External LED (WS2812B) and Qi charging deck

Firmware/software/electronics/mechanics
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t.yoneda
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External LED (WS2812B) and Qi charging deck

Post by t.yoneda »

Hi!

I tried to use the extended LED created in this topic with the Qi Battery charger.
When I tried to charge the battery, the LED started blinking irregularly.
Is this expected behavior? Also, is there any way to fix this behavior?

The pins do not seem to be interfering on this page (Expansion decks of the Crazyflie 2.X)

video: https://drive.google.com/file/d/1RkpAiS ... sp=sharing
DSC_0098.png
tobias
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Re: External LED (WS2812B) and Qi charging deck

Post by tobias »

This is a setup we have never tried as the LED-ring and Qi normally can't be mounted at the same time.

As you say, it should work but apparently some interference or similar is making its way though. Is the behavior the same if you charge using USB, I guess not?
t.yoneda
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Re: External LED (WS2812B) and Qi charging deck

Post by t.yoneda »

yes
when charging via USB, it blinks irregularly as well
tobias
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Re: External LED (WS2812B) and Qi charging deck

Post by tobias »

I guess you don't have a LED-ring to compare too? The LED-ring has a DC/DC step up/down to generate 3.7V for the LEDs and I guess this acts as a filter for VCOM. Try adding some capacitance between VCOM and GND, maybe that will help.

It could also be that VCOM becomes 5V during charging and the WS2812B signal is 3V. Possibly the WS2812B LEDs have a hard time interpreting the signal.
t.yoneda
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Posts: 27
Joined: Mon May 17, 2021 3:03 am

Re: External LED (WS2812B) and Qi charging deck

Post by t.yoneda »

thanks tobias!

when I charged the battery via USB with the LED ring, the LED ring lit up correctly
and I will try to add some capacitance between VCOM and GND
I will post results later
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