MS45XX differential or gauge type of pressure sensor for e.g measuring airspeed.

This sensor module is using the MS45xxDO digital pressure sensor with readings via I2C. Needs to be a versions with 14bit pressure and 11bit temperature data output.

Example for airframe file

Add to your firmware section: This example contains all possible configuration options, not all of them are mandatory!

 <module name="airspeed_ms45xx_i2c">
   <define name="MS45XX_I2C_DEV" value="i2cX" />
   <define name="MS45XX_I2C_ADDR" value="0x50" />
   <define name="MS45XX_PRESSURE_TYPE" value="0|1" />
   <define name="MS45XX_PRESSURE_RANGE" value="1|2|4|5|10|15|20|30|50|100|150" />
   <define name="MS45XX_OUTPUT_TYPE" value="0|1" />
   <define name="MS45XX_SYNC_SEND" value="TRUE|FALSE" />
   <define name="MS45XX_PRESSURE_SCALE" value="1.05" />
   <define name="MS45XX_PRESSURE_OFFSET" value="8618.4" />
   <define name="MS45XX_AIRSPEED_SCALE" value="1.6327" />
   <define name="MS45XX_LOWPASS_TAU" value="0.15" />
   <define name="USE_AIRSPEED_MS45XX" value="TRUE|FALSE" />
 </module>

Module configuration options

Define Options

name: MS45XX_I2C_DEV value: i2cX
Description: set i2c peripheral (default: i2c2)
name: MS45XX_I2C_ADDR value: 0x50
Description: i2c slave address (default: 0x50)
name: MS45XX_PRESSURE_TYPE value: 0|1
Description: Pressure Differential or Gauge, default is Differential
name: MS45XX_PRESSURE_RANGE value: 1|2|4|5|10|15|20|30|50|100|150
Description: pressure range in psi (default: 1)
name: MS45XX_OUTPUT_TYPE value: 0|1
Description: set to 0 for output type A, to 1 for output type B (default: type A)
name: MS45XX_SYNC_SEND value: TRUE|FALSE
Description: flag to enable sending every new measurement via telemetry (default:FALSE)
name: MS45XX_PRESSURE_SCALE value: 1.05
Description: pressure scaling factor to convert raw output to Pa (default: set according to pressure range and output type according to datasheet)
name: MS45XX_PRESSURE_OFFSET value: 8618.4
Description: pressure offset in Pa (default: set according to pressure range and output type according to datasheet)
name: MS45XX_AIRSPEED_SCALE value: 1.6327
Description: quadratic scale factor to convert differential pressure to airspeed
name: MS45XX_LOWPASS_TAU value: 0.15
Description: Time constant for second order Butterworth low pass filter
name: USE_AIRSPEED_MS45XX value: TRUE|FALSE
Description: Set airspeed in state interface for this sensor

Module functions

Init Functions

These initialization functions are called once on startup.

ms45xx_i2c_init()

Event Functions

These event functions are called in each cycle of the module event loop.

ms45xx_i2c_event()

Periodic Functions

These functions are called periodically at the specified frequency from the module periodic loop.

ms45xx_i2c_periodic()
- Frequency in Hz: 100.
- Autorun: LOCK
  Periodic function automatically starts after init and can't be stopped.

Files

Header Files

The following headers are automatically included in modules.h

airspeed_ms45xx_i2c.h

Source Files

modules/sensors/airspeed_ms45xx_i2c.c

Raw airspeed_ms45xx_i2c.xml file:

<!DOCTYPE module SYSTEM "module.dtd">
<module name="airspeed_ms45xx_i2c" dir="sensors">
  <doc>
    <description>
      MS45XX differential or gauge type of pressure sensor for e.g measuring airspeed.
      This sensor module is using the MS45xxDO digital pressure sensor with readings via I2C.
      Needs to be a versions with 14bit pressure and 11bit temperature data output.
    </description>
    <define name="MS45XX_I2C_DEV" value="i2cX" description="set i2c peripheral (default: i2c2)"/>
    <define name="MS45XX_I2C_ADDR" value="0x50" description="i2c slave address (default: 0x50)"/>
    <define name="MS45XX_PRESSURE_TYPE" value="0|1" description="Pressure Differential or Gauge, default is Differential"/>
    <define name="MS45XX_PRESSURE_RANGE" value="1|2|4|5|10|15|20|30|50|100|150" description="pressure range in psi (default: 1)"/>
    <define name="MS45XX_OUTPUT_TYPE" value="0|1" description="set to 0 for output type A, to 1 for output type B (default: type A)"/>
    <define name="MS45XX_SYNC_SEND" value="TRUE|FALSE" description="flag to enable sending every new measurement via telemetry (default:FALSE)"/>
    <define name="MS45XX_PRESSURE_SCALE" value="1.05" description="pressure scaling factor to convert raw output to Pa (default: set according to pressure range and output type according to datasheet)"/>
    <define name="MS45XX_PRESSURE_OFFSET" value="8618.4" description="pressure offset in Pa (default: set according to pressure range and output type according to datasheet)"/>
    <define name="MS45XX_AIRSPEED_SCALE" value="1.6327" description="quadratic scale factor to convert differential pressure to airspeed"/>
    <define name="MS45XX_LOWPASS_TAU" value="0.15" description="Time constant for second order Butterworth low pass filter"/>
    <define name="USE_AIRSPEED_MS45XX" value="TRUE|FALSE" description="Set airspeed in state interface for this sensor"/>
  </doc>
  <settings>
    <dl_settings>
      <dl_settings NAME="MS45XX">
        <dl_setting min="0" max="1" step="1" values="FALSE|TRUE" var="ms45xx.sync_send" type="bool" shortname="sync_send" module="modules/sensors/airspeed_ms45xx_i2c" param="MS45XX_SYNC_SEND" persistent="true"/>
        <dl_setting min="0" max="1" step="1" values="FALSE|TRUE" var="ms45xx.autoset_offset" type="bool" shortname="autoset offset" module="modules/sensors/airspeed_ms45xx_i2c" param="MS45XX_SYNC_SEND" persistent="true"/>
        <dl_setting min="0.9" max="1.2" step="0.01" var="ms45xx.pressure_scale" type="float" shortname="PressScale" module="modules/sensors/airspeed_ms45xx_i2c" param="MS45XX_PRESSURE_SCALE" persistent="true"/>
        <dl_setting min="0" max="1" step="1" values="FALSE|TRUE" var="ms45xx.pressure_type" type="bool" shortname="Type G" module="modules/sensors/airspeed_ms45xx_i2c" param="MS45XX_PRESSURE_TYPE" persistent="true"/>
        <dl_setting min="8300.0" max="8900.0" step="0.1" var="ms45xx.pressure_offset" type="float" shortname="PressOffset" module="modules/sensors/airspeed_ms45xx_i2c" param="MS45XX_PRESSURE_OFFSET" persistent="true"/>
        <dl_setting min="1.0" max="2.0" step="0.01" var="ms45xx.airspeed_scale" type="float" shortname="AirScale" module="modules/sensors/airspeed_ms45xx_i2c" param="MS45XX_AIRSPEED_SCALE" persistent="true"/>
      </dl_settings>
    </dl_settings>
  </settings>
  <header>
    <file name="airspeed_ms45xx_i2c.h"/>
  </header>
  <init fun="ms45xx_i2c_init()"/>
  <periodic fun="ms45xx_i2c_periodic()" freq="100."/>
  <event fun="ms45xx_i2c_event()"/>
  <makefile target="ap">
    <file name="airspeed_ms45xx_i2c.c"/>
  </makefile>
</module>