How to convert ascii data to floating point?

Hi guys.

i have a problem with my project and i need your help.

the problem is about data type conversion.

i use an app to send gravity_sensor data via UDP on my phone.

This is a desription of the app i use.

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USAGE INSTRUCTIONS:

The data is stored within the app as a float array. See the format below.

Format: [ X Acceleration, Y Acceleration, Z Acceleration, X Gravity, Y Gravity, Z Gravity, X Rotation Rate, Y Rotation Rate, Z Rotation Rate, X Orientation (Azimuth), Y Orientation (Pitch), Z Orientation (Roll), deprecated, deprecated, Ambient Light, Proximity, Keyboard Buttons 1 - 8 ]

%%%%%%%%%%%%%

and, i wrote these lines and get result in MATLAB.

 fopen(UDPComIn);

 csvdata=fscanf(UDPComIn)

 ans =
 KKun

this is the problem. what i wanted was floating point data like (-0.001). but, the result data type looked like ASCII code type.

so here are my question.

1) Is there any method to extract floating point data from a float array in UDP ?

2) if not, how can i convert ascii data to floating point?

i will wait your reply soon

Answer 1

[Walter Roberson]

The default for fscanf on UDP objects is %c format, but the packets do not contain text. You should be using fread() on the UDP object, specifying '*float' . You might also need to specify the endian order; see https://www.mathworks.com/help/instrument/byteorder.html

[YoungMin Ho]

it works. thanks!

Answer 2

[Image Analyst]

That won't work. If you passed UDPComIn into fopen(), then it's a string with a filename in it. So you can't pass that in to fscanf. Anyway, you didn't even pass a file ID or a format specifier string into fscanf(). Check the documentation for fscanf(). Or use str2double() instead, if you can get your numbers in an ASCII string.

[Walter Roberson]

"If you passed UDPComIn into fopen(), then it's a string with a filename in it."

That is not correct. You can fopen() on Serial objects and TCP objects and UDP objects.