DFRobot Pressure Sensor0257 (Expert Help)

All,

Recently I purchased a DFRobot water pressure sensor. My "test" code is below. It appears to be functioning correctly although I did modify the sample code because I felt mine would give more accurate results.

Concern: I do not have a good way to test the pressure sensor unless I install into my application. The install is not easy and requires much work and time therefore I want to make certain my code is working correctly and accurately.

Does anyone have experience with the sensor? Does any have a sensor that can be tested with my code to confirm the function is 100% ok?

I am open to suggestions for my code. Please confirm it.

*Disclaimer: On the website it has examples of their code. I did not understand why they would multiple by 250 and 400... it confused me so I changed that portion of math based off what I thought was correct.



const float OffSet = .71 ; // See Calibration Note!
float V, V2Comp, PMpa, psi; // Voltage & Pressure


void setup() {
    Serial.begin(9600);
    Serial.println("/** Water Pressure Sensor Data **/");
}

void loop() {
    //Connect sensor’s output (SIGNAL) to Analog 0
V = (5. / 1023.)*analogRead(0);
V2Comp = (V-OffSet); //Target should be 0.0V with no load, static. 

PMpa = (1.0/4.5)*V2Comp;
psi = PMpa * 145.037738; //1Mpa = 145.037738psi


Serial.print("Voltage:");
Serial.print(V, 3);
Serial.print("V");

Serial.print("   Calibrated Voltage:");
Serial.print(V2Comp, 3);
Serial.print("V");

Serial.print("   Pressure(Mpa):");
Serial.print(PMpa, 3);
Serial.print(" Mpa");

Serial.print("   psi");
Serial.print(psi, 2);
Serial.println();
delay(3000);
}

The only way to be sure that the sensor and code are working correctly and accurately is to feed the sensor accurately known water pressure values, and compare the program output to those known values.

Fortunately water pressure is a direct, linear function of water column height. Just look up the conversion factor. So the test is easy.

Conversely, calibrate the sensor by working out the transformation that takes the computer output for the test cases and reproduces the known test pressure values.

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