mangavalkandClaude Opus 5.5
3818e920fc
Notes on the RetroModding IN-12 v2 clock (pinout, programming header, plan for ESP_UniClock) and the maker's v2 schematic. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
3.2 KiB
Nixie clock: notes for Claude
An AliExpress WiFi nixie clock (4x IN-12 + 2x IN-3 neon dots, 8x WS2812) that is being moved from its closed stock firmware to ESP_UniClock (https://github.com/gpeter62/ESP_UniClock) with ArduinoOTA and Home Assistant (MQTT) support.
The device
- On the network at 10.1.1.97 (WiFi
dlink-iot). Stock web UI on port 80, nothing else open: no OTA, no API, no MQTT. - Board: RetroModding (Konstantin Repnikov) "NixieIN12v2 HV2.0", stock firmware SV1.3 (©2020). ESP-12 (ESP8266, MAC 30:83:98:99:BF:DE, Espressif).
- Powered by USB-C 5 V only (no DC jack). Most likely the maker's "v2.0L lightweight 5 volt version". The user says the PCB looks different from the 12 V v2 board.
- No buttons fitted, only the light sensor.
- Stock settings (2026-10-25): time zone +01:00, EU DST on, NTP
time.euro.apple.com, brightness auto, 24 h. Stock DST might not work: check in late March.
Pinout (from the 12 V v2 schematic, docs/schematic_v2_12V.jpg)
Not yet verified on this 5 V board. The stock firmware image is the same for both, which suggests the GPIOs match.
| Function | GPIO |
|---|---|
| 74HC595 DATA / CLOCK / LATCH (OE tied to GND) | 13 / 14 / 15 (15 has 1k pull-down) |
| DS3231M RTC SDA / SCL | 4 / 5 |
| WS2812 data | 12 |
| Photoresistor (LDR, 10k to GND) | ADC (A0) |
| BTN1 / BTN2 (not fitted) | 0 / 2 |
Two chained 74HC595s make one 16-bit word, all bits active-high:
- U1 QA..QH = cathodes 0..7, U2 QA = cathode 8, QB = cathode 9 (via 2x ULN2003, shared by all tubes)
- U2 QC = P1 (neon dot 1), QD..QG = anodes A1..A4 (MMBTA42/92), QH = P2 (neon dot 2, and the decimal point if jumper JP2 is closed)
- The display is multiplexed: one anode on at a time. Which physical tube is A1 is unknown.
Programming header
Header on the PCB: GND, GPIO0, RST, RXD, TXD, 3.3V. The USB-C port only supplies power. Flashing is done with a CH340C board on COM7 (COM3 is another device; leave it alone). Wiring: GND-GND, adapter TXD -> clock RXD, adapter RXD -> clock TXD, adapter 3.3V not connected (the clock is powered from its own USB-C). No auto-reset: to enter flash mode, hold GPIO0 to GND, tap RST to GND, then release GPIO0.
- esptool is installed for the user (
python -m esptool, v5.6.0). firmware/stock/holds the stock flash dump. Never overwrite or delete it; it is the only way back to SV1.3 (write-flash 0 <dump>). Dumps are gitignored because the flash holds the WiFi password; never commit them.
Constraints
- The 170 V tube supply is live whenever USB-C is connected.
- Hardware is only reachable via the user: anything that needs RST/GPIO0 or looking at the tubes must be asked of them. Builds can be checked here, but runtime behaviour can't.
- Show the exact plan before making changes to the device (flashing, saving settings).
Plan
- Dump and inspect the stock firmware (version strings, pins if possible).
- Write a test sketch that steps through the 16 shift-register bits, to verify the pinout and the tube order.
- Add a 74HC595-multiplex driver + CLOCK config to ESP_UniClock, plus ArduinoOTA and Home Assistant controls (display on/off, brightness, LEDs); its stock MQTT only publishes sensors.
- Work continues in VS Code (PlatformIO).