pi-Stomp > Hacking pi-Stomp

RGB stomp switch led

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I recently got my hands on this project and had an idea but am struggling to figure out whether it's possible. I want to add led rings to the footswitches however I thought it would be cool if the led color could match the pedals color on screen. I found these ws2812B rings on Amazon https://a.co/d/hIDGDw3.

From the research I've done, I'm pretty certain I can grab 5v power and ground from the barrel jack and also give reference ground using the open GPIO header on the pi-stomp board. My issue is with which GPIO header to attach the D0 pin from the lights to. All tutorials I've found use GPIO 18 which is PWM0 but I noticed GPIO 13 is open which is PWM1.

If this will work electrically I have more faith in myself to figure out the code end of things.

Thanks for any help!

Randall (Admin):
Yes, it is possible to use WS28xx addressable LED's with pi-Stomp.  In fact, I just added support code for that recently and it will do exactly what you suggested, the color of an assigned footswitch would match the plugin category color.  Change to a pedalboard with different footswitch assignments and the color changes too, cool right?

To power WS28xx LED's, you'll almost for sure need 5v.  That's not available on the header, but if you avoided putting a C5 in place (as the instructions suggested), the round pad of C5 is +5v.

As you discovered, you'll also need a GPIO pin with PWM.  GPIO13 (pin33) is the one free GPIO on pi-stomp that has PWM support.  Fortunately, you only need just that one GPIO to control a whole string of WS28xx LED's.

The software support hasn't been merged to mainline yet.  To use the staging branch, stop and move aside your current pi-stomp install:
cd ~
mv pi-stomp pi-stomp0
git clone -b v2.1.1-staging https://github.com/TreeFallSound/pi-stomp.git

Edit ~/pi-stomp/pistomp/default_config.yml and replace “gpio_output" with ‘ledstrip_position” and give it the number of the pixel in your ledstrip (0 for the first, 1 for the second, etc.)



This sounds like an awesome addition - I'd be keen to add some spare ws2812 that I have to my pedal build.

Please can you let us know the timeline for integrating this and the next release?


Randall (Admin):
Cannot say exactly.   Some bug fixes and minor features like this in the queue, so probably by April.  I'll try to remember to post back on this tread about it.

Hi, did you include it in the new build?
I wanted to use some ws2812 to light up my buttons, but
when i change the config file its stuck on the pistomp loading screen.


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