Barometer Bricklet¶

Features¶

• Measures air pressure and altitude changes
• Resolution 0.012hPa / 0.1m
• Range 10 to 1200hPa

Description¶

The Barometer Bricklet can be used to extend the features of Bricks by the capability to measure air pressure in range of 10 to 1200hPa with a resolution of 0.012hPa. The measurement is temperature compensated internally.

The Bricklet is equipped with a MS5611-01BA01 sensor which is designed to be used as an altimeter, too. But since the air pressure is changing significantly even over a short period time the achievable accuracy is limited. One possible solution to achieve higher accuracy and stability of the altitude measurement is to perform sensor fusion with the sensor data of an IMU Brick (see Youtube video).

Technical Specifications¶

Resources¶

• MS5611 datasheet (Download)
• Schematic (Download)
• Outline and drilling plan (Download)
• Source code and design files (Download)
• 3D model (View online | Download: STEP, FreeCAD)

Test your Barometer Bricklet¶

To test a Barometer Bricklet you need to have Brick Daemon and Brick Viewer installed. Brick Daemon acts as a proxy between the USB interface of the Bricks and the API bindings. Brick Viewer connects to Brick Daemon. It helps to figure out basic information about the connected Bricks and Bricklets and allows to test them.

Connect the Barometer Bricklet to a Brick with a Bricklet Cable.

If you connect the Brick to the PC over USB, you should see a new tab named "Barometer Bricklet" in the Brick Viewer after a moment. Select this tab. If everything went as expected you can now see the air pressure in hPa and a graph that shows the air pressure over time.

After this test you can go on with writing your own application. See the Programming Interface section for the API of the Barometer Bricklet and examples in different programming languages.

Understanding Air Pressure¶

Air pressure is a complex topic. Two frequently asked questions are: Why does the air pressure value of the Barometer Bricklet differs from the value in the weather forecast and why does the altitude value differ from the actual altitude of the measuring location?

QFF = QFE / [1 - Tg * H / (273.15 + Tfe + Tg * H)] ^ (0.034163 / Tg)

Case¶

A laser-cut case for the Barometer Bricklet is available.

The assembly is easiest if you follow the following steps:

• Screw spacers to the Bricklet,
• screw bottom plate to bottom spacers,
• build up side plates,
• plug side plates into bottom plate and
• screw top plate to top spacers.

Below you can see an exploded assembly drawing of the Barometer Bricklet case:

Hint: There is a protective film on both sides of the plates, you have to remove it before assembly.

Programming Interface¶

See Programming Interface for a detailed description.