Module/Bosch BMP085
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Overview
The Bosch BMP085 is a barometer/pressure sensor. There is an alternative float number implementation available that seems to offer less noise, not implemented yet.
The device was tested in a simple static noise comparsion setup.
| Module name | sensors/baro_bmp |
| Sensor type | barometer, temperature |
| Range (baro) | 30 kPa .. 1100 kPa |
| Range (temp) | -40°C .. +85°C |
| Resolution (baro) | 3 Pa |
| Resolution (temp) | 0.1°C |
| Refresh rate | 8Hz |
| I2C address | 0xEE |
Hardware
The sensor directly interfaces to the 3.3V I2C port of the autopilots and is supplied by +3.3V.
Supplier: Sparkfun
Wiring
| Autopilot I2C pin | Autopilot I2C | Bosch BMP085 |
| 1 | GND | GND |
| 2 | ||
| 3 | +3.3V | VCC |
| 4 | SDA | SDA |
| 5 | SCL | SCL |
Usage
To use it load the baro_bmp module:
| File: conf/airframes/myplane.xml |
<modules>
...
<load name="baro_bmp.xml"/>
</modules>
|
Configuration
To see the sensors data in the log file every time new data is available, set SENSOR_SYNC_SEND in your airframe file.
If you omit SENSOR_SYNC_SEND from your airframe file, you will still get the data, but at 1/10 of the available rate.
| File: conf/airframes/myplane.xml |
<modules>
...
<load name="baro_bmp.xml">
<define name="SENSOR_SYNC_SEND"/>
</load>
</modules>
|
Result message
The raw data (UP/UT) and the converted result (press/temp) is written to the log file.
| File: conf/messages.xml |
<message name="BMP_STATUS" id="84">
<field name="UP" type="int32"/>
<field name="UT" type="int32"/>
<field name="press" type="int32" unit="Pa"/>
<field name="temp" type="int32" unit="10x_deg_celsius"/>
</message>
|
Sample log file lines
8.272 123 BMP_STATUS 336765 28975 98628 219 8.507 123 BMP_STATUS 336765 28973 98629 219 8.741 123 BMP_STATUS 336775 28975 98629 219 8.973 123 BMP_STATUS 336778 28973 98630 219