testing if one key of the keyboard is pressed

[Brainiac91]

Hi everyone,

As is montionned in the subject, i want to test if a specefic key of the keyboard is pressed, for example i want to know if the key "A" is pressed or "Z" or "3" ?? 

can anyone help with this please

Best regards

[aputman · Accepted solution]

Use an event structure, similar to this. 

[Alexander_Sobolev]

Option 1: 

Labview event structure, register event for This VI -> Key down. Then check by ascii code.

Option 2: 

Check  keyboard using Connectivity -> Input device control > Initialize keyboard function and Acquire input data function.

I use 2 if I need to check once, or to verify button is still pressed, because event is registered for VI, so if it is not in focus, it will skip it.

[Brainiac91]

thks aputman for the solution it works perfectelly, but there is a little issue, i want that the booleen turns to false when i release the key, or it turns automatically to false after a bit of time, is that possible ??

[GerdW]

Hi Brainiac,

did you play a little bit with this event structure?

Did you notice the "key release" event?

Simple pseudocode:

ON EVENT(key release) DO boolean := FALSE

[Brainiac91]

Hi GerdW,

In fact it is my first time using the event structure, but i found a soluion for the problem, it can be handled with the timeout event, thnks for answering anyway 😉

[aputman]

I wouldn't recommend putting the key up detection in the timeout case.  What happens if you decide you want to make the timeout longer for some reason?  There is a specific event, as Gerd suggested, for detecting when the key is released.  Use it.