Pressure and Temp. sensor (Map)

Using Arduino Programming Questions
1

Hey Guys, i got an bosch Motorsport T-map sensor (0281006076) connetet to my arduino uno. 5v+, gnd, a5 goes to the NTC sensor, and a0 goes to the pressure sensor. you can lok up the datasheet for this sensor on google.
I just want the pressure and temp. displayd on my I2C Screen. the screen is connectet to scl,sda, 5v,gnd.
so heres my code that dont work maybe anyone can help:

#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2); // set the LCD address to 0x27 for a 16 chars and 2 line display

const int pressurePin = A0;
const int ntcPin = A5;


void setup()
{
  lcd.init();         // initialize the lcd
  lcd.backlight();    // Turn on the LCD screen backlight
}

float readPressure() {
  int sensorValue = analogRead(pressurePin);
  float voltage = sensorValue * (5.0 / 1023.0);
  float pressure = (voltage - 0.5) * (300.0 / 4.0) - 50; // Umrechnung gemäß Kennlinie (-0.5 bis 3 bar)
  return pressure;
}

float readTemperature() {
  int ntcValue = analogRead(ntcPin);
  return temperature;
}

float calculateTemperature(float resistance) {
  float tempValues[] = {-40, -35, -30, -25, -20, -15, -10, -5, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130};
  float resValues[] = {45303, 34273, 26108, 19999, 15458, 12000, 9358, 7413, 5895, 4711, 3791, 3068, 2499, 2056, 1706, 1421, 1180, 987.4, 833.8, 702.7, 595.4, 508.2, 435.6, 374.1, 322.5, 279.5, 243.1, 212.6, 186.6, 165.0, 146.9, 131.9, 119.2, 108.2, 98.29};
  
  for (int i = 0; i < 34; i++) {
    if (resistance >= resValues[i] && resistance <= resValues[i + 1]) {
      float slope = (tempValues[i + 1] - tempValues[i]) / (resValues[i + 1] - resValues[i]);
      return tempValues[i] + slope * (resistance - resValues[i]);
    }
  }
  return -999; // Fehlerwert

}


void loop()
{
 float pressure = readPressure();
  float temperature = readTemperature();

  lcd.setCursor(0, 0);
  lcd.print("Druck:");
  lcd.setCursor(0, 1);
  lcd.print("Temp:");

  // Display pressure
  lcd.setCursor(6, 0);
  lcd.print(pressure, 2);
  lcd.print(" bar   "); // Padding to clear old data

  // Display temperature
  lcd.setCursor(6, 1);
  lcd.print(temperature, 1);
  lcd.print(" C     "); // Padding to clear old data

  delay(500); // Aktualisierung alle 500 ms

}
````
2

You'll get more responses if you save us that work and post a link.

3

A5 is also the I2C SCL pin. And you have an I2C display in your code.

4

Yes, it does work. Maybe it does not do what you want it to do, but it does something! Why don't you try to describe the situation a little better?

5
6

What do you mean a5 is also the scl pin? i got a seperate acl and sda pin on my bord.

7

sure, it shows the Druck/pressure but not correct. it says 32-33 bar but it should be around 1 (atmospheric pressure). and temp. is always -999

8

Look at a schematic for the Uno.

See that the pin PC5 on the 328P is brought out to both the SCL pin and the A5 pin. It's the same pin brought out to 2 different places.

9

ok thx i change the a5 pin (ntc) to a3 works.

10

now i got all problems solved. here is the code. `#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 16, 2); // LCD-Adresse auf 0x27 für ein 16x2-Display setzen

const int pressurePin = A1; // Pin für Drucksensor
const float sensorMin = 0.5; // Minimum voltage from sensor (0.2 bar)
const float sensorMax = 4.5; // Maximum voltage from sensor (3.0 bar)
const float pressureMin = 0.2; // Minimum pressure in bar
const float pressureMax = 3.0; // Maximum pressure in bar
const int ntcPin = A3; // Pin für Temperatursensor

// Kalibrierungsfaktor zur Anpassung des Drucks
float pressureCalibrationFactor = 1.0; // Abweichung

// Offset-Faktor zur Anpassung des Drucks
float pressureOffset = 0.0; // Offset-Faktor, der zum Druck addiert wird

void setup() {
lcd.init(); // Initialisiere das LCD
lcd.backlight(); // LCD-Hintergrundbeleuchtung einschalten
}

float readPressure() {
int sensorValue = analogRead(pressurePin); // Lese analogen Wert vom Drucksensor
float voltage = sensorValue * (5.0 / 1023.0); // Spannung umrechnen

// Werte aus dem Diagramm
float c0 = 5.4 / 280.0;
float c1 = 0.85 / 280.0;
float supplyVoltage = 5.0; // Versorgungsspannung in Volt

// Berechnung des absoluten Drucks in kPa gemäß der Formel
float pressure_kPa = (280.0 / 0.85) * ((voltage / supplyVoltage) - c0);

// Umwandlung von kPa in Bar, Anwendung des Kalibrierungsfaktors und des Offset-Faktors
float pressure_bar = (pressure_kPa / 100.0) * pressureCalibrationFactor + pressureOffset;

return pressure_bar;
}

float readTemperature() {
int ntcValue = analogRead(ntcPin); // Lese analogen Wert vom NTC
float voltage = ntcValue * (5.0 / 1023.0); // Spannung umrechnen

// Berechne den Widerstand des NTC
float resistance = (10000.0 * voltage) / (5.0 - voltage); // 10kΩ Spannungsteiler

// Berechne die Temperatur aus dem Widerstand
float temperature = calculateTemperature(resistance);
return temperature;
}

float calculateTemperature(float resistance) {
// Temperatur- und Widerstandswerte aus der Kennlinie
float tempValues[] = {-40, -35, -30, -25, -20, -15, -10, -5, 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, 120, 125, 130};
float resValues[] = {45303, 34273, 26108, 19999, 15458, 12000, 9358, 7413, 5895, 4711, 3791, 3068, 2499, 2056, 1706, 1421, 1180, 987.4, 833.8, 702.7, 595.4, 508.2, 435.6, 374.1, 322.5, 279.5, 243.1, 212.6, 186.6, 165.0, 146.9, 131.9, 119.2, 108.2, 98.29};

for (int i = 0; i < 34; i++) {
if (resistance >= resValues[i + 1] && resistance <= resValues[i]) {
float slope = (tempValues[i] - tempValues[i + 1]) / (resValues[i] - resValues[i + 1]);
return tempValues[i + 1] + slope * (resistance - resValues[i + 1]);
}
}
return -999; // Fehlerwert
}

void loop() {
float pressure = readPressure();
float temperature = readTemperature();

lcd.setCursor(0, 0);
lcd.print("Druck:");
lcd.setCursor(0, 1);
lcd.print("Temp:"); // Anzeige Temp: für Temperatur

// Display pressure
lcd.setCursor(6, 0);
lcd.print(pressure, 2);
lcd.print(" bar "); // Padding to clear old data

// Display temperature
lcd.setCursor(6, 1);
if (temperature != -999) {
lcd.print(temperature, 1);
} else {
lcd.print("Err ");
}
lcd.print("C "); // Padding to clear old data

delay(200); // Aktualisierung alle 500 ms
}
so when i try to improve the fload temp values to something like this float tempValues[] = {-40, -39, -38, -37, -36, -35, -34, -33, -32, -31, -30, -29, -28, -27, -26, -25, -24, -23, -22, -21, -20, -19, -18, -17, -16, -15, -14, -13, -12, -11, -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76,
77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130};
float resValues[] = {45303, 42824.7, 40489.7, 38290.9, 36221.1, 34273, 32439.5, 30713.5, 29087.7, 27554.9, 26108, 24740.5, 23448.8, 22229.9, 21080.9, 19999, 18980.9, 18022.4, 17118.7, 16265.5, 15458, 14692.1, 13965.4, 13275.8, 12621.4, 12000, 11410,
10850.9, 10322.7, 9825.1, 9358, 8920.8, 8510.9, 8125.1, 7760.2, 7413, 7080.9, 6763.2, 6459.8, 6170.4, 5895, 5633.3, 5384.7, 5148.6, 4924.2, 4711, 4508.3, 4315.5, 4132, 3957.4, 3791, 3632.3, 3481, 3336.8, 3199.2, 3068, 2942.8, 2823.6, 2709.9, 2601.8,
2499, 2401.3, 2308.5, 2220.2, 2136.1, 2056, 1979.5, 1906.5, 1836.7, 1769.9, 1706, 1644.9, 1586.5, 1530.6, 1477.2, 1421, 1371.1, 1323.8, 1278.9, 1236.3, 1180, 1144.3, 1110.1, 1077.3, 1045.8, 987.4, 958.6, 931.1, 904.9, 879.9, 833.8, 805.9, 778.8, 752.5,
727.1, 702.7, 679.3, 657, 635.6, 615.1, 595.4, 576.5, 558.4, 541, 524.3, 508.2, 492.7, 477.7, 463.2, 449.2, 435.6, 422.5, 409.8, 397.5, 385.6, 374.1, 363, 352.3, 342, 332.1, 322.5, 313.3, 304.4, 295.8, 287.5, 279.5, 271.7, 264.2, 256.9, 249.9, 243.1,
236.6, 230.3, 224.2, 218.3, 212.6, 207.1, 201.8, 196.6, 191.5, 186.6, 181.8, 177.1, 172.5, 168.1, 163.8, 159.6, 155.6, 151.7, 147.9, 144.2, 140.6, 137.1, 133.8, 130.5, 127.3, 124.2, 121.2, 118.3, 115.4, 112.7, 110, 107.5, 105, 102.6, 100.2, 97.9, 95.7,
93.5, 91.4, 89.3};` the screen just turns on without showing anything. Is my uno r3 to weak?

11

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