Funny PedalBoxes for Zynthian (using extra switches!)

It’s Thanksgiving weekend here in Canada. Still stuffed with turkey, Brussels-sprouts and pumpkin pie, I’d like to give thanks to this wonderful community! Not being a coder, I thought that I coud give back by designing some boxes. Inspired by the extra switches by @Fitz, I’ve built a Zynthian branded switch box and a sustain pedal. The build is tested and functional, but alas, @wyleu, I have yet to create a sound sample.

I have tried to keep the build as simple as possible. The pedal was modeled after an old Yamaha pedal I have. The first version used a tact switch which proved to be very noisy as the box became a resonator producing a very audible click when the switch was tripped. The second version uses mains wiring for the momentary switch. Not having a spring handy, I used IC packing foam for the spring return. Seems to work quite well. As a pal of mine would say: “cheap and dirty!”

The switch box is very simple. No big explanation here. I kept the box as short as possible. The wires are soldered at right angles to the terminals of the foot switches because the nine terminal ends butt right up against the box bottom, thus providing support for the switch. One issue I’m assuming, however, is that the switch state is unknown at startup. A simple LED for each foot switch would be nice, but then the box would require a power source. There currently is none in the box. I suppose that would be ok. Any suggestions here?

I’d be very happy to post the laser cut files and a bill of material on the Zynthian github site. I just need to figure out how that is done (@jofemodo?).

Any comments or suggestions for improvement would be appreciated! Reversing the positions of the 5 pin DIN and the TRS jacks might be a good start. Then I could use a short patch cable to connect the box and pedal without the wire to the DIN connector being in the way.

P.S. I still haven’t remade my Zynthian faceplate so it still upsidedown and my knobs never arrived :sob:
But I do have plans to design and 3D print some (Zynthian logo branded, of course!)


Hi @wolfpaw98!

I splited to a new thread. Your nice creations have enough merit for it … :wink:
Congratulations, my friend!! I’m really impressed with your work. I specially love the sustain pedal… ohhh yessss!

Regarding the sharing of the laser-cutter files, i think you should create several github projects and include all the documentation you have for every pedal. If you want, i can do it inside zynthian organization and give you permissions. Let me know if you agree with that and i will do it ASAP …

Regarding your knobs … please, refresh my mind and i will amend my fault :flushed:

Ahhh! For public information, this thread comes from:


That’s fantastic !! it also matches my latest order from Amazon that provide a similar functionality via the USB port using keypresses !!

It’s still on the boat from China, so we will provide a comparison shortly!

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Thanks for the compliments! Whoo hoo! I’m on a roll this morning! Now my Zynthian also has laser cut knobs!

I’ll post these too, along with the box and pedal build files.
@jofemodo, my Zynth is a home-build. No mistake by you (just a pile of praise from me to you for this awesome project!). The knobs I ordered never made it from China. I like my new custom ones much better!


Ohhhh! This is really cool too! Congrats!

Regarding the laser-cuter files, perhaps it would be OK to put alltogether in the zynthian-case repository. You can “fork + pull-request”.


I have to say when I saw @wolfpaw98 superb effort, I got goosebumps. The very thought that a community can work in this fashion is uplifting in a way that, few things have made me feel over the years. To imagine that someone recognises the brilliance of the overall concept and how Open Source can develop such a concept is fantastic! Congratulations all round… :star_struck::star_struck:

Now where’s my sound sample … ? :face_with_monocle:


Momentary Switches does solve the initial state debate but, we have mentioned the concept of a Bipolar CUIA element probably would resolve that.

The great thing we have here is a declared interface and it’s fascinating to see how it grows… I decided against the 1/0 option on zynthian-alm.local simply because of all the extra mechanical work required to get the functionality.

The LED route also lends itself to USB implementation simple because you do get the Power Supply for free! All your connectors are already done for you, but to provide both as the zynth does in it’s normal form is wonderful! The ability to solve a specific functional problem throu’ a choice of hardware implementations. . . . :slight_smile:

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Hi @wolfpaw98!

I’ve updated the wiki section adding some photos of your build:

Please, feel free to complete the text as you want. If you have not a wiki account, ask me for one :wink:


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Posted the files and instructions for the sustain pedal on github here:

I’ll post the switch box files soon.


Wonderful @wolfpaw98!

Thanks a lot for sharing!!

Finally got around to posting the files and instructions for the switch box as well!

I’m also working on an expression pedal. This one has one pot like the Yamaha FC-7, but I’d like to modify it to have a minimum volume pot as well like the Roland EV-5. Are the pins on the MCP 23017 only binary, or can they be modified to accept analog signals like from a pot?

IMG_7344 IMG_1378 IMG_3849 IMG_1406%202


You rather enjoyed making that didn’t you? … :smile:


Ohhh! What a beautiful pedal, my friend!
Regarding the MCP23017, it’s a pure digital GPIO expander. No analog inputs.
What you can do is using an ADS1115 module connected to the I2C pins. The new Zynaptik module (v3) allows to “plug” this module directly, but if you have a v2, you should find the way of hacking it. I would suggest using the Piscreen’s 26-pin connector footprint, that is currently unsoldered.

The ADS1115 is not currently integrated with zynthian software, but i’m working on it, so it will be working very soon :wink:



Thanks for the info @jofemodo! I bought an ADS1115 a while back when it was first mentioned and checked out the schematic. I’ll figure out a way to connect it to my original V2 board. Shouldn’t be too hard. Looking forward to the software update.

In the mean time, I’ll try connecting my new pedal to the Zynth with my PedalinoMini over WiFi. There’s a schematic there for 6 different pedal types. I plan to build one of each, because as @wyleu noticed, I do rather enjoy the making part :grin: :+1::man_dancing: My laser cutter rocks (almost as much as my Zynth!)!