Stepper and load cell

I'm now changing the Leonardo to an Uno. Then I will change the driver to a TB6560. Not sure if this will do any good. I'm afraid I have damaged one of them with all my fiddling. 

I'm now changing the Leonardo to an Uno. Then I will change the driver to a TB6560. Not sure if this will do any good. I'm afraid I have damaged one of them with all my fiddling. 

@the-apprentice Changing the Leonardo to a UNO will change nothing. Also changing to the TB6560 is ill advised for a beginner. Stick with either the ULN2003 (good learning board) or the L298N or A4988. Bill has a video/article using all those driver boards, here are the two links VIDEO Article

@zander It was just to make sure the boards are still working correctly. I would need the TB6560 for the end project as the stepper will be drawing about 2 amps.

@the-apprentice Ok, but the venerable old L298N will handle that albeit it will run hot. Also the A4988 will handle 2A. You have choices.

@zander That is something for when I have the program running. If I ever get this to work. LOL

@the-apprentice Just curious, are you following my instructions? It worked for me the first time.

@the-apprentice Black and blue wires on a black background is pointless. I assume you can follow Bills instructions for wiring up a stepper. Add the load cell after the stepper works with a pot, then replace the pot with the load cell.

@zander I have done it separate. Then everything works. The load cell prints to the serial monitor. Not sure how to get the reading to the potentiometer. And the speed to adjust accordingly.

@the-apprentice I think that is two different things. One is using the load cell to control the stepper speed, and the second is to provide either an initial speed and/or a fine tune of the speed when in the main loop. WHICH IS IT?

The following makes no sense. Do you know ohms law?

Not sure how to get the reading to the potentiometer.

This is a serious problem, do you understand why?

The following is a bit of a concern

And the speed to adjust accordingly.

Isn't that the purpose of the load cell code?

Do I need to tell you how to do this again?

@the-apprentice ..Hi, I have been monitoring your post with some interest, so I decided to run your problem through one of the circuit simulators I use for circuit design and troubleshooting. and here's what I came up with:

/*
  Source:  https://www.electroschematics.com/pressure-sensor-guide/ 
*/
#include <HX711.h>
#include <LiquidCrystal_I2C.h>
#include <AccelStepper.h>

const int dirPin = 2;
const int stepPin = 3;
const byte dout_pin = A1;
const byte sck_pin = A0;
unsigned long prevTime = 0;
float motorSpeed = 0;
float sensorReading = 0;

HX711 scale; //  define object called scale
LiquidCrystal_I2C lcd(0x27, 16, 2);

AccelStepper myStepper(AccelStepper::DRIVER, stepPin, dirPin); //define object as myStepper
void setup() {
  Serial.begin(115200);

   pinMode(dirPin, OUTPUT);
   pinMode(stepPin, OUTPUT);
   pinMode(dout_pin, INPUT);
   pinMode(sck_pin, INPUT);

     //digitalWrite(dirPin, HIGH);
     
   lcd.begin(16,2);
   lcd.clear();
   lcd.setCursor(0,0);
   lcd.print("HX711 Demo with");
   lcd.setCursor(0,1);
   lcd.print("HX711 Library");
    delay(1500);
   lcd.clear();
   lcd.setCursor(0,0);
   lcd.print("Initializing");
   lcd.setCursor(0,1);
   lcd.print("the scale");
   delay (1500);
   lcd.clear();

  // parameter "gain" is ommited; the default value 128 is used by the library
  // HX711.DOUT   - pin #A1
  // HX711.PD_SCK - pin #A0

  scale.begin(dout_pin, sck_pin);

  Serial.println("Before setting up the scale:");
  Serial.print("read: \t\t");
  Serial.println(scale.read());                  // print a raw reading from the ADC
  Serial.print("read average: \t\t");
  Serial.println(scale.read_average(20));        // print the average of 20 readings from the ADC
  Serial.print("get value: \t\t");
  Serial.println(scale.get_value(5));            // print the average of 5 readings from the ADC minus the tare weight (not set yet)
  Serial.print("get units: \t\t");
  Serial.println(scale.get_units(5), 1);         // print the average of 5 readings from the ADC minus tare weight (not set) divided

  // by the SCALE parameter (not set yet)
  scale.set_scale(420.f);  //2280.f                     // this value is obtained by calibrating the scale with known weights; see the README for details
  scale.tare();                                  // reset the scale to 0

  Serial.println("After setting up the scale:");
  Serial.print("read: \t\t");
  Serial.println(scale.read());                  // print a raw reading from the ADC
  Serial.print("read average: \t\t");
  Serial.println(scale.read_average(20));        // print the average of 20 readings from the ADC
  Serial.print("get value: \t\t");
  Serial.println(scale.get_value(5));            // print the average of 5 readings from the ADC minus the tare weight, set with tare()
  Serial.print("get units: \t\t");
  Serial.println(scale.get_units(5), 1);         // print the average of 5 readings from the ADC minus tare weight, divided

  // by the SCALE parameter set with set_scale
  Serial.println("Readings:");
}

void loop() {
  
if (millis() >= prevTime+1000){ //read scale every 1 second

 float sensorReading = (scale.get_units());
 Serial.print(sensorReading);
 Serial.print("\t\t");
  prevTime=millis();
 motorSpeed = sensorReading*40; //update motorSpeed

  Serial.println(motorSpeed);
  
}
   
  // set the motor speed:
 
     myStepper.setAcceleration(35);
     myStepper.setMaxSpeed(1000);
     myStepper.setSpeed(motorSpeed);      
     myStepper.runSpeed();
  

  
}

I assume you have followed the instructions on how to wire up everything, as you did say you could get the motor and the loadcell to work separately, but not just together. 

The simulation uses AccelStepper.h library and a A4988 driver with a 5kg load cell., so you will have adjust your calibration constant accordingly, as well as how you define your object for your stepper motor as the struct for this library uses the format 

in your query, you said you wanted the motor to slow down then the pressure ( tension) increased, but I didn't do that in this simulation..I'll just leave that to you to figure out how to do it..lol

Good luck with your project..

regards,

LouisR

@inst-tech Thanks for helping. I will try it again and go back to the first post to read them again.

Posted by: @the-apprentice

↑

@inst-tech Thanks for helping. I will try it again and go back to the first post to read them again.

Your quite welcome.. and please let me know how you progress.. The simulation should be very close to how the motor and loadcell actually work, so I'm somewhat curious as to how it all works out. Good luck, and keep us informed.

regards,

LouisR

@the-apprentice As usual, Pololu has great documentation for the A4988. I HIGHLY recommend you read ALL of it to understand the caveats and rules for using this driver. All drivers have pros and cons and you need to understand them ALL to pick your best match.

Good luck.

@inst-tech I keep getting this error.

Compilation error: no matching function for call to 'HX711::HX711()'