# New Qt blocks and other helpful blocks

**URL:** <https://www.ruby-forum.com/t/new-qt-blocks-and-other-helpful-blocks/238130>\
**Category:** GNU Radio\
**Created:** [December 18, 2013, 7:12pm UTC](https://www.ruby-forum.com/t/new-qt-blocks-and-other-helpful-blocks/238130 "2013-12-18T19:12:35Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Detlef\_R](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/58f4c7/32.png) [@Detlef\_R](https://www.ruby-forum.com/u/Detlef_R)\
**Post date:** [December 18, 2013, 7:12pm UTC](https://www.ruby-forum.com/t/new-qt-blocks-and-other-helpful-blocks/238130/1 "2013-12-18T19:12:35Z")

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Hi everybody,

some time ago I stumbled over the problem that I missed a Qt version of  
some blocks. In particular I wanted to have a Qt numbersink and a  
Compass.  
Thus, I created them [1] with Qt designer and integrated them into a GR  
block. For now, they use Python. There are ‘.ui’ files that have to be  
used  
to generate the ‘.py’ files manually with pyuic4. Then they should  
install  
along with the other blocks.  
Along with the Qt blocks I converted one of the gr-specest blocks ‘DOA  
MUSIC’ to the GR 3.7 API. The code I used for this is from Balint  
Seeber’s  
gr-baz.  
Also I wanted to have a Qt version of uhd\_fft. But I didn’t want to add  
code to the generated .py file. This lead to the creation of a ‘Catch  
Function Result’ block. It is a pure xml block which calls another  
blocks  
member function and stores the result into its own variable. I didn’t  
want  
to use ‘Function Probe’ because I don’t want to spawn a new thread which  
constantly calls a function.

For those of you who are eager to try those blocks. The uhd\_fft\_qt  
flowgraph can be found in the projects examples folder.

In the hope that those blocks are helpful for others.  
Johannes

[1] [GitHub - jdemel/gr-misc: Useful blocks for various purposes. Currently mainly Qt GUI sinks and some blocks which are converted from GR 3.6 API](https://github.com/jdemel/gr-misc)

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**Author:** ![jdejong](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/j/a9a28c/32.png) [@jdejong](https://www.ruby-forum.com/u/jdejong)\
**Post date:** [December 19, 2013, 11:01am UTC](https://www.ruby-forum.com/t/new-qt-blocks-and-other-helpful-blocks/238130/2 "2013-12-19T11:01:52Z")

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Johannes

Just tried installing your helpful QT blocks. When I try the run  
qt\_block\_test.grc I get the following error;

File “/usr/local/lib/python2.7/dist-packages/misc/missile\_launcher.py”,  
line 28, in   
import usb.core  
ImportError: No module named core

I have got python-usb (0.4.3-1) installed. Any idea what may be wrong?

Linux Mint 16  
GNURADIO 3.7.2

Regards

Eddie