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2 layers55.9 × 98.8 mmEtc, the printed circuit board in 3D

Yottasynth is an under-development digital synthesizer. It is an open hardware project built around an ARM microcontroller, with custom hardware, 3D-printed parts, and ongoing firmware development.

Size
55.9 × 98.8 mm
Copper layers
2
Thickness
1.6 mm
Parts
8
Nets
66
Pads
98
Tracks, vias
76, 46
Pours
2
Routed
Yes
KiCad
KiCad 10.0 (file 20260206)
Created
10 Mar 2024
Updated
26 Oct 2026

Overview

Etc is an open-source printed circuit board by yottanami, from the yottanami/yottasynth repository on GitHub. It is a 2-layer board of 55.9 × 98.8 mm with 8 parts on 66 nets, routed with 76 tracks and 46 vias.

It is built around the TEENSY 4.1. Its parts include 2 ICs and 1 resistor. It belongs with the audio and music boards and the NXP (LPC, Kinetis, i.MX RT) boards of this library.

Main components

1

README

README.md

Yottasynth: Open Hardware Touchscreen Synth with Persian/Iranian Tunings

Yottasynth is an open hardware touchscreen synth with a compact page-based control surface, five context-sensitive knobs, an arpeggiator, a step sequencer, and support for Persian/Iranian music tunings.

یوتاسینث یک سینت‌سایزر دیجیتال متن‌باز با رابط لمسی، سکوئنسر، آرپژیاتور و پشتیبانی از کوک‌های موسیقی ایرانی است. این ساز امکان انتخاب کوک‌های مرتبط با دستگاه‌ها و آوازهای ایرانی را فراهم می‌کند تا برای اجرا و طراحی صدا در فضای موسیقی ایرانی مناسب‌تر باشد.

Yottasynth prototype Yottasynth board

What It Is

The current firmware is a playable mono synth instrument with:

  • a touch-first panel UI
  • five context-sensitive knobs
  • arpeggiator
  • 16-step sequencer
  • three effect modes: Echo, Reverb, and Drive
  • selectable Persian scale tunings

Current Features

  • PLAY, OSC, FILT, MOD, FX, ARP, SEQ, and SET pages
  • mono synth voice with dual band-limited oscillators, noise, low-pass filter with a bipolar filter envelope, ADSR, glide, and LFO
  • page-specific touch actions and knob mappings
  • internal BPM transport, or external MIDI clock sync over USB
  • arpeggiator with mode, division, gate, octave range, and latch
  • 16-step sequencer with step selection, bank switching, swing, and live MIDI record
  • effect editing with page-dependent controls
  • output volume, tuning, and clock-source (internal / external) selection from the settings page
  • eight patch slots (sound, FX, arp, sequence, tempo) with SAVE / LOAD / INIT
  • Persian scale support through alternate tunings
  • touch screen used for navigation and OK / Confirm actions
  • boot splash with the YottaSynth wordmark and www.yottasynth.com while the synth starts up

Persian / Iranian Tunings

The current tuning list includes:

  • Standard (استاندارد)
  • Shur (شور)
  • Abuata (ابوعطا)
  • Dashti (دشتی)
  • Bayat-e Tork (بیات ترک)
  • Afshari (افشاری)
  • Segah (سه‌گاه)
  • Chahargah (چهارگاه)
  • Homayun (همایون)
  • Bayat-e Esfahan (بیات اصفهان)
  • Nava (نوا)
  • Mahur (ماهور)
  • Rast-Panjgah (راست‌پنجگاه)

How It Works

Yottasynth is organized as one compact panel split into pages. The touch screen is used to switch pages and trigger actions, while the five physical knobs always control the five parameters shown on screen for the current page.

In normal use, a MIDI controller feeds notes into the synth engine through USB host MIDI. You shape the sound on the synth pages, switch to ARP for rhythmic note patterns, use SEQ for step programming and live record, and adjust global volume or tuning in SET. When a destructive action needs confirmation, a second tap on the armed button acts as OK.

The transport (sequencer and arpeggiator) normally runs on its own internal BPM. Set SYNC to EXT on the SET page to slave it to an external MIDI clock over USB instead. Two USB paths are supported without any hardware change:

  • the USB host port (alongside the keyboard, through a USB hub) for standalone gear such as an Ableton Move
  • the native USB port (the same cable used to upload firmware) for a computer / DAW such as Ableton Live

In external mode the synth follows the host's tempo and its start / stop / continue transport.

Interface Summary

  • top bar: page title plus compact status
  • middle panel: parameter cards and touch actions
  • bottom bar: eight color-coded tabs

Page layout:

  • PLAY: quick performance controls
  • OSC: oscillator mix, noise, octave, detune, and waveform changes
  • FILT: filter cutoff, resonance, filter envelope depth, and ADSR shaping
  • MOD: LFO, bend range, and modulation target
  • FX: echo, reverb, or drive editing
  • ARP: arpeggiator setup
  • SEQ: 16-step sequencing
  • SET: output volume, tuning, clock source (internal / external sync), patch slots, and input test entry

User Guide

For a user-perspective walkthrough of the panel, controls, pages, and sequencing flow, see docs/user-guide.md.

For developer-facing documentation of the firmware structure and code, see:

Screenshots

Yottasynth interface overview

To export screenshots of the current screen pages without running the device firmware:

bash
python3 scripts/generate_screenshots.py

This writes one SVG per page, a stitched overview.svg for the README, and a simple preview index into docs/screenshots/.

Hardware + 3D

  • board design files: etc/board/
  • touch-driven panel firmware: src/
  • headers and shared definitions: include/
  • project docs: docs/

Status

This is still an active work-in-progress project, but the firmware already implements the main instrument shell and core performance workflow.

Contributing

Contributions are welcome. Feel free to open an issue or a PR if you want to help with firmware, hardware, or design.

Issues

https://github.com/yottanami/yottainst/issues/new

Contact

https://yottanami.com

Support

Parts

8
QtyValueFootprintReferences
5R_PotentiometerConnector_Molex:Molex_KK-254_AE-6410-03A_1x03_P2.54mm_VerticalRV1, RV2, RV3, RV4, RV5
1RResistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P2.54mm_VerticalR1
1TFT_320x240Connector_Molex:Molex_KK-254_AE-6410-14A_1x14_P2.54mm_VerticalU3
1Teensy4.1TEENAY:TeensyU1

Questions

How big is the Etc PCB?

It measures 55.9 × 98.8 mm and has 2 copper layers, 1.6 mm thick.

What parts does the Etc use?

8 parts, built around the TEENSY 4.1. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the Etc KiCad files?

From the yottanami/yottasynth repository on GitHub, at the commit this page was made from: the board is etc/board/board.kicad_pcb and its schematic etc/board/board.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the Etc design in my own project?

Its repository states no licence, so its author keeps all rights: ask yottanami before reusing the design.

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