63 lines
1.6 KiB
C++
63 lines
1.6 KiB
C++
#include <Wire.h>
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int M3200address = 0x28; // 0x28, 0x36 or 0x46, depending on the sensor.
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float maxPressure =100; // pressure in PSI for this sensor, 100, 250, 500, ... 10k.
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byte status;
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unsigned long pressureMillis = 0;
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const int pressureTiming = 500; // 500ms every data acquisition
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void setup (){
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Serial.begin(9600);
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Serial.println("M3200 initializing");
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Wire.begin();
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}
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void loop(){
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if (millis()-pressureMillis >= pressureTiming){
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pressureMillis = millis();
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Wire.requestFrom(M3200address,4); // request 4 bytes
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int n = Wire.available();
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if( n == 4){
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status = 0;
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uint16_t rawP; // pressure data from sensor
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uint16_t rawT; // temperature data from sensor
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rawP = (uint16_t) Wire.read(); // upper 8 bits
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rawP <<= 8;
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rawP |= (uint16_t) Wire.read(); // lower 8 bits
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rawT = (uint16_t) Wire.read(); // upper 8 bits
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rawT <<= 8;
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rawT |= (uint16_t) Wire.read(); // lower 8 bits
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status = rawP >> 14; // The status is 0, 1, 2 or 3
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rawP &= 0x3FFF; // keep 14 bits, remove status bits
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rawT >>= 5; // the lowest 5 bits are not used
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// The math could be done with integers, but I choose float for now
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float pressure = ((rawP - 1000.0) / (15000.0 - 1000.0)) * maxPressure;
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float temperature = ((rawT - 512.0) / (1075.0 - 512.0)) * 55.0;
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Serial.print("Status = ");
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Serial.println(status);
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Serial.print( "Pressure = ");
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Serial.println( pressure);
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Serial.print( "Temperature = ");
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Serial.println( temperature);
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Serial.println("-------------------------------------");
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}else{
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Serial.println( "M3200 Pressure Transducer not Detected");
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}
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}
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} |