Voltage reading fluctuate in the Arduino although the Torque does not changes

Projects Discussion and Showcase Science and Measurement
#1

Dear there,
I am working on torque measuring in Arduino UNO. The torque sensor produce voltage which is amplified by strain gage and read in the Arduino platform. The problem is that in no load condition the voltage reading is 0.145 V which changes 0.156 V although no load applied to the torque. Since this unusual changing can hamper my torque data and significant error displays. Could anyone help me in getting precision value without fluctuation of voltage value?

I am pasting the code for your understanding.

void setup() {

Serial.begin(9600);
}

void loop() {

int sensorValue = analogRead(A0);

float voltage = (sensorValue) * (5.0 / 1023.0);

Serial.println(voltage, 4); //Input Voltage Value

float Torque = ((241.96 * voltage - 36.236));

Serial.println(Torque, 4); //Torque Value

delay(3000);
}

#2

The resolution of the ADC is 5/1024 = 5 mV. So your fluctuations are two ADC points, which is within normal error.

Then there's the possible fluctuation of your 5V Vcc reference, which is an issue if your strain gauge produces an absolute rather than ratiometric voltage as output. In this case you can stabilise readings by bringing down the output to the 0-1.1V range, and enabling the built-in analog reference.

Without knowing the exact sensor you use, and the exact circuit diagram, this is all I can say about your problem.

#3

Please post full details of the hardware you mention, ie datasheets if possible, and your circuit.

#4

Don't know your hardware. Speed might be going up but torque is staying the same. This would cause the voltage to change but not the torque.

#5

You've necro-posted. Not normally useful as the OP is long since gone, they never responded at the time even.

And you've not even read the posting carefully enough to understand it either!

#6