pi-Stomp! A build-it-yourself modep pedal is now available

I’ve been a fan of modep for a while. I wanted to use it as a rugged pedal with footswitches, knobs and an LCD. So about a year ago, I built a prototype and shared it with some friends who suggested that I make it available to more people. After many prototypes, I have it all ready for others to build. You just need to be decent at soldering.

It looks like this when finished:

I’ve set up a website, parts store, wiki and github all accessible from here:


The latest version has been successfully built 3 times. Two additional builders have parts and will start soon. I’m hoping to have 7 additional builders build it before marketing it wider. I thought this would be a good place to start :wink:

Feel free to ask questions here or email at support@treefallsound.com

Thanks Blokaslabs and Mod Devices for making it possible!


I just went through your docs and WOW. I appreciate the amount of time and effort that you put into this. I have been wanting to do something like this for a while, but my EE and python skills are not up to snuff. When I get some more time I would love to start building this.

I see that the forums are coming. Do you have a discord setup?

Also, would you recommend the raspberry pi 4 over the 3?


Congratulations on your project, looks great! :slight_smile:

Thanks! Yeah, it’s been quite the fun, challenging and time consuming project.

I will setup a forum on treefallsound.com soon. In the meantime, there is a fairly active thread on the only other forum that I posted to:

The Raspberry pi 3 A+ was chosen because of its form factor. The “B” form factor used by the pi-4 wouldn’t fit in the enclosure - extended length and depth due to the array of hardware ports not used by pi-Stomp. If they ever create an pi-4 A+, then absolutely.

That said, the quad-core power of the pi-3 A+ is quite sufficient for most pedalboards. I can run up to 7 or 8 effects just fine at 96kHz (128 or 256 frames), and have ran up to 14 effects at 48kHz.


… oh and, there is no requirement of python skills to use pi-Stomp. No programming at all, you just need to be able to ssh to the Pi to run the setup scripts (which installs modep, downloads LV2 plugins, downloads/installs dependent libs, etc.)

Building the hardware does require decent pad soldering skills. The key being enough fully flowed solder for a good joint, but definitely not too much, as most of the pads are on 0.1" centers, which makes shorts somewhat more likely than with other “hobby” level projects. The physics of solder and flux are pretty amazing though. Once you get the hang of consistently doing a few dozen pads right (on a practice board), surface tension just moves solder where it needs to be over the pad and part lead. Again, the key is just Not Too much.

Adafruit has a great soldering guide here:


If you ever develop a solder free kit, I’m definitely interested. Unfortunately I have no possibility to solder anything atm, so I have to pass it. :frowning: But will keep an eye on this one. Looks really cool! :+1:

Thanks Tomikoo. If I was to offer a “solder free kit”, it might as well be a finished product because the final assembly only takes about 5 minutes (for me, maybe 10 for you). There are logistics of selling a finished product that I just don’t have time for, and my mission all along has been to create a DIY pedal.

That said, I do a build myself every time I revise the board. Thus, I currently have 6 units with the last three being fully compatible with the published software/firmware. I need those 3 units for my development and demo’ing, but when I do make the next one, that “spare” fourth would likely be one I could sell as a finished product. That would not be for another month or two, but I’ll let you know.

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Yeah, definitely throw me a message, if you happen to have a spare one you could sell. Of course… where are you located, thinking about the shipping and possible customs, as I live in Europe? Those can sometimes be quite a nasty “extra” cost, if sent from outside Europe. But that said, definitely interested, if there’s ever such possibility. :slight_smile: Damn… starting to be interested even, if there wouldn’t be :smiley: But yeah, I’ll need to ask one friend of mine who can solder (have the equipment), if he could help me a little at some point. :slight_smile:

Sweet jesus - I need one of these kits!
I can’t wait until the end of the month ha ha

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This looks awesome thanks for all the work you put in.

Quick question regarding presets, how did you get this working with footswitches as I understand they aren’t midi mappable in modep?

Thanks. Correct. To my knowledge, presets (aka Snapshots) are not controllable via midi in Mod/modep. So I use an available API via REST:


Where N is the index of the desired preset/snapshot. A pedalboard with 4 presets will have corresponding id’s 0 thru 3

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This is extremely cool. Thanks for sharing all of the details!

For those interested, pi-Stomp bundles are back in stock.

There have been a few more community builds. I got some good feedback (no pun intended) which I’ve used to make the new boards somewhat easier to build (IC sockets and less soldering).

The main page is here: https://treefallsound.com

To direct link to the parts bundles is here: https://treefallsound.com/opencart/index.php?route=product/product&path=57&product_id=55

Just remember you also need to buy the Mouser BoM parts (link is on that last page). Everything is currently in stock (which hasn’t always been the case in the last few months). The total cost works out to $198 plus tax and shipping.

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