Building a keyboard slider that works online

Builder
1

OS (Win10):
PsychoPy version (v2021.1.4):
What are you trying to achieve?:
Trying to build a slider whose marker moves with arrow keys and people can select their answer with the RETURN key.

What did you try to make it work?:
Followed the solution provided by @jon here: Rating scale reponse failure via keyboard

if slider_kbControl.markerPos is None:
    # sets to our first position (or a random number?)
    # and makes marker visible
    slider_kbControl.markerPos = 3

#check keys (just the ones we want)
keysPressed = defaultKeyboard.getKeys(['left', 'right', 'return'])
for key in keysPressed:
    if key == 'left':
        slider_kbControl.markerPos -= 0.5  # subtract 0.5
    elif key == 'right':
        slider_kbControl.markerPos += 0.5  # add 0.5
    elif key == 'return':
        # confirm rating by setting to current markerPos
        slider_kbControl.rating= slider_kbControl.markerPos

What specifically went wrong when you tried that?:
The slider does not work ONLINE. No marker is shown and the keyboard method for responding is not working. The response is recorded (and the routine ends) only when a mouse click happens.

2

Have a look at my interactive slider demo which works with arrow keys and mouse hover.

3

Hi @wakecarter, thanks for the quick reply. I’ve had a look at your demo, but unfortunately, I get some errors concerning “slider_granularity” being not defined (I’ve basically copy-pasted your codes in my experiment.

Also, did I get it right that I just need one of the two routines in your demo (trial or iSlide)?

Sorry, I’m new to PsychoPy, and I’m really trying everything I can to make it work.

Cheers

4

You also need the contents of the start routine. However, you do only need trial or iSlider.

5

Yes, I’ve also included the contents of the start routine, that is why I don’t know what is going on. But if that is the only solution, I will try again. I might be doing something in the wrong way.

Thank you.

6

Check that slider_granularity is set in Begin Experiment in a code component that is either above the slider or in an earlier routine.

7

Thank you @wakecarter, that was it!

I also just discovered that the online experiments only work with the UK keyboard (not the Italian one, as left and right keys correspond to up and down). Probably that’s why I wasn’t able to make it work with all the material I previously found on this forum.

Thank you again!

8

If the issue is that left is up and right is down on an Italian keyboard you can always code it for both eventualities.

9

Yes, I will try and do that, thank you :slight_smile: