MATLAB Answers


Create a block to read keyboard inputs

Asked by Raju Purohit on 17 Jun 2011
Latest activity Edited by John Kelly on 26 Feb 2015
I want to create a block in simulink which prompts me to enter a key & reads ASCII values from keyboard while running a simulation. Input to the block is through keyboard & output is its ASCII value.
I think this can be done either in S-function or embedded matlab function blocks. But I dont know how to use these blocks.
Can someone help???


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2 Answers

Answer by Fangjun Jiang
on 17 Jun 2011
 Accepted Answer

Drag and drop a Constant block, right click it, select "Block Properties ...", click the "Callbacks" tab, select "OpenFcn", type in the following line,
set(gcbh,'Value',num2str(double(input('Press a key: ','s'))));
Set your model simulation stop time to be inf and run the simulation, while the simulation is running, double click the Constant block, switch to Command window, press a key, observe the output value of the Constant block.


That was helpful to some extent. I am basically trying to model (3D model using VRML) a block which should move right when I press right arrow key, move up when i press up arrow key and so on. I need to continuously feed the input through keyboard.
Then, a MATLAB Fcn block would do it. Type in double(input('press a key','s')); in it and run the simulation. Keep in mind though, that this will ask you for a key input every simulation step. I tried a simple example and the value output is right. Not sure how the rest of your model would work with it.

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Answer by Kaustubha Govind on 17 Jun 2011
Edited by John Kelly on 26 Feb 2015

The Embedded MATLAB Fcn block should be sufficient for your purpose. You can use the input function to read inputs from the keyboard.
Here is an example using the Embedded MATLAB Block: Creating an Example Model That Uses a MATLAB Function Block.


Actually Embedded MATLAB Block does not support input function.
You can use eml.extrinsic to call functions unsupported for code generation.

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