Arduino library for for the SDP31 and SDP32 pressure sensors designed and manufactured by Sensirion.

1. Install
2. Examples
3. API
   1. Public
   2. Private
4. License

Just drop SDP3x.h and SDP3x.cpp into your own project, and off you go.

1. Download: SDP3X.zip
2. From the Arduino IDE:

• Sketch > Include Library > Add .ZIP Library...
• Navigate to SDP3X.zip
• Click "OK"

#include <SDP3x.h>

using namespace SDP3X;

SDP3x sensor(Address1,MassFlow);

void setup() {
  Wire.begin();
  sensor.begin();
}

#include <SDP3x.h>

using namespace SDP3X;

SDP3x sensor(Address1,MassFlow);

void setup() {
  Wire.begin();
  sensor.begin();
  sensor.startContinuous(false);
}

bool status;
int16_t pressure;

void loop() {
  delay(1000);
  status = sensor.readMeasurement(&pressure, NULL, NULL);
}

While there are many public constants in this library, there are two sets that you actually need to worry about.

Addresses

Address1, Address2, and Address3 are used to specify the three possible I2C addresses for the SDP3X sensors. These are actually 0x21, 0x22, and 0x23 respectively, but have been made constants for ease of use.

Temperature Compensation

The SDP3X sensors support two different temperature compensation modes that you may choose according to your target application.

1. MassFlow sets the compensation mode that is optimal for applications in which you are measuring the Mass Flow Rate of a substance.
2. DiffPressure sets the compensation mode that is optimal for applications is which you are measuring Gauge pressure (accounts for atmospheric pressure).

This function creates a new SDP3x object and takes in the following attributes:

This function must be called for each sensor. It communicates with the sensor to determine the model (SDP31 or SDP32) in order to provide the correct scaling factors.

This function begins the continuous sampling mode of the SDP3X sensors. A new reading will be taken at 1ms intervals. When continuous sampling is occurring, each sample may either be averaged with all samples since the last time the Master read a sample (average=true) or every new sample may replace the previous value (average=false).

This function stops the continuous sampling process. This may be done to preserve power or because readings are no longer needed.

This function tells a sensor to take a new reading while not in continuous sampling mode. This is useful when using a timer to set the sampling rate. Triggered measurements also support clock stretching (stretching=true), which delays a Read response to the Master when a new sample is not yet available (ie. blocking read). If disabled (stretching=false), a Read will fail entirely if it occurs less than 45ms after a trigger was sent.

This function reads the current sensor measurements (pressure and temperature). This may be used periodically (continuous mode) or in a call-back when monitoring interrupts (trigger mode). Both "temp" and "scale" should be left NULL if not used. This may reduce read times by not requesting more data than needed.

pressure and temp are returned as raw values without scale factors applied. These scale factors may be read using getPressureScale and getTemperatureScale respectively. In cases where both the SDP31 and SDP32 are used for the same application, and I2C communication is not heavy, the scale parameter of this function may be used rather than repeated calls to getPressureScale for each sensor.

This function reads the sensor's internal information. If a serial number is not needed, "serial" should be set to NULL. This will reduce read times.

This function resets the device to default settings.

WARNING: This will reset all other I2C devices on the bus that follow this convention.

This function gets the Pressure Scaling Factor for this sensor. It does require communicating on the I2C bus and does not change during execution.

This function gets the Temperature Scaling Factor for this sensor. It does require communicating on the I2C bus and does not change during execution.

This function writes an I2C command to the sensor.

This function reads multiple words of data from the the sensor. Each word consists of a 16-bit value, followed by an 8-bit CRC. Verification of the CRC is performed automatically by this function. The CRC byte only applies to the current word and is reset in between words.

MIT License

Copyright (c) 2018 Bryan T. Meyers

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.