Below code for connecting 6 FSR 38.1mm Square type with Arduino UNO.
/* FSR testing sketch.
Connect one end of FSR to power, the other end to Analog 0.
Then connect one end of a 10K resistor from Analog 0 to ground
int fsrPins[] = {0, 1, 2, 3, 4, 5}; // Array to store all FSR pin numbers
int numFSRs = 6; // Number of FSRs connected
float fsrReadings[6]; // Array to store analog readings from each FSR
double fsrVoltages[6]; // Array to store voltages for each FSR
double fsrResistances[6]; // Array to store resistances for each FSR
double fsrConductances[6]; // Array to store conductances for each FSR
double fsrForces[6]; // Array to store forces for each FSR
double fsrWeights[6]; // Array to store weights for each FSR
int interval = 1; // Time interval between readings (in milliseconds)
unsigned long previousMillis = 0;
void setup(void) {
Serial.begin(9600); // We'll send debugging information via the Serial monitor
}
void loop(void) {
unsigned long currentMillis = millis();
if (currentMillis - previousMillis >= interval) {
previousMillis = currentMillis;
processFSRReadings(); // Call the asynchronous function to process FSR readings
}
}
// Asynchronous function to process FSR readings
void processFSRReadings() {
for (int i = 0; i < numFSRs; i++) {
fsrReadings[i] = analogRead(fsrPins[i]);
Serial.print("Analog reading " + String(i+1) + " = ");
Serial.println(fsrReadings[i]);
// analog voltage reading ranges from about 0 to 1023 which maps to 0V to 5V (= 5000mV)
fsrVoltages[i] = map(fsrReadings[i], 0, 1023, 0, 5000);
//Serial.print("Voltage reading " + String(i+1) + " in mV = ");
//Serial.println(fsrVoltages[i]);
if (fsrVoltages[i] == 0) {
//Serial.println("No pressure");
} else {
// The voltage = Vcc * R / (R + FSR) where R = 10K and Vcc = 5V
// so FSR = ((Vcc - V) * R) / V yay math!
fsrResistances[i] = 5000 - fsrVoltages[i]; // fsrVoltages is in millivolts so 5V = 5000mV
fsrResistances[i] *= 10000; // 10K resistor
fsrResistances[i] /= fsrVoltages[i];
//Serial.print("FSR resistance " + String(i+1) + " in ohms = ");
//Serial.println(fsrResistances[i]);
fsrConductances[i] = 1000000; // we measure in micromhos so
fsrConductances[i] /= fsrResistances[i];
//Serial.print("Conductance " + String(i+1) + " in microMhos: ");
//Serial.println(fsrConductances[i]);
// Use the two FSR guide graphs to approximate the force
if (fsrConductances[i] <= 1000) {
fsrForces[i] = fsrConductances[i] / 300; // The division by 350 is an empirical constant used to approximate the force based on experimental calibration.
fsrWeights[i] = fsrForces[i] / 9.80665;
//Serial.print("Force " + String(i+1) + " in Newtons: ");
//Serial.println(fsrForces[i]);
//Serial.print("Force " + String(i+1) + " in Kg: ");
//Serial.println(fsrWeights[i]);
} else {
fsrForces[i] = fsrConductances[i]-1000;
fsrForces[i] /= 250;
fsrWeights[i] = fsrForces[i] / 9.80665;
//Serial.print("Force " + String(i+1) + " in Newtons: ");
//Serial.println(fsrForces[i]);
//Serial.print("Force " + String(i+1) + " in Kg: ");
//Serial.println(fsrWeights[i]);
}
}
//Serial.println("--------------------");
}
}
And my output 10 samples with interval for same weight in different sensor.
below is my circuit connection.
I need to reduce the fluctuations in each FSR, so that i can able to calibrate for weight calculation.
Thanks in advance.