I'm trying to build a pressure data logger using an Arduino and Mindman MP47P-03-F1 (https://www.mindman.com.tw/proimages/pdf/E_MP47_S.pdf) pressure sensor, the sensor is connected to an outer 12-24 VDC power source. I've connected the analog wire to the the Arduino's A0 and added another wire from the GND to the sensor. I get a stable voltage (~1V) reading but the pressure is wrong and it doesn't respond to pressure changes. Can someone tell me what I'm doing wrong? this is the sample code:
const int analogPin = A0; const float slope = -0.1; const float intercept = 0.6; const unsigned long startTime = millis(); void setup() { Serial.begin(9600); Serial.println("Time (s)\t\tPressure (MPa)"); } void loop() { unsigned long elapsedTime = millis() - startTime; int sensorValue = analogRead(analogPin); float voltage = sensorValue * (5.0 / 1023.0); float pressure = slope * (voltage - intercept); Serial.println(sensorValue); Serial.print(elapsedTime / 1000.0); Serial.print("\t\t"); Serial.println(pressure); delay(1000); } edit: i've changed the code to as suggested by some on the arduino forum:
const int sensorPin = A0; const int offset = 201; // zero pressure adjust const int fullScale = 1023; // max pressure adjust float sensorType = 1000.0; // kPa float pressure; // final pressure const unsigned long startTime = millis(); void setup() { Serial.begin(9600); } void loop() { unsigned long elapsedTime = millis() - startTime; pressure = (analogRead(sensorPin) - offset) * sensorType / (fullScale - offset); Serial.print(analogRead(sensorPin)); Serial.print("\t\t"); Serial.print(elapsedTime / 1000.0); Serial.print("\t\t"); Serial.println(pressure, 4); delay(1000); } the pressure is 0 but i keep getting jumps in the readings of the pressure when no pressure is applied. here is the picture of the wiring. 