如何使用LSM303DLHC加速度计的示例

你好Antho，
 
 
 我们目前正在创建该论坛的一部分，其中包含使用ST的MEMS的应用示例。我也将为您的应用程序添加一个示例。
 
 一旦我们有了代码，我也可以在这里作为参考发布。
 
 非常感谢你，
 
 蒂亚戈雷斯



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Hello Antho,


We are currently creating a section of this forum to contain examples of applications using ST's MEMS. I will add one example for you application too.

Once we have the codes, I can also post it here as a reference.

Thank you very much,

Thiago Reis

嗨Thiago，
 
 
感谢您的时间。我认为这个新部分是一个好主意，对我这样的初学者来说可能非常有用。
 
Antho



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Hi Thiago,


Thank you for your time. I think that this new section is a good idea, it might be very helpful for beginners like me.

Antho

Antho，
 
 如果您仍在查看有关LSM303使用情况的其他信息，我建议您查看F401演示文件夹中的selftest.c文件。您可以使用I2C连接读取传感器数据（例如LSM303DHLC_CompassReadAcc）。获得加速度计和罗盘数据后，应将其与陀螺仪数据（来自L3GD20）相结合。
 
 加速度计有很多短期噪音，但长期稳定性好。陀螺仪噪音很小，但漂移很差。您可以使用卡尔曼滤波器来组合数据流，简单的低通和高通滤波器，或者附加方法（例如基于模型的偏差调整）。



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Antho,

Just in case that you are still looking some additional information about the LSM303 usage, I would recommend that you look the selftest.c file in the F401 demonstration folder.  There you have the code to read the sensor data (such as LSM303DHLC_CompassReadAcc) using the I2C connection.  Once you have the accelerometer and compass data, you should combine that with the gyro data (from L3GD20).

The accelerometer has a lot of short term noise, but good long term stability.  The gyro has little noise, but it has a bad drift.  You can use a Kalman filter to combine the data streams, simple low pass and high pass filters, or add-hoc methods (such as model based bias adjustment).

嗨Thiago，
 
 很高兴知道您正在为应用程序添加单独的部分。
 链接http://www.st.com/web/en/catalog/tools/PF257534#



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Hi Thiago,

Good to know that you are adding a separate section for the applications.
The link http://www.st.com/web/en/catalog/tools/PF257534#

嗨，
 
 
感谢您的时间奥利，您的回复非常有帮助。
实际上，我正在尝试测试学校项目的惯性测量单元的准确性。这就是我需要从加速度计和陀螺仪获取输出数据的原因。
 
但首先，我试图利用输出数据打开与加速方向匹配的LED（如陀螺仪的演示）。我在寄存器中将线性加速度范围设置为8g，但我无法确定函数''LSM303DLHC_Read（ACC_I2C_ADDRESS，LSM303DLHC_OUT_X_L_A，6，tmpbuffer）'返回哪种数据。
 
在数据手册中，提到16位数据输出以2的补码表示。然后将此数据转换为浮点数。缓冲区声明是：float buffer [6]。但是，在我读过的不同程序中，X和Y值由Xval = buffer [0]和Yval = buffer [1]或buffer [2]定义。
但是，我们不应该通过上面的函数获得Xval（参数：LSM303DLHC_OUT_X_L_A）吗？为什么浮点值在8位转换为测试（''if（（int8_t）Buffer [0]＆lt; -2）''）？
 
关于数据过滤，我将研究卡尔曼滤波器，谢谢你的想法。
 
亲切的问候，
 
Antho



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Hi,


Thanks for your time Ollie, your reply has been very helpful.
Actually, I am trying to test the accuracy of the Inertial Measurement Unit for a school project. That is why I need to get the output data from both the accelerometer and the gyroscope.

But first, I am trying to exploit the output data to turn on the LED matching with the acceleration direction (as in the demo of the gyroscope). I set the linear acceleration range at 8g in the register but I have not been able to determine which kind of data is returned by the function ''LSM303DLHC_Read(ACC_I2C_ADDRESS,LSM303DLHC_OUT_X_L_A,6,tmpbuffer)''.

In the data sheet, it is mentioned that the 16 bit data output is expressed in 2's complement. this data is then converted into a float. The buffer declaration is : float buffer[6]. However, in the different programs I read, the X and Y values were define by Xval = buffer[0] and Yval = buffer[1] or buffer[2].
But, aren't we supposed to get only the Xval by the function above (parameter : LSM303DLHC_OUT_X_L_A) ? And why is the float value converted in 8 bit for the test (''if((int8_t)Buffer[0] < -2)'') ?

About the data filtering, I will look into the Kalman filter, thank you for the idea.

Kind regards,

Antho

你好Sudhi，
 
 
 您是否可以下载所需的软件？
 如果没有，请通过thiago.reis@st.com向我发送一条消息，其中包含您的联系信息和项目说明
 
 谢谢，
 
 蒂亚戈



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Hello Sudhi,


Were you able to download the software that you needed?  
If not, please send me a message with your contact information and project description at thiago.reis@st.com

Thank you,

Thiago