Trellis M4 open source grid controller

I’ve been working on a few projects for Adafruit using the Trellis M4, and thought people here may like to check it out. It’s an open source 8x4 button grid with RGB LEDs so, unlike the original Trellis, you aren’t stuck with just one color and loads of soldering anymore. Also, the microcontroller (ATSAMD51 M4) is built onboard, as well as an accelerometer (which I’ve been using for highly dramatic filter sweeps and pitch bends).


We’ve got Arduino and CircuitPython both running on it, sending USB MIDI and serial MIDI over the UART port.

To do synthesis or sample playback on it, we ported Paul Stofreggen’s amazing Audio library from Teensy over to it as well.

Here are the tutorials we’ve made so far, including a neat Arpeggiator Collin Cunningham just wrote inspired by Polygomé. I’d love to see what people here make of it/make with it.

I don’t have an Ansible yet, but I’m hoping to get one to see how I could better integrate Trellis M4 into my modular setup. Right now I’m using a Deopfer Dark Cloud to go Trellis M4 > DIN-5 MIDI > CV & Gate.


Cool and cheap one ! Thanks for the info

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@jedgar Looks cool! Do you know if/when kits will be back in stock?

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We’ll have another batch in stock pretty soon, I’m not sure of the exact date. There are also some AdaBox 010 subs still available, and without explicitly revealing the contents, it’s probably a good one to get if you want a Trellis M4…

A batch is in stock right now.

Just grabbed one of these! It looks very promising. There’s a simple tutorial on integrating the pjrc audio library

The workflow reminds me a bit of Axoloti, with a few extra steps. The neo-pixels are extremely bright and very responsive. The conductive pads seem a bit finicky, sometimes activating rows.

I like it so far! Although I’ve only played around with some demos. I feel like you could easily elaborate on the platform too. A companion board with an OLED and encoder like the Zoia would be killer.


Good to hear – one tip I have on the buttons is to add another layer of laser cut acrylic on top and use longer screws to get the buttons more flush to the top surface. This seems to reduce the off-axis wobble of the elastomer pads and improves the feel. You could also add some spacers if you don’t have easy access to a laser.

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Would it be feasible to make these act as a grid controller similar to the things done with the untztrument?

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I think so. The closest thing so far is the MIDI mode of this arpeggiator:
@okyeron has done similar work with similar hardware in the past, so hoping he may be able to weigh in here.

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It’s next on my list when I’m back home :slight_smile:


Just finished my fates so I’m looking forward to a diy grids like controller that won’t break the bank :slight_smile:

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The M4 Neotrellis is 8*4, so you’d need a cluster of 4 to recreate a 128 Monome grid. @jedgar the 5 pin fin connectors on the side means the M4 Neotrellis is expandable like the older trellis boards? I guess you would just have to desolder some of the jacks to get it mounted flat.

Immediately having fun with this and Fates/Norns. Works great with some of the poly engines!

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Excellent! I tried it with a couple norns/Fates scripts too, it’s really fun.

As far as tiling them goes, yes, that’s how the side connectors are intended to work. You can tile up to 32 4x4 NeoTrellis driver boards on the I2C bus of the NeoTrellis M4 (the 8x4 one that includes the microcontroller). Here’s a forum post of someone who added two of the 4x4 driver boards to a NeoTrellis M4:

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Only problem (for me) is the Arduino code won’t work out of the box for this. (The m4 and neotrellis code libs are different)

That forum example is with circuit python I believe.

Yes, great point – it seems the more direct approach so only one NeoTrellis library is needed is Feather M4 as microcontroller, and all the pads are w the 4x4 NeoTrellis driver boards.

Here’s an 8x8 bundle, but for 16x8 you’d need to adapt the laser cutting files.

Wow I’d love a 16x8 version…

Can you get these things directly in Europe, or do we have to import?

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Quick jam with the Arp Demo (sorry for quality) NeoTrellis script modified for hold mode which is a polygomé-esque sequencer. Swapped the Neo-Pixel colours around to match my Fates :grin: Using Passersby which is wonderful. Very neat combination!


20 characters of Yes, I love that!