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LEGO version of Pixy for Arduino

Pixy LEGO
#1

Hello!

This project and product looks very interesting, I’m considering to buy for a school robotics project initially and later to use for my own project so have a few questions.

a) If I buy LEGO EV3/NXT version of Pixy how can I repurpose for using with Arduino?
b) Does the LEGO version allow to take custom actions (conditional branching) based on object detected? For example, if object A is detected rotate motor on port A, if object B is detected rotate motor B.
b) what is the required minimum lighting for it to detect object reasonably well and consistently?
c) what is the minimum and maximum distance the object can be for it to learn and detect?
d) how well can it differentiate and detect 3D objects?
e) I’m assuming it stores the information of learned object in Flash, how many objects can it remember to detect?

Thanks!

#2

Hello Raj,
You can use Pixy LEGO with arduino, you just need to make an arduino cable and switch to the “general” firmware.

Regarding the conditional branching – it doesn’t work as you describe. If you want your robot to do things conditionally, you should probably use a “switch” block in the Lego programming environment. Does that make sense?

Pixy can distinguish among 7 color signatures, which are stored in flash memory. In general, more lighting is better than less lighting. Pixy can work well in somewhat dim lighting though.

Hope this helps!

Edward

#3

OK, great. If we buy Arduino version and decides to connect to EV3, would you be able to sell the EV3 cable and/or share how it can be built by someone?

#4

Hello Raj,
I believe Robotshop will sell the LEGO Pixy cable, but you might email them and ask when they expect to start selling.

Regarding making a cable:

http://cmucam.org/projects/cmucam5/wiki/DIY_LEGO_cable

Hope this helps!

Edward

#5

I finally got my Pixy today and having challenges with it learning objects. Hope someone can help, else all my excitement for our school robotics team will go away. We would like it to learn a AA battery and a soda can. I can’t to get it to learn Kirkland brand AA battery. Any help to troubleshoot something I maybe doing wrong is much appreciated. If it helps I can do skype or call to troubleshoot live. We have a robotics meeting coming up in a couple of days.

#6

Hello Raj,
Batteries tend to be pretty shiny. Shiny can be challenging because the color becomes whatever is being reflected. You might try wrapping the batteries in something – some colored tape for example.

You might also try to teach Pixy some objects of uniform hue, to get a feel for what Pixy is good and not-so-good at detecting. Pixy can’t reliably detect everything, unfortunately. The hue of the object needs to be distinct. Black, white and reflecting (shiny) are not recommended.

You should also take a look here:

http://cmucam.org/projects/cmucam5/wiki/Some_Tips_on_Generating_Color_Signatures_2

Hope this helps!

Edward