2 layers213 × 65.1 mm
2 layers76.1 × 116.7 mm
Omsk
aroum/omsk21You can choose any one of the following encoder models:
- Size
- 76.1 × 116.7 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 88
- Nets
- 86
- Pads
- 386
- Tracks, vias
- 1,969, 30
- Routed
- Yes
- KiCad
- KiCad 9.0 (file 20241229)
- Created
- 7 Jul 2026
- Updated
- 3 Oct 2026
Overview
Omsk is an open-source printed circuit board by aroum, from the aroum/omsk repository on GitHub, published under the GPL-3.0 licence. It is a 2-layer board of 76.1 × 116.7 mm with 88 parts on 86 nets, routed with 1,969 tracks and 30 vias.
It is built around the NC7WZ16P6X, H11L1 and 1N4148W, with the PJ-313 and RP2040-ZERO among its other parts. Its parts include 39 diodes, 16 switches, 7 resistors, 5 capacitors and 5 connectors. It belongs with the RP2040 boards of this library.
Main components
5
NC7WZ16P6X
SC-70-6(SOT-363)-40℃~+125℃ 1 1.65V~5.5V 10uA 2 2.4ns@5V,50pF 32mA 32mA Power-off isolation、Level shifting TinyLogic Unidirectional SC-70-6(SOT-363) Buffers, Drivers, Receivers, Transceivers ROHSonsemiBuffers, Drivers, Receivers, Transceivers
H11L1
DIP-6-55℃~+100℃ 1 1.6mA 1Mbit/s 250mW 3V~15V 5kV DC DIP-6 Logic Output Optoisolators ROHSEverlight ElectronicsLogic Output Optoisolators
1N4148W
SOD-123150mA 1A 1V@50mA 1uA@75V 400mW 4ns 75V Independent SOD-123 Switching Diodes ROHSSTMicroelectronicsSwitching DiodesPJ-313
插件-25℃~+75℃ 24V 25mA 3.5mm Headphone Jack Phosphor Bronze 插件 Audio Connectors ROHSSOFNGAudio Connectors (Headphones)
RP2040-ZERO
-- Development Boards & Kits ROHSWaveshareDevelopment Boards & Kits
README
hardware/pcb/README.mdPCB
BOM
Basic
| name | pcs | type | package | position | description |
|---|---|---|---|---|---|
| 1N4148W | 17 | Diode | SOD-323 | D1 - D17 | keyboard matrix + MIDI |
| 100nF x7r 50v | 4 | Capacitor | 0805 | C1, C3, C4, C5 | MIDI jacks + PWM Audio |
| 47uF x7r 50v | 1 | Capacitor | 1210 | C2 | PWM audio |
| 10R for 3v3 or 220 Ohm for 5v out | 1 | Resistor | 0603 | R4 | MIDI jacks |
| 33R for 3v3 or 220 Ohm for 5v out | 1 | Resistor | 0603 | R3 | MIDI jacks |
| 100R | 1 | Resistor | 0603 | R6 | PWM audio |
| 220R | 2 | Resistor | 0603 | R1, R5 | PWM audio + MIDI jacks |
| 470R | 1 | Resistor | 0603 | R2 | MIDI jacks |
| 1.8k | 1 | Resistor | 0603 | R7 | PWM audio |
| PJ-313 (3 color) | 3 | jack sockets | THD | J2, J3, J4 | Audio + MIDI jacks |
| Alps EC12 8.5 mm | 4 | Encoder | THD | ROTENC1 - ROTENC4 | Encoder for more info view below |
| H11L1 SMD | 1 | Optocoupler | SOP-6 | U1 | MIDI jacks |
| Kailh choc sockets | 16 | Switch socket | SMD | SW1 - SW16 | keyboard |
| Kailh choc v2 | 16 | Switch | THD | SW1 - SW16 | keyboard |
| NC7WZ16P6X | 1 | IC | SC-70-6 | U2 | MIDI jacks + PWM audio |
| rp2040/rp2350 zero | 1 | MCU | Module | MCU1 | MCU (rp2350 recomended) |
| WS2812B MINI-E | 22 | RGB LED | 3228SMD | LED1 - LED22 | WS2812B MINI-E |
Encoders
You can choose any one of the following encoder models:
| name | torque | # of detent/pulses | description |
|---|---|---|---|
| EC12E1220301 | Standard 3 to 20mN･m | 12 | |
| EC12E1240301 | Lightest (jog) 3±2mN･m | 12 | |
| EC12E2420301 | Standard 3 to 20mN･m | 24 | recommended |
| EC12E2440301 | Lightest (jog) 3±2mN･m | 24 | recommended |
Extra
| name | pcs | type | package | description |
|---|---|---|---|---|
| MIDI cable (DIN5 M to jack 3.5) | 1 | Cable | Cable | TRS to DIN5 MIDI cable (Type A) for use external MIDI hardware |
| YS-SK6812MINI-E | 22 | RGB LED | 3228SMD | RGB LEDs |
OLED
You can choose any one of the following display models:
| name | pcs | type | package | description |
|---|---|---|---|---|
| TZT 1.3" OLED 64×128 i2c SSD1312 | 1 | Display | Module | |
| TZT 1.3" OLED 64×128 i2c SH1107 | 1 | Display | Module | recommended |
Pins
| Module pin | MCU pin |
|---|---|
| GND | GND |
| VCC | 3.3V |
| SDA | GPIO20 |
| SCL | GPIO21 |
Headphone amp
Formally, you should not connect headphones directly to the DAC or PWM output without an amplifier; however, in practice, it works fine directly, making an amplifier highly optional. If you decide to use one, you can choose any of the following headphone amplifier models:
| IC | mW | size | price | description |
|---|---|---|---|---|
| TPA6132 | 25 | S | 90 | |
| TDA1308 | 40-80 | S | 71 | |
| MAX4410 | 80 | M | 157 | |
| MAX97220 +++ | 125 | 20x24 | 225 | tested |
| OPA1622 | 145 | L | 113 | |
| LM4881 | 150 | M | 60 | |
| TPA6112 & SGM4812 | 150 | M | 183 |
DAC
GY-PCM5102 I2S PCM5102A module
Pins
| Module pin | MCU pin / Connection |
|---|---|
| GND | GND |
| VCC | 5V |
| BCK | GPIO17 |
| LRCK | GPIO18 |
| DIN | GPIO19 |
| SCK | GND (solder jumper next to SCK pin or wire to GND) |
Build guide
- Solder all components starting from the lowest profile to the highest in the following order:
- Diodes
- Hotswap sockets
- RGB LEDs
- For NC7WZ16P6X (U2): the Pin 1 indicator on the IC consists of two dots on the bottom side (where the leftmost dot marks Pin 1), which aligns with the silkscreen tick mark on the PCB footprint.
- Resistors
- Capacitors
- Jacks (recommended colors: green for MIDI IN, yellow for MIDI OUT, black for Audio OUT)
- H11L1 (U1): the Pin 1 indicator on the IC is a dot on the bottom side, which aligns with the silkscreen tick mark on the PCB footprint.
- Encoders
- Solder two jumpers on the board to the
LINEposition (if you plan to use PWM audio). - Solder the
5V/3V3jumper to the required position. This jumper controls the supply voltage of the NC7WZ16P6X (U2) IC. This affects the voltage of the MIDI OUT jack (for 5V, you must change resistors R3-R4 to 220 Ohm) and the PWM audio output level (5V increases the volume significantly, but might introduce noise from the USB power line).
- Connect external modules if needed:
- DAC
- Solder the jumpers on the back of the module: 1L, 2L, 3H, 4L
- Solder the jumper bridge next to the SCK pin on the module (bridges SCK to GND to enable internal PLL for 3-wire I2S)
- Desolder or cut off the audio jack from the module, as it takes too much space and won't fit in the case.
- Connect using wires:
- GND on the module to GND on the PCB
- LOUT on the module to JACK L OUT on the PCB
- ROUT on the module to JACK R OUT on the PCB
- VIN to 5V
- LRCK to GPIO18
- DIN to GPIO19
- BCK to GPIO17
- Solder two jumpers on the board to the
AMPposition
- OLED
- GND to GND
- VCC to 3.3V
- SDA to GPIO20
- SCL to GPIO21
- Headphone amp
- GND
- VCC to 3.3V
- L- to GND
- R- to GND
- L+ to the audio source PWM/DAC LEFT CHANNEL
- R+ to the audio source PWM/DAC RIGHT CHANNEL
- LOUT to the audio jack OUT LEFT CHANNEL
- ROUT to the audio jack OUT RIGHT CHANNEL
- Solder two jumpers on the board to the
AMPposition
- DAC
- Assemble the device into the case
- Flash the required firmware
Parts
88| Qty | Value | Footprint | References |
|---|---|---|---|
| 22 | YS-SK6812MINI-E | mkl:LED_YS-SK6812MINI-E_1side | LED1, LED2, LED3, LED10, LED11, LED12, LED13, LED14, LED15, LED16, LED17, LED18, LED19, LED20, LED21, LED22 +6 |
| 17 | 1N4148W | mkl:D_SOD-323_1side | D1, D2, D3, D4, D5, D6, D7, D8, D10, D11, D12, D13, D14, D15, D16, D17 +1 |
| 16 | SW_PUSH | mkl:SW_choc12_hotswap | SW1, SW2, SW3, SW4, SW5, SW6, SW7, SW8, SW9, SW10, SW11, SW12, SW13, SW14, SW15, SW16 |
| 4 | 100nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C3, C4, C5 |
| 4 | MountingHole | didSwitch:mountingHole | H1, H2, H3, H4 |
| 4 | RotaryEncoder_Switch_MP | mkl:RotEnc_Alps_EC12E-SWitch_Vertical_H20mm-without_SW | RotEnc1, RotEnc2, RotEnc3, RotEnc4 |
| 3 | Jumper_3_Open | Jumper:SolderJumper-3_P1.3mm_Open_RoundedPad1.0x1.5mm | JP1, JP2, JP3 |
| 3 | PJ-313 | mkl:JACK_PJ-313A_1side | J2, J3, J4 |
| 2 | 220R | mkl:R_0603_1608Metric_1side | R1, R5 |
| 2 | Conn_01x03_Socket | Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical | J1, J5 |
| 2 | LOGO | LOGO | G1, G43 |
| 1 | 1.8k | mkl:R_0603_1608Metric_1side | R7 |
| 1 | 100R | mkl:R_0603_1608Metric_1side | R6 |
| 1 | 10R | mkl:R_0603_1608Metric_1side | R4 |
| 1 | 33R | mkl:R_0603_1608Metric_1side | R3 |
| 1 | 470R | mkl:R_0603_1608Metric_1side | R2 |
| 1 | 47uF | Capacitor_SMD:C_1210_3225Metric_Pad1.33x2.70mm_HandSolder | C2 |
| 1 | H11L1 | Package_DIP:DIP-6_W8.89mm_SMDSocket_LongPads | U1 |
| 1 | NC7WZ16P6X | mkl:SOT65P210X110-6N | U2 |
| 1 | rp2040-zero | mkl:MCU_rp2040-zero | MCU1 |
Questions
How big is the Omsk PCB?
It measures 76.1 × 116.7 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Omsk use?
88 parts, built around the NC7WZ16P6X, H11L1, 1N4148W and PJ-313. 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 Omsk KiCad files?
From the aroum/omsk repository on GitHub, at the commit this page was made from: the board is hardware/pcb/omsk.kicad_pcb and its schematic hardware/pcb/ENC.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Omsk design in my own project?
Its repository publishes it under the GPL-3.0 licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).
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