LabVIEW for LEGO MINDSTORMS and LabVIEW for Education

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Detecting colors and signal duration. Is it possible?

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We still have problems with the retrieving part...


Still for some reason all the processed blocks shows up as brown and some random number alongside it...
We've tried the "retrieve now" button and it kind of triggered some movement in the retrieving motor, but not something corresponding to what value it should be... 


I'm starting to suspect there could be some old files(we have a lot now) or something jacked up in the system... maybe this makes some part of the system act wrongly.


Under i've added a text file trying to explain what happens with screenshots and also ALL the files that i've now placed in a "final" folder... I want the system to only communicate with these, but im not really sure how to replace the old VI's without getting lots of those red dots. (Program asks me when i run the main VI to locate all the older files) 


Would you be so kind to take a look at all these files, controll that they act somewhat correctly, and then connect them all to the Lego Sorter final version VI? 


I dont think lighting has something to do with the processed blocks beiing brown though as the only things here getting detected as brown, are the yellow bricks which was not used during these tests. Color detection works fine too in all other parts of the program 



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Message 51 of 97

I will have a check in 2 or three hours

Good that you added all vi's and I will control them next to my version.


If something is moving just a part of a second where it should move seconds it probably has a parallel control taking over. Race conditions are easy in LabVIEW.


I hope you have different motors selected in the separate while loops. The for loop only acts after both while loops so you can reuse a motor there if needed.

greetings from the Netherlands
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Message 52 of 97

Thanks for taking the time! 


And yes, we have 2 new motors acting as the retrieving part.  (Port C and D) 🙂 


1 for the conveyor belt and 1 for the arm... All separate 🙂 

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Message 53 of 97


I see one problem and saved a solution in the next files.

You should place all sub vi's and controls in one new folder that is at the same or lower folder level as the old vi's. (If at a higher level, LV will serach until it finds an old version.)

Then open the main vi (Lego Sorter 6 I called it now) and only point to new files.

If you get any red dots, just ignore them.


The problem was that you forgot to connect the lenght of a long block to connect to the sort engine.

So it took the old value 604 or something instead of the new value from the main vi.


I now have added all components in a zip file.

They are all you need.


greetings from the Netherlands
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Message 54 of 97

Fantastic! The processed blocks table now works 🙂 

We're taking the weekend "off" the project to get ahead on an upcoming exam in mathematics. 

Will be back testing again on Monday and hopefully then we can get the system to retrieve the right bricks


We'll keep you posted,


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Message 55 of 97

Hi Albert


Sorry for the lack of updates...

As I mentioned earlier, we have an upcoming exam in under a week now... We've decided to soly work on that until it's done at the 27th. 


The Lego project is due at the 7th of December, that's when we're going to present it. So we have some time after this exam to properly finish the project. 

You will hear from us again sometime inbetween these two dates.


As always, thanks 

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Message 56 of 97

good luck

greetings from the Netherlands
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Message 57 of 97

Thanks 🙂

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Message 58 of 97

Hi Albert. 

We're finally done with all prior exams and our project report. Now we have until Friday to make everything work 100%... So this is just a headsup that we probably will ask a few questions the coming days 🙂

Hope everything is good

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Message 59 of 97


I've left you a text file explaining some issues we have right now with the code, as well as a proposition for another execution of the retrieving system and the UI. We've been thinking of a much simpler way for ordering bricks. I've left the details in the doc. 



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Message 60 of 97