Bring back the groove to eurorack.

The Robaux SWT16 is a 16-track eurorack trigger sequencer with up to 16 steps per track.

Programmable like a classic TR machine, the SWT16 can be used not only for triggering drum sounds, but also for Envelopes, S'n'Hs or resetting LFOs.

The SWT16 is polymetric - each track can have a different length, from 1 to 16 steps. Even more complex rhythms succeed with the individual clock divider per track.

The SWT16 has an intuitive user interface. All operation is via the illuminated 4x4 keypad. From the main screen, you can access the 16 different modes of the sequencer. The buttons adapt to the selected mode. With the back button, you can quickly return to the main screen.

Each track has its own trigger output. In addition, the triggers are also sent via MIDI notes (requires an adapter).

More Demos?


Choose a mode you want to learn more about. Click on one of the 16 buttons to see which mode is behind it.

Length Reset

In step mode, you can program your trigger tracks like a classic drum computer. Select the track you want to edit by pressing one of the 16 buttons. Then you can set the steps to create your patterns or override the steps.


In Tap mode, you can program your patterns on the fly. Each of the 16 keys represents one track. Play the keys while the sequencer is running to program your pattern.


In this mode, you can fill the sequencer memory with random patterns. Each button represents a track. Pressing a track button replaces the tracks current pattern with a random pattern.


If you want to delete a track, you can clear all steps in your pattern in this mode. Each button represents a track. Press the corresponding button to delete the pattern.


This mode combines many modes into one. Perfect for live situations. Here you have access to four tracks at once. Each column represents one track.

Mode A

The first line mutes a track. Press 1-4 to mute the corresponding tracks.

In the second line, you can temporarily replace the pattern with continuous triggers. Perfect for adding drum rolls.

The third line changes from mode A to mode B or vice versa for each track.

Mode B

In mode B, the first line becomes a tap mode, where you can program your patterns on the fly.

Did you miss a beat? You can simply delete the track in mode B from the button in the second row and then play it again.


In this mode, you can mute your tracks and unmute them. Each of the 16 buttons represents a trigger track that can be activated or deactivated by pressing.


In this mode, you can add continuous triggers. Each of the 16 keys represents a trigger track. Hold down the corresponding key to temporarily replace the current pattern with continuous triggers.


In this mode, you can invert the programmed triggers for each track. Each of the 16 keys represents a trigger track. Hold the corresponding button to invert the triggers.


In this mode, you can set the length of each track individually. Select a track by pressing the corresponding button. Then you can adjust the length by pressing one of the 16 buttons to set the step length. The 5 button sets the length to 5 steps, the 12 button to 12 steps and so on.

Length Reset

Too many polyrhythms? Activating the length reset restarts the pattern every first step of the master clock. For example, a 5-step pattern is played 3.2 times in a beat. Each of the 16 keys represents a trigger track. To toggle the length reset, select or deselect one of them.


In this mode, you can choose to combine two or more consecutive steps into one long gate or retrigger them at each step. Press the corresponding button to select the retrigger behavior. When it lights up, it fires again. When the button is off, the triggers are combined into a gate.


By default, each trigger track fires when it reaches a new clock signal. By setting the clock divider for each track, you can extend your patterns up to 16 steps to the master clock.

Select a track by pressing the corresponding button. Then you can adjust the division by pressing one of the 16 buttons. Knob 1 means that it is in sync with the master clock, button 4 divides the clock by four and so on.


By default, the sequencer requires a clock signal to operate. It is also possible to use it as a standalone sequencer. In autoclock mode, you can switch between internal and external clock.

Select one of the buttons in the bottom lines to switch between internal and external clock.

When the buttons in the lower left corner light up, the autoclock is enabled.

If the buttons in the lower right corner are lit, Autoclock is disabled and you need to trigger the sequencer with an external clock.

If the auto clock is activated, you can control the internal clock of the sequencer. Press the 1 button to start and stop the sequencer. Press the 2 button to reset the sequencer while it is playing. Button 3 and 4 is used for speed control. Decrease the clock tempo by pressing the 3 button and increase it by pressing the 4 button.


The triggers are also sent via midi. You can choose for each track which Midi channel should send these triggers. Select a track by pressing the corresponding button. Then you can adjust the midi channel by pressing one of the 16 buttons. So buttons 3 set it to channel 3, buttons 8 set it to channel 8 and so on.


There you can save all your current patterns and settings in the memory of the sequencer.


In util mode, you can enable and disable functions of the sequencer.

Disable animations

Press the 1 button to enable/disable the animations that will be displayed when entering a new mode. But nobody really wants that.

Flip module

You want to turn the module upside down? Activate the flip mode by pressing the 2 button so that the jacks and buttons are in the correct order.

Do it yourself.

The SWT16 is based on Arduino Uno and a few more electrical parts you´ll get from your local electronics store. A complete kit will be released soon, making it even easier to build the device.

Open Source

Since the sequencer is based on Arduino, you can easily change the firmware, add or remove features. This allows you to use the machines in a completely different way. For example to play minesweeper.


Download the manual.

Assembly Guide

Download the assembly guide.

Circuit Diagram

Download the schematic.

Additional Parts

Comming soon...

3D Printed Parts

The sequencer uses custom parts that need to be 3D-printed. The button holder and the front panel can be found here on Thingiverse. You can also make a aluminum front panel from this file.

Firmware & Updates

Comming soon...


Why isn't there a dedicated button for this and an additional button for that?

In eurorack, all that matters is to save space for even more modules. That's why the interface is reduced to the essentials. On 14 HP, you get alunchbox-friendly 16 track sequencer with an intuitive interface that gives easy access to all functions. But it is certainly a complex machine.

I cannot reach the buttons because the cables hang over the pads. Why are the jacks on the bottom of the module?

In some (eurorack)-cases, the cables are in the way. Just flip the module over and enable flip module in the Util mode.

I only need 8 tracks.

The more tracks you have, the better. Give it a try - once you have looked at all the options, you want to own two or more devices.

Why is there only 16 steps per track - I need more!

Sure, you only have 16 steps per track. You can create longer patterns that match the master clock by editing the clock divider for each track. Use a different track to program triggers and combine them with an external trigger combiner module. Set the step length to an odd number to get more variations.

Is there latency?

Yes. Since it is based on Arduino, there is a latency of about 5 ms. Workaround: Let SWT16 be your clock master. Just use a trigger track to sync your other funky sequencer modules and Robaux your uncle.

Are you kidding me? This is a simple Shift Out Circuit from Arduino beginner lessons.

Right. Sometimes things are not hard - but software related.



Number of Tracks: 16

Number of Steps per Track: up to 16


1 x Clock In

1 x Reset In


16 x Trigger Out

1 x MIDI Out

User interface

16 x backlight silicon button pads

1 x Illuminated push button


Width: 14HP

Requires a ±12V eurorack supply or usb power.