Fixing the Portobello Police Station Clock

Original Article ↗ Hacker News Discussion ↗

An article about reviving the 19th‑century clock at Portobello Police Station in Edinburgh prompts a broader look at how old public clocks and bell mechanisms are maintained in the modern era. Commenters unpack the likely design of the improvised chime controller — from PIC microcontrollers and sealed lead‑acid backup batteries to a status LED possibly blinking Morse‑coded hours — and contrast this with traditional weight‑driven and synchronous‑motor clockworks. Many respond with enthusiasm for the blend of community volunteering, hands‑on engineering, and preservation of local heritage, sharing related projects, safety tips, and resources for getting involved in similar efforts.

Overall Reaction

  • Many readers found the story delightful, “what the internet should be,” and a refreshing break from AI-heavy content.
  • Locals recognized the building and other Edinburgh landmarks; some shared personal connections (family who worked there, nearby work, neighborhood memories).
  • Several commenters expressed envy of such a project and a desire for similar hands‑on community efforts.

Clock Mechanics & Electronics

  • Observers note the original weight-driven parts and striking train seem largely bypassed.
  • Time is now driven by a small motor (likely synced to mains frequency) plus a pendulum; the large geared motor and chain appear dedicated to driving the chime mechanism.
  • The chime is apparently triggered on the hour but has no direct knowledge of the indicated time, so clock time and chime schedule must be set separately.
  • Some argue “just” setting the time is still a valid repair, especially with unknown and fragile legacy systems.

Status LED, Battery, and Date Codes

  • A key mystery is the “Status” LED pattern: long–long–short–short–short.
    • One camp strongly favors Morse code (7), possibly used for setting or indicating the hour.
    • Another suggests a binary interpretation (11000 → 24), but others counter that Morse is more intuitive for non‑engineers.
  • The board appears to be a small‑scale, older microcontroller design: single‑sided PCB, no silkscreen, hand‑assembled wiring.
  • Debate over the backup battery date code (e.g., “090323”):
    • Some claim DDMMYY or YYMMDD; others cite manufacturer docs indicating DDMMYY.
    • Lifespan estimates suggest it should be replaced proactively, though as a backup it may not affect normal operation much.

Safety, Maintenance, and Monitoring

  • Concerns raised about structural safety: possible makeshift flooring vs substantial beams; advice to be cautious about holes and joists.
  • Suggestions for future maintenance include adding non‑slip treads to ladders and installing an IP camera to remotely monitor gears, motors, and the LED.
  • Some wish the team had improved documentation and debugability for future caretakers.

Other Clocks and Bell Towers

  • Multiple recommendations of related content: bell‑tower repair videos, Big Ben tours, industrial steeplejacking and steam‑era documentaries, and historic tower clocks (e.g., Bromo Seltzer Tower).
  • Discussion of other Edinburgh clocks and heritage objects needing care, and mixed experiences with the council restoring or quietly “storing” them.

Airport Swab & Security Tangent

  • A long subthread spins off from an anecdote about dusty clothes triggering airport explosives tests.
  • Commenters describe ion mobility spectrometry: very sensitive to certain chemical fragments (e.g., glycerin, nitrates), designed with plenty of false positives.
  • Stories highlight both false positives (e.g., baby wipes, dusty attics) and apparent false negatives (gunpowder residue not detected), reinforcing views that much of the process feels like “security theater.”

Community & Volunteering Reflections

  • Readers ask how to get involved in similar community projects.
  • Suggestions include local maker spaces, service/volunteer clubs, school organizations, and simply approaching community venues that might have neglected infrastructure.

Miscellaneous Observations & Humor

  • Jokes about time puns, Orwellian “thirteen o’clock,” Resident Evil police‑station vibes, Portobello mushrooms vs Portobello the place, and British vs international date formats.
  • Some express nostalgia for an older web culture of personal blogs and niche technical writeups, seeing this story as a rare modern example.