Updating the docs - hope this is allowed / correct

Developers
1

Hi team,

Thanks for a great piece of software.

I’ve been playing about with Klipper and neopixels and after a few hours finally came to understand that they are not supported on the Linux MCU / Raspi. To save others the same journey I have edited the docs to reflect this. I hope this is ok and that I’ve done it correctly - first time using Github and ‘pull requests’ and the like are all new to me. If I’ve missed something important please let me know.

Cheers Martin.

2

I haven’t tried them myself but they are pretty particular about their timing and voltages so it does not surprise me that they would not work. I will do some testing of this myself when I eventually get around to reviewing the PR.

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3

This is where I got the info that it doesn’t work from Klipper Github issue.

Cheers.

4

The question is, will it work with a Level shifter?

5

Sadly I have no idea what a ‘level shifter’ is - I’m at the ‘I know nothing stage’ but I’m happy to test stuff and update some docs and here and there, if that is at all useful?

6

Neopixel use a Signal line, the Signal musst have 5v or so, the rpi gpio use 3.3 v
A Level shifter pushes the Signal 3.3v to 5 v

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7

Note :
You can also use One pixel as a Level Shifter. Use one dot as near as Possible to the pwm gpio on your RPI, this is called a 0 Pixel, this pixel has no use on lightning only on shifting.

8

Neopixels work pretty well a t 3.3V so I don’t think that is the issue.

9

its becouse klipper use bitbanging on the pi and not the pwm channel

10

Pi Pico could be a great second mcu (because of documentation, availability and cost) for controlling neopixels, extra fans, temperature sensors, etc.

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11

This would still require a PCB with all the supporting hardware to add all this functionality. The Klipper Expander does exactly what you listed, but it uses a STM32F042. Perhaps the Voron team will create a revised version with the RP2040 since it’s generally less expensive and more readily available right now than STM chips.

12

It would be simple to make expansion board for PICO, however Pi PICO does not have all the software needed yet.