2 layers175 × 45.8 mm
Nixieclocklogic V2-2
broedschroed/NixieClockUltra
ESP32-S3 powered Nixie tube clock with direct-drive IN-12A tubes, web UI, IR remote, and RGB ambient lighting
37 partsMIT
2 layers175 × 45.8 mm
Nixieclockin12 V2-1
broedschroed/NixieClockUltraESP32-S3 powered Nixie tube clock with direct-drive IN-12A tubes, web UI, IR remote, and RGB ambient lighting
- Size
- 175 × 45.8 mm
- Copper layers
- 2
- Thickness
- 1.6 mm
- Parts
- 169
- Nets
- 252
- Pads
- 608
- Tracks, vias
- 1,907, 137
- Routed
- Yes
- KiCad
- KiCad 10.0 (file 20260206)
- Created
- 12 Jul 2026
- Updated
- 13 Oct 2026
Overview
Nixieclockin12 V2-1 is an open-source printed circuit board by broedschroed, from the broedschroed/NixieClockUltra repository on GitHub, published under the MIT licence. It is a 2-layer board of 175 × 45.8 mm with 169 parts on 252 nets, routed with 1,907 tracks and 137 vias.
It is built around the MCP23017-E/SO and WS2812B. Its parts include 76 resistors, 60 transistors, 10 ICs, 10 diodes and 4 capacitors. It belongs with the lEDs and displays and home automation and IoT boards and the ESP32 boards of this library.
Main components
2README
README.mdNixie Clock Ultra
A handcrafted Nixie tube clock built around an ESP32-S3, combining the warm, unmistakable glow of six IN-12A Nixie tubes with modern connectivity: a full web interface, IR remote, RGB ambient lighting, and automatic NTP time sync.
🌐 Project website: https://broedschroed.github.io/NixieClockUltra/
Highlights
- Direct drive, zero ghosting — every cathode is switched by its own transistor (via MCP23017 I/O expanders), so there's no multiplexing and no flicker or ghosting between digits.
- Web interface — full control from any browser on the local network, no app required.
- IR remote — seven learnable functions (set time, brightness, animation, slot effect, colon toggle, ...).
- RGB ambient lighting — 10x WS2812B NeoPixels with rainbow, static, and pulse animation modes, plus a slot-machine digit-shuffle effect.
- Night mode — dims the tubes via hardware PWM on the anode voltage, triggered by a schedule or an onboard light sensor (LDR).
- Soft digit transitions — smooth crossfade between digits instead of an abrupt switch.
- DS1302 RTC with automatic NTP sync when connected to WiFi.
Hardware
- ESP32-S3 (native USB)
- 6x IN-12A Nixie tubes, driven directly through 4x MCP23017 I2C expanders
- ~170V HV supply for the tubes, switched via a TLP627 opto-coupler for hardware-PWM dimming
- DS1302 RTC
- 10x WS2812B NeoPixels
- VS1838 IR receiver
- 4 physical buttons (Set / Up / Down / Light)
KiCad sources for the logic board and the Nixie display board are included
under docs/system/.
Repository layout
*.ino/*.h— firmware (Arduino/ESP32 sketch)test/— host-side unit tests for the fade mathdocs/manual/— user manualdocs/system/— system documentation and KiCad hardware sourcesdocs/website/— source of the project website (deployed via GitHub Pages)
Building
Open the sketch in the Arduino IDE (or arduino-cli) with the ESP32 core
installed, board set to an ESP32-S3 module with USB CDC on Boot: Enabled,
and the required libraries (ArduinoJson, ESPAsyncWebServer, IRremoteESP8266,
Adafruit NeoPixel). Flash and connect to the NixieClockCS WiFi hotspot (or
your home network once configured) to reach the web interface.
License
Released under the MIT License.
Parts
169| Qty | Value | Footprint | References |
|---|---|---|---|
| 64 | 3k3 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R1, R2, R10, R11, R12, R13, R14, R15, R16, R17, R18, R19, R20, R21, R22, R23 +48 |
| 60 | SMBTA42 | MyLibrary:MyTSOT-23 | Q1, Q2, Q10, Q11, Q12, Q13, Q14, Q15, Q16, Q17, Q18, Q19, Q20, Q21, Q22, Q23 +44 |
| 6 | 22k | Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal | R65, R66, R67, R68, R69, R70 |
| 6 | MyTLP627 | Package_DIP:DIP-4_W7.62mm | U5, U6, U7, U8, U9, U10 |
| 6 | ~ | MyLibrary:My-IN-12B | NX1, NX2, NX3, NX4, NX5, NX6 |
| 5 | 100Ω | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R71, R72, R73, R74, R75 |
| 5 | WS2812B | LED_SMD:LED_WS2812B_PLCC4_5.0x5.0mm_P3.2mm | D2, D3, D4, D5, D6 |
| 4 | 100nF | Capacitor_SMD:C_0805_2012Metric_Pad1.18x1.45mm_HandSolder | C1, C2, C3, C4 |
| 4 | MCP23017-E/SO | Package_SO:SOIC-28W_7.5x17.9mm_P1.27mm | U1, U2, U3, U4 |
| 4 | WS2812B | MyLibrary:YF923 | D7, D8, D9, D10 |
| 1 | 1k5 | Resistor_SMD:R_0805_2012Metric_Pad1.20x1.40mm_HandSolder | R76 |
| 1 | 6x WS2812B-SMD | LED_SMD:LED_WS2812B_PLCC4_5.0x5.0mm_P3.2mm | D1 |
| 1 | AnodeSW | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J3 |
| 1 | HV | Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical | J2 |
| 1 | Logic | Connector_PinHeader_2.54mm:PinHeader_1x08_P2.54mm_Vertical | J1 |
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Questions
How big is the Nixieclockin12 V2-1 PCB?
It measures 175 × 45.8 mm and has 2 copper layers, 1.6 mm thick.
What parts does the Nixieclockin12 V2-1 use?
169 parts, built around the MCP23017-E/SO and WS2812B. 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 Nixieclockin12 V2-1 KiCad files?
From the broedschroed/NixieClockUltra repository on GitHub, at the commit this page was made from: the board is docs/Leiterplatten/IN12-Board/nixieclockin12_V2-1.kicad_pcb and its schematic docs/Leiterplatten/IN12-Board/nixieclockin12_V2-1.kicad_sch. PCBKit opens the board in the browser, with nothing to install.
Can I use the Nixieclockin12 V2-1 design in my own project?
Its repository publishes it under the MIT licence: you may reuse it on that licence's terms (keep the author's notice, and for a copyleft licence share your changes alike).