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Author Topic: Increase Stepper Motor Speed  (Read 8762 times)
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Pittsburgh, PA, USA
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Is the pot output connected to A0, maybe through a 1K resistor? And in that connect, a 10k or so resistor to ground as well? If you don't have that resistor to ground then you will always get saturated reads and wonder what's wrong.

Then analog read A0 and you have your turn pot sensed.

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I find it harder to express logic in English than in Code.
Sometimes an example says more than many times as many words.

florida
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the delay got mad and said it expected a ; . maybe its the pot i have one wire to a ground middle wire to the a0 pin one wire to a 5 volt spot the green light lights up when i move it one way
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All statements in C need to end in a semicolon ;
What is the green light? Is it the direction?
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the delay got mad and said it expected a ; . maybe its the pot i have one wire to a ground middle wire to the a0 pin one wire to a 5 volt spot the green light lights up when i move it one way

You want to attach to the middle wire, another wire with 10+k resistor to ground.

You want some resistors in there to limit current flow. One pin can handle 40 mA but you don't want to push the pins like that, 20 mA per pin is a nice 'limit' but you don't need that much current.
I have input pins being fed 0 - 5V through 2.2k resistors, 2.27 mA, works fine. Those same input pins connect to ground through 22k resistors, that's where the 2.27 mA goes. Maybe I should try 4.7k instead of 2.2k to use 1.06 mA.

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Sometimes an example says more than many times as many words.

florida
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ok i am back on this project life and frustration got in the way. now i am ready to try again. i also need to start from the point of what resistors do i need to install for the pot to work. i would like to have the pot control a stepper motor to move 200 steps forward and 200 backward. if pot stops so does the motor. thanks for helping everyone
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OK so, as it has been a time and there has been several software versions used, can you post a schematic of what you have wired up along with the code you are trying to use.
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florida
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been busy thanks for patients in advance i am using the simple program from before a polou a4988 driver and a 3 prong pot from radio shack  i just bought a volt meter my power supply has an output of 24v and 6.5a i have the driver in the easiest setting with 1a and 2a connected and 1b and 2b connected no microstepping.i just need the motor to follow what the pot does 200 steps one way 200 steps the other
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OK so, as it has been a time and there has been several software versions used, can you post a schematic of what you have wired up along with the code you are trying to use.
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florida
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i attached a quick pencil sketch if it comes out to small i will make a bigger one. i hope someone can help i feel it is so simple to make this work but i just dont get it


* stepper sketc.jpg (25.22 KB, 320x240 - viewed 41 times.)
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florida
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maybe we can try this code again

// change this to the number of steps on your motor
#define dirPin 10
#define stepPin 11

// the previous reading from the analog input
int previous = 0;
int val =0;
int dir = 0; // direction of movement
int steps = 0; // number of steps to take

void setup()
{
  pinMode(stepPin, OUTPUT);
 digitalWrite(stepPin, LOW);
 pinMode(dirPin, OUTPUT);
}

void loop()
{
  // get the sensor value
   val = analogRead(0);

  // move a number of steps equal to the change in the
  // sensor reading
   steps = (val - previous);
  if(steps > 0){
    dir = 0;
  }
  else {
    dir = 1;
    steps = -steps;
  }
  digitalWrite(dirPin, dir); // set up the direction
  for(int i = 0; i< steps; i++){
    digitalWrite(stepPin, HIGH); // pulse the step pin
    digitalWrite(stepPin, LOW);
  }
  // remember the previous value of the sensor
  previous = val;
}
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Between these two lines:

Code:
digitalWrite(stepPin, HIGH); // pulse the step pin
    digitalWrite(stepPin, LOW);

add the delay:

Code:
digitalWrite(stepPin, HIGH); // pulse the step pin
delay(100);
    digitalWrite(stepPin, LOW);

You will probably be able to use lower #s than 100...
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Quote
i attached a quick pencil sketch
But it is not a schematic is it, it does not show the circuit you are using.
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florida
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im not sure what you are talking about do you want a picture of the way i have it set up?
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Quote
do you want a picture of the way i have it set up?
No I want a schematic.
http://blog.makezine.com/archive/2011/01/reading-circuit-diagrams.html
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florida
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is this right? and thanks for helping. it means alot


* schematic2.jpg (45.56 KB, 432x237 - viewed 31 times.)
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