (Serial.read to index. to .write) are doing things I want to see happen, I just can't seem to integrate them to work together.  Nothing I have done has furthered what is already there.
So, effectively, the code remains unchanged.
 
zoomkat:
I understand that it does one thing at a time and gives the impression of simultaneity, the code you presented to me (2nd half of the code in #27) definitely produces this effect.  I'm still trying to figure out what function/s will replace manually inputting parameters to serial.  

The "it" certainly results from my surplus of ignorance but I'm not sitting idle waiting for someone to bestow their esoteric knowledge unto me, although it would be sweet to be blessed with such an occurrence, not unlike you supplying much the code I'm working with now.  I'm doing my due diligence and have gone through the entire reference especially focused on 'string theory', investigated many of the links provided and their links also, as well as other forums and books.  I'm learning as much as I can as quickly as I can - I may have totally overlooked the exact solution because I didn't know what I was looking at, I don't know.
I'm not going to give up on the issue, I want to understand how it is done, but I'm reaching a threshold of having to re-prioritize in order to meet the deadline for the robotics challenge.  I've figured out a way for a hexapod to use 2 servos to do the work of the 12 originally planned and as long as I am able to get the parts printed it shouldn't be too difficult to make happen.  I won't need to have the servos operate simultaneously.  

I will continue to work on this simultaneous servo problem in my spare time.  In the meantime I built a different style of 'walking' robot prototype using 2 servos out of battery compartments and paperclips.  I've got a couple of other projects that I want to finish/get started after the challenge.  I'll go nuts if I only focus on this problem.

[img][img]

zoomkat

There are lots of three servo hexipods, and other simple walking bots. Below are some ideas.

http://www.google.com/search?num=100&hl=en&lr=&tbo=d&as_qdr=all&spell=1&q=three+servo+hexapod&sa=X&ei=DVYDUdKGAcbo0gGWlYFQ&ved=0CC8QBSgA&biw=1173&bih=642

http://davidbuckley.net/DB/Inspire.htm

Google forum search: Use Google Advanced Search and use Http://forum.arduino.cc/index in the "site or domain:" box.

evolion

#36
Jan 26, 2013, 09:05 am Last Edit: Jan 28, 2013, 07:06 am by evolion Reason: 1
Ha Ha, she's one hot bot.

I thought I'd post my first project.  
I don't have much to offer the forum yet, but maybe someone can benefit from this.
I built this robot out of roof flashing, designed to stay on top of fine loose sand,  spike-paddles were cut into each wheel and a 'ski' was on a pivot in the rear
I wish I had a pic of it finished

here's the code I used with it:
  ~this has nothing to do with my hexapod idea
Code: [Select]
/* 10-5-10
 Pete Dokter
 SparkFun Electronics

This is an example sketch for Arduino that shows very basically how to control an Ardumoto
motor driver shield with a 5V Arduino controller board.

~~~ The variable values in this code have changed significantly from the (above) author's draft,
   I also incorporated bumper sensors (whiskers) with iterations and fixed the northward navigation
  */
#include <Wire.h>  
#include <LSM303.h>  //compass/accelerometer
LSM303 compass;

int pwm_a = 3;   //PWM control for motor outputs 1 and 2 is pin 3
int pwm_b = 11;  //                               outputs 3 and 4 is pin 11
int dir_a = 12;  //direction control for motor outputs 1 and 2 is pin 12
int dir_b = 13;  //                                      outputs 3 and 4 is pin 13

const int bumperPinR = 2;   //bumper pins
const int bumperPinL = 4;  

int bumperStateR = 0;      //variable for reading the bumper status
int bumperStateL = 0;    

int IRsensorPin = A0;     //input pin for IR sensor
int IRsensorValue = 0;    //variable to store value of IR sensor

int LEDPin = 13;          //On when backing up

void setup()
{
  Serial.begin(9600);
 pinMode(pwm_a, OUTPUT);   //Set control pins to be outputs (motors)
 pinMode(pwm_b, OUTPUT);
 pinMode(dir_a, OUTPUT);
 pinMode(dir_b, OUTPUT);

 //initialize bumper and IR pins
 pinMode(bumperPinR, INPUT);
 pinMode(bumperPinL, INPUT);
 pinMode(IRsensorPin, INPUT);

 pinMode(LEDPin, OUTPUT);

 digitalWrite(dir_a, LOW);    //Set motor direction, 1 low, 2 high
 digitalWrite(dir_b, LOW);    //Set motor direction, 3 high, 4 low
 analogWrite(pwm_a, 255);     //set both motors to 100% duty cycle
 analogWrite(pwm_b, 255);

 Wire.begin();            
 compass.init();
 compass.enableDefault();
 //Use Calibrate example program for compass values
            //(environment specific ~magnetics differ from place to place, recalibrate)  
    //M min X: -405 Y: -108 Z: -9 M max X: -382 Y: -86 Z:8
                  //values are copied from serial monitor, pause calibration to copy  
  compass.m_min.x = -405;
  compass.m_min.y = -108;
  compass.m_min.z = -9;
  compass.m_max.x = -382;
  compass.m_max.y = -86;
  compass.m_max.z = +8;
}
void loop()
{
   digitalWrite(LEDPin, LOW);
 digitalWrite(dir_a, LOW);   //motor direction, 1 low, 2 high (forward)
 digitalWrite(dir_b, LOW);   //                      3 high, 4 low

 analogWrite(pwm_a, 200);    //motors run at 80% duty cycle (slower)
 analogWrite(pwm_b, 200);
   
compass.read();
int heading = compass.heading((LSM303::vector) {1,0,0} );   //1,0,0 aligns North
   Serial.println("");
   Serial.print("Compass: ");
   Serial.print(heading);
   Serial.print("\t");

//IR reading
 IRsensorValue = analogRead(IRsensorPin);    
   Serial.print("IR Reading: ");
   Serial.print(IRsensorValue);
   Serial.print("\t");

//read state of bumper value
 bumperStateR = digitalRead(bumperPinR);
 bumperStateL = digitalRead(bumperPinL);

//Check IR Sensor
  if(IRsensorValue > 455)
   {
       Serial.println("");
       Serial.println("IR rev ");
 //reverse
    digitalWrite(dir_a, HIGH);  //motor direction, 1 low, 2 high
    digitalWrite(dir_b, HIGH);  //                     3 high, 4 low

    analogWrite(pwm_a, 225);    //motors run slower than 100% duty cycle =(255)
    analogWrite(pwm_b, 225);
     delay(450);

 //turn right
    digitalWrite(dir_a, HIGH);  //motor direction, 1 low, 2 high
    digitalWrite(dir_b, HIGH);  //                      3 high, 4 low

    analogWrite(pwm_a, 15);     //turns left in reverse
    analogWrite(pwm_b, 245);    //points further right in forward direction
     delay(520);
     
 //forward
    digitalWrite(dir_a, LOW);   //motor dir, 1 low, 2 high
    digitalWrite(dir_b, LOW);   //            3 high, 4 low

    analogWrite(pwm_a, 230);    //motors run at ()% duty cycle
    analogWrite(pwm_b, 230);
     delay(850);
   }
else
 {  
//check if bumper triggered
 if (bumperStateR == LOW)
  {    
     //back and turn L    
        Serial.println("");
        Serial.println("bumperR rev ");
  //reverse
    digitalWrite(dir_a, HIGH);  //motor dir, 1 low, 2 high
    digitalWrite(dir_b, HIGH);  //            3 high, 4 low

    analogWrite(pwm_a, 225);    //motors run slower than 100% duty cycle
    analogWrite(pwm_b, 225);
     delay(450);

  //turn left
    digitalWrite(dir_a, HIGH);  //motor dir, 1 low, 2 high
    digitalWrite(dir_b, HIGH);  //             3 high, 4 low

    analogWrite(pwm_a, 15);     //turns left in reverse
    analogWrite(pwm_b, 245);    //points further right in forward direction)
     delay(525);
     
  //forward
    digitalWrite(dir_a, LOW);   // 1 low, 2 high
    digitalWrite(dir_b, LOW);   // 3 high, 4 low

    analogWrite(pwm_a, 230);    //motors run at ()% duty cycle
    analogWrite(pwm_b, 230);
     delay(880);
   }
 if (bumperStateL == LOW)
  {    
     //back and turn R    
        Serial.println("");
        Serial.println("bumper L rev ");
  //reverse
    digitalWrite(dir_a, HIGH);   //1 low, 2 high
    digitalWrite(dir_b, HIGH);   //3 high, 4 low

    analogWrite(pwm_a, 225);     //motors slower than 100% duty cycle
    analogWrite(pwm_b, 225);
     delay(450);

  //turn right
    digitalWrite(dir_a, HIGH);   //1 low, 2 high
    digitalWrite(dir_b, HIGH);   //3 high, 4 low

    analogWrite(pwm_a, 245);     //turns left in reverse
    analogWrite(pwm_b, 15);      //points further right in forward direction)
     delay(525);
     
  //forward
    digitalWrite(dir_a, LOW);    //1 low, 2 high
    digitalWrite(dir_b, LOW);    //3 high, 4 low

    analogWrite(pwm_a, 230);     //motors at ()% duty cycle
    analogWrite(pwm_b, 230);
     delay(880);
   }  
//break out of iteration, start navigation
  else
   {
    if(heading < 255)     // (270) = north
     {
      //turn left
        Serial.print("left");
      digitalWrite(dir_a, LOW);   //1 low, 2 high
      digitalWrite(dir_b, LOW);   //3 high, 4 low

      analogWrite(pwm_a, 135);    //motor A (left) slower, B (right) faster
      analogWrite(pwm_b, 225);
       delay(40);
     }

    if(heading > 285)
     {
      //turn right
        Serial.print("right");
      digitalWrite(dir_a, LOW);   //1 l, 2 h
      digitalWrite(dir_b, LOW);   //3 h, 4 l

      analogWrite(pwm_a, 225);    //motor A faster, B slower
      analogWrite(pwm_b, 135);
       delay(40);
     }
   }
 }  
}


  How do I attach a normal size photo?

evolion

Ok, so I found a new approach to my problem.  I'm a bit more hopeful but I can't get it to compile. 

Here is what I found (the list of compiler errors is huge):
Code: [Select]
//(this sketch is straight from the playground)
// test sketch for MegaServo library
// this will sweep all servos back and forth once, then position according to voltage on potPin

#include <MegaServo.h>

#define FIRST_SERVO_PIN  22 

MegaServo Servos[MAX_SERVOS] ; // max servos is 32 for mega, 8 for other boards

int pos = 0;      // variable to store the servo position
int potPin = 0;   // connect a pot to this pin.

void setup()
{
  for( int i =0; i < MAX_SERVOS; i++)
    Servos[i].attach( FIRST_SERVO_PIN +i, 800, 2200);

  sweep(0,180,2); // sweep once   
}

void sweep(int min, int max, int step)
{
  for(pos = min; pos < max; pos += step)  // goes from 0 degrees to 180 degrees   
  {                                  // in steps of 1 degree
    for( int i =0; i < MAX_SERVOS; i++){
      Servos[i].write( pos);     // tell servo to go to position 
    }
    delay(15);                  // waits 15ms for the servo to move
  }
  for(pos = max; pos>=min; pos-=step)     // goes from 180 degrees to 0 degrees
  {                               
    for( int i =0; i < MAX_SERVOS; i++){
      Servos[i].write( pos);     // tell servo to go to position 
    }
    delay(15);                  // waits 15ms for the servo to move
  }   
}

void loop()
{
  pos = analogRead(potPin);   // read a value from 0 to 1023
  for( int i =0; i < MAX_SERVOS; i++)
    Servos[i].write( map(pos, 0,1023,0,180));   
  delay(15);   
}


I compared the above sketch to others I found (sorry they aren't cited, I didn't record where the other similar examples were from) and here are the changes I made:
Code: [Select]
#include <MegaServo.h>
#include <Wire.h>
#include <arduino.h>

#define NBR_SERVOS 12
#define FIRST_SERVO_PIN  2 
  MegaServo Servos[NBR_SERVOS] ; // max servos is 12
   MegaServo MegaServo;
int pos = 0;      // variable to store the servo position
int potPin = 0;   // connect a pot to this pin.
 
void setup()
{
   Serial.begin(9600);
  MegaServo.writeMicroseconds(1500);
  int i = 0;
  pinMode(i,OUTPUT);
}

void Servos digitalWrite.MegaServo( )
{
  for( int i =0; i < NBR_SERVOS; i++)
    Servos[i].attach( FIRST_SERVO_PIN +i, 800, 2200);

  sweep(0,180,2); // sweep once   
}

void sweep(int min, int max, int step)
{
  for(pos = min; pos < max; pos += step)  // goes from 0 degrees to 180 degrees   
  {                                  // in steps of 1 degree
    for( int i =0; i < NBR_SERVOS; i++){
      Servos[i].write( pos);     // tell servo to go to position 
    }
    delay(15);                  // waits 15ms for the servo to move
  }
  for(pos = max; pos>=min; pos-=step)     // goes from 180 degrees to 0 degrees
  {                               
    for( int i =0; i < NBR_SERVOS; i++){
      Servos[i].write( pos);     // tell servo to go to position 
    }
    delay(15);                  // waits 15ms for the servo to move
  }   
}

void loop()
{
  pos = analogRead(potPin);   // read a value from 0 to 1023
  for( int i =0; i < NBR_SERVOS; i++)
    Servos[i].write( map(pos, 0,1023,0,180));   
  delay(15);   
}

compiler error:  MegaServo:23: error: expected initializer before 'digitalWrite'

This is the only error that this version produces.  I don't know that it's necessarily a good thing or not.  I guess I don't understand what an 'expected initializer' is, even after some research on it.  If this does end up compiling, I don't know that it will work correctly as I don't understand most of what is going on in it.  Please don't ask me WHY I made some of the changes were made in it as I don't really remember and probably couldn't tell you in the first place.  All I know is that this is the closest it has come to compiling.

Thanx for any input on this

AWOL

Code: [Select]
void Servos digitalWrite.MegaServo( ) what's that?
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

PaulS

Code: [Select]
   MegaServo MegaServo;
Having an instance name the same as the class name is not the brightest idea I've seen today.

evolion

#40
Feb 08, 2013, 09:30 am Last Edit: Feb 08, 2013, 10:28 am by evolion Reason: 1
AWOL:  
If I knew, I could tell you.  
At some point I had tried some random switching of terms, that's probably what that is a result of.
Correct me if I'm wrong.  Your comment would imply that you can easily see or even know for certain that something is not right with that particular line of code.  I'm fairly sure that's not the only error but if you would care to expand on your comment a bit and share some of the wisdom I am not privy to, I would more than appreciate being exposed to what you know about it. 

PaulS:
I was thinking the same thing when I saw something similar in another code but figured I would give it a shot anyway.
While we are on the subject of luminescence, would you like to shed some light on why the idea is so dim?  Maybe explain the conflict or possible conflicts?  Can instance and class written structures be/look exactly the same?  Could you suggest how it be done differently?  What would you do in such a case?  Does this even need to be done at all?


What I do know is that there is only one compiler error in the revision - an enormous improvement from the original in the playground where it is stated (in sum):  just copy and paste, no changes necessary.  I don't know who's smoking more of what on the playground but as you can see it clearly was not that simple.  Unless of course there is some obvious step omitted that every programmer knows to be common knowledge while overlooking the inexperienced newbie who's yet to be a programmer.  

AWOL

Could you post a link to the Playground page where you found that please?
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

evolion


AWOL

#43
Feb 08, 2013, 10:50 am Last Edit: Feb 08, 2013, 01:39 pm by AWOL Reason: 1
Quote
Your comment would imply that you can easily see or even know for certain that something is not right with that particular line of code.  

It isn't even like saying "My hovercraft is full of eels", a sentence that follows the rules of English syntax, but which makes very little sense.

Code: [Select]
void Servos digitalWrite.MegaServo( )
Here, we have the implication that we're looking at a function definition which doesn't return anything.
After that, my brain refuses to recognise what is going on.
I almost see a class name ("Servo"), a function name I recognise ("digitalWrite"), but with a structure field name ("MegaServo") I don't.

It's a bit like a Dali painting, expressed in C.

Afterthought Edit: In contrast, Duff's Device is more like an M.C. Escher print
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

JimboZA

Quote
"My hovercraft is full of eels", a sentence that follows the rules of English syntax, but which makes very little sense.



.....not true... makes perfect sense to Hungarians in tobacconists.
"Could you do the egg bacon spam and sausage without the spam then? "

No PMs for help please.
DO NOT power servos from Arduino 5V: give them their own power and connect the grounds.

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