Using skipUntil

[ReemyAliNasser]

Hi,
I am trying to use skipUntil until a specific flow is performed, I succeeded skipping the specified flow but it sounds it is skipped all the time, tried to add condition node but it is also not working

thanks

[bruno-f-cruz]

Heya.
Please add more information of what you are tring to achieve and, ideally, your current bonsai workflow. Thanks!

[ReemyAliNasser]

Hi,
I am trying to detect an object inside a specific region and once it is detected I want to send a specific stimuli to its coordinates

thanks

[ReemyAliNasser]

I solve it using SelectMany, but would like to know if I used SkipUntil in the correct way, thanks.

[banchan86]

Hi @ReemyAliNasser its still a bit hard to tell what your workflow is doing, but SkipUntil only triggers once, which I think might be a problem for the experiment logic you want to achieve (I presume you want to send a specific stimuli repeatedly everytime the object enters the coordinates right?)

Some other general tips:

• If you notice, the tracking pipeline (from Image-Grayscale to Centroid) is repeated twice. You can probably simplify the workflow by frontloading the common bits of the workflow that can be shared (such as this tracking), and then only start branching when you need to implement the conditional logic or some other processing step. This also makes the workflow easier to read.
• The last Zip might be problematic as well, you should only Zip when the number of items being zipped are equal (such as items coming out from processing). In that particular instance, you Zip some centroids from skipped frames together with cropped frames from camera (that have not been skipped) so the number of items will be unequal and the buffer size (memory usage) will grow.

[ReemyAliNasser]

Hi,
Yes, I am trying to give a stimuli each time the animal is entering a specified ROI.
Still, although I used SelectMany node with condition, now the stimuli is repeatable as long as the animal is inside the ROI but I want one stimuli per entrance, I would like to help me with that.

Thanks for the tips! I am new using Bonsai, the more I use it, the more I found shorter flows.

[banchan86]

@ReemyAliNasser No worries, glad you are using and learning more about Bonsai! Upload a zip file of your latest workflow as outlined by the instructions here if you need more help.

[ReemyAliNasser]

I could not find any information in the link you provide on how to upload my workflow

[banchan86]

@ReemyAliNasser fixed the broken link! It's pretty simple, compress the files to a zip folder and add it as an attachment in this GitHub.

[ReemyAliNasser]

I fixed it using this flow

but the problem is that if the animal exits the ROI very slowly it could detect it as entering again, maybe you have some solutions to fix this this problem?

thanks!

[banchan86]

Hi @ReemyAliNasser it is a bit hard to troubleshoot your workflow based on just screenshots, please attach your full workflow in a compressed zip file.

[ReemyAliNasser]

new_flow.zip
Hi, attached

[banchan86]

Hi @ReemyAliNasser its still a bit hard to follow the workflow, for instance I am not sure what you are trying to achieve with this section:

Maybe you can explain more what the intended logic is here?

If you just want to send one value when the condition changes, its better to use DistinctUntilChanged, and you can use GateInterval to add a "refractory" period after it exits or enters. You might need to switch the position of the Condition and GateInterval in this example below depending on what you need.

edit: Wanted to add an important note about the GateInterval operator, it operates on a master timer that is distinct from when the change is detected, meaning the gate opens every 5 seconds regardless of when the last element was sent out. This can help to reduce the number of false positives, but to achieve a true "refractory period" will be harder.