Hi,
I am trying to interface Load cell with arduino UNO(328P) and using INA125P as instrumentation amplifier i have 5 wire load cell
RED = E+
Black = E-
Green = S+
WHITE = S-
Shield wire
i am using this as a reference for connection and code.
the values i am getting as a result vary too much that there is too much difference in values with NO LOAD applied. i havn't use the shield wire do i have to use it?
Attached is the screenshot of my output on Serial Monitor and my connection scheme.
Code:
// Arduino as load cell amplifier
// by Christian Liljedahl
// christian.liljedahl.dk
// Load cells are linear. So once you have established two data pairs, you can interpolate the rest.
// Step 1: Upload this sketch to your arduino board
// You need two loads of well know weight. In this example A = 10 kg. B = 30 kg
// Put on load A
// read the analog value showing (this is analogvalA)
// put on load B
// read the analog value B
// Enter you own analog values here
float loadA = 10; // kg
int analogvalA = 200; // analog reading taken with load A on the load cell
float loadB = 30; // kg
int analogvalB = 600; // analog reading taken with load B on the load cell
// Upload the sketch again, and confirm, that the kilo-reading from the serial output now is correct, using your known loads
float analogValueAverage = 0;
// How often do we do readings?
long time = 0; //
int timeBetweenReadings = 2000; // We want a reading every 200 ms;
void setup() {
Serial.begin(9600);
}
void loop() {
int analogValue = analogRead(0);
// running average - We smooth the readings a little bit
analogValueAverage = 0.99analogValueAverage + 0.01analogValue;
// Is it time to print?
if(millis() > time + timeBetweenReadings){
float load = analogToLoad(analogValueAverage);
Serial.print("analogValue: ");Serial.println(analogValueAverage);
Serial.print(" load: ");Serial.println(load,5);
time = millis();
}
}
float analogToLoad(float analogval){
// using a custom map-function, because the standard arduino map function only uses int
float load = mapfloat(analogval, analogvalA, analogvalB, loadA, loadB);
return load;
}
float mapfloat(float x, float in_min, float in_max, float out_min, float out_max)
{
return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}
//Reference www.instructables.com/id/Arduino-Load-Cell-Scale/step3/The-Code/
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