Random On LED, manual off, and time between

[siruami]

Hi all.

I am completely new to LabView, I have version 8.5. I am trying to desing a VI that will measure reaction times given a visual stimulus, so I though in big LED that will turn on randomly, like every 2-4 seconds, but random and then the user will turn it off with one button.

I have been playing with the random numbers, loops, LEDs, shift register, etc... and I have some pieces but can't get to what I want which is what I have stated above, so I will appreciate your help a lot.

The Idea is so simple, once the VI starts, a LED will turn on randomly between 2 to 4 seconds between each blink, but when it turns on, I want the user to turn it off by pressing a button, once the button is pressed the random timer (2 to 4 seconds) starts again until the LED turns on again and the user turns it off and like that continuously for a number of times, I think I can resolve the total number of times this will run, add time stamps from the time blinks to the button is pressed and measure time, add a start button and everything else, I am just stuck with this of the LED turning on and off.

Thanks in advance for your help.

Again: version 8.5, thanks.

[jcarmody]

This sounds like a job for a State Machine. It could be more easily accomplished with local variables and Sequence Structures, but I get hives when I use them.

This'll give you your 2-4 second wait. A better State Machine would have a mechanism to wait that doesn't freeze the program until the delay finishes, but you can do that later.

See if this helps and post back.

wait.vi

[hooovahh]

A better State Machine would have a mechanism to wait that doesn't freeze the program until the delay finishes, but you can do that later.

I think this is an important feature, because right now if I press OK before the light turns on, then when the light does turn on, it immediately thinks I pressed the OK button and will register a reaction time of 0ms.

A solution I think might be easier is replace the Time Delay, with a while loop that waits based on tick counts. Then in the while loop you can pole the OK button, and if it is pressed before the wait time is reached a dialog can pop up and say they were too early.

[asbo]

My first thought was an Event Case with a random timeout (2-4s) with an event for the button which will catch pre-mature clicks. After that, a second event case with the current tick count wired into it with, again, a case for the button, with no timeout which will calculate the reaction time. Wrap the whole thing in a while loop or just use run continuously. Adding a reaction time history is trivial, either way.

[siruami]

I agree with hooovahh because I actually need that feature, I will try to add it myself first after all this good thoughts you guys have shared with me and I do appreciate them.

Thanks for the VI jcarmody, with my short experience in labview this is gold for me, I think I wont figure it out by myself in weeks, maybe months.

I will review and modify to my needs and post back as soon as I can.

Thanks a lot, I really appreciate you guys thoughts and help.

[zythum]

I agree with hooovahh because I actually need that feature, I will try to add it myself first after all this good thoughts you guys have shared with me and I do appreciate them.

Thanks for the VI jcarmody, with my short experience in labview this is gold for me, I think I wont figure it out by myself in weeks, maybe months.

I will review and modify to my needs and post back as soon as I can.

Thanks a lot, I really appreciate you guys thoughts and help.

Just disable the "stop" button (not gray) and reactive-it when LED On

[hooovahh]

Just disable the "stop" button (not gray) and reactive-it when LED On

That's probably the best solution, I just wanted a way to penalize the user if they click too early. I suppose you could still do that with a mouse down event when grayed out.