Load sensing

I have to sense the compression and tension force in a cylinder rod and im going to use strain gauges and hx 711 amplifier. So my question is how Im going to approach this and how to do the calibration specifically shunt calibration
And can i use the load cell code in the above question in order to get the force values.
Can someone help me with these problems because im facing a lot of issues

Ehte:
So my question is how Im going to approach this

There are plenty of tutorials online on how to use load cells.

Ehte:
And can i use the load cell code in the above question in order to get the force values.

What code?

Ehte:
Can someone help me with these problems because im facing a lot of issues

Describe what you did until now and what's wrong exactly

Hi,
Welcome to the forum.

Please read the first post in any forum entitled how to use this forum.
http://forum.arduino.cc/index.php/topic,148850.0.html .

What is your electronics, programming, arduino, hardware experience?
What model Arduino are you using?

Thanks.. Tom... :slight_smile:

You need the right strain gauges for measuring both compression and tension. One gauge only can measure tension, in only one direction. That's why strain gauges usually come split into multiple gauges. A gauge pair can be used for one half of a bridge, with resistors of the same (unstressed) resistance. Triple gauges allow to measure linear tension and rotational torque. Load cell code can be useful for setup, calibration and data transfer and timing, the remaining calculations must be adopted to the strain gauge type.

I'm not sure whether compression can be measured by strain gauges at all. Some initial stress or load may be required while the gauge is mounted, so that some stress remains when the load is removed. But you may not want to mount strain gauges yourself, that's a profession of its own. Imagine what you will measure when the glued gauge starts creeping on the surface...

This is my code for strain gauges which i connected in a wheat stone bridge configuration and i didn't use any load cell because it is based on a strain gauge wheat stone bridge configuration

#include "HX711.h"

#define DOUT 3
#define CLK 2

HX711 scale(DOUT, CLK);

float calibration_factor = -96650;

void setup() {
Serial.begin(9600);
Serial.println("Press T to tare");
scale.set_scale(-96650); //Calibration Factor obtained from first sketch
scale.tare(); //Reset the scale to 0
}

void loop() {
Serial.print("Weight: ");
Serial.print(scale.get_units(), 3);
Serial.println(" kg");

if(Serial.available())
{
char temp = Serial.read();
if(temp == 't' || temp == 'T')
scale.tare(); //Reset the scale to zero
}
}

My problem is that I'm not getting the force values is there any problem with this code

DrDiettrich:
I'm not sure whether compression can be measured by strain gauges at all.

Yes, just as well as tension.
Using two complementary gauges however eliminates errors due to the temperature coefficient for the most part and also doubles the resolution.

So can i use four strain gauges in a wheat stone bridge and if i do use this setup can I use the above code that i mentioned earlier

In a full bridge you use two sensors for temperature compensation, and two resistors that make the bridge balanced in unstressed state.

couka:
Yes, just as well as tension.
Using two complementary gauges however eliminates errors due to the temperature coefficient for the most part and also doubles the resolution.

So can i use four strain gauges in a wheat stone bridge and if i do use this setup can I use the above code that i mentioned earlier