smoke-alarm-auditor

Use when a smoke or CO alarm chirps, or for a home safety audit — decodes beep patterns (low battery vs CO vs fault vs end-of-life) by brand behavior, dates the whole house (10-year smoke / 7-year CO / battery schedules), sizes the install plan to NFPA 72 (every bedroom, outside sleeping areas, per floor, interconnected), and prints a placement anti-pattern list (dead air zones, kitchen false alarms).

Overview

The smoke alarm chirps at 3AM. Nobody remembers what the pattern means, whether it's the battery or the unit dying, or how old the units even are. Meanwhile the actual safety facts stay unknown in most homes: smoke alarms have a 10-year life, CO alarms 7, every bedroom needs its own alarm plus one outside each sleeping area and one per floor (interconnected), and a chirp pattern is a language — one beep/minute is low battery, but 3-4 quick beeps repeating is SMOKE, 4-5 with a pause on CO units is CARBON MONOXIDE.

This skill:

1. Decodes chirp patterns — low battery / smoke / CO / fault / end-of- life, with the caveat list (patterns vary by brand; the tool lists First Alert / Kidde conventions).
2. House audit — inventory with install dates, computes age vs the 10-year (smoke) and 7-year (CO) end-of-life math, flags the oldest first, generates a replacement plan.
3. Battery schedule — 9V/AA replace yearly vs 10-year sealed units; lithium vs alkaline chirp behavior.
4. Coverage plan to NFPA 72 — room-by-room requirements from a bedroom/floor count, interconnected-vs-standalone, hearing-impaired (strobe/shaker) options.
5. Placement anti-patterns — the dead-air corners, kitchen 10-ft rule, garage never, CO height truth (floor vs ceiling barely matters — placement relative to sources does).

When to Use

• An alarm is chirping and you need to know what it's saying now
• Moving into / auditing a home: are units expired? Is coverage legal- -ish and adequate?
• After replacing batteries and the chirp continues (end-of-life unit)
• Deciding units for a renovation or a new baby's room
• A CO alarm went off and you need the immediate-action script

Don't use for: commercial fire systems (NFPA 72 commercial code + licensed inspectors), heat-detector-only specs for attics (simple rule in references), or investigating a current fire — leave and call emergency services.

Quick Start

bash

python3 scripts/alarms.py chirp --pattern "1 beep every minute"
python3 scripts/alarms.py chirp --pattern "3 quick beeps repeating"
python3 scripts/alarms.py audit --units unit.json
python3 scripts/alarms.py coverage --bedrooms 3 --floors 2
python3 scripts/alarms.py placement --room kitchen
python3 scripts/alarms.py co --event "alarm sounded 30 min ago"

unit.json format: [{"id":"hall-1","kind":"smoke|co|combo", "installed":"2019-04","battery":"9v|aa|sealed10"}]

Stdlib-only, no network.

The Beep Language (what patterns mean)

Pattern	Meaning	Action
~1 chirp / 30-60 s, steady for hours/days	LOW BATTERY	replace battery (or unit if sealed)
3-4 loud fast beeps, pause, repeat	SMOKE ALARM	treat as fire: evacuate, verify
4 fast beeps + voice/"CO" or 5 beeps on Kidde	CARBON MONOXIDE	evacuate, ventilate, call for CO eval
3 chirps (unit not 1/minute) or 5 every minute on some models	UNIT FAULT / EOL	replace the unit
Chirp continues after NEW battery	END-OF-LIFE (sensor)	replace unit — it's 10 years old
Brief chirp at exact same time nightly	temperature dip + weak battery	replace battery; it's marginal

Brand variance is real: First Alert CO = 4 beeps + "Warning carbon monoxide"; Kidde CO often 4 beeps repeating, EOL = 5 chirps/minute. The decoder prints both conventions and tells you to confirm against the label on the back of the unit (which also carries the manufacture date).

The Age Rules

Unit type	Service life	Why it expires
Ionization/smoke (any brand power)	10 years from manufacture	sensing chamber drifts; dust + age
Photoelectric smoke	10 years	same
CO alarm (standalone or combo)	7-10 years (electrochemical cell dies)	label date governs
Sealed 10-year lithium units	battery lasts the unit's life; still expires at 10y	chirps = replace whole unit
9V/AA replaceable	battery yearly (or at chirp)	alkaline fades with cold

Manufacture date is printed on the BACK of the unit (MMYYYY or similar). If your home's alarms have no dates you can find, they're older than 10 years — replace them all.

Workflow

1. Chirp now? chirp --pattern "..." → what it means + immediate action. If smoke/CO pattern: stop, follow the evacuation script.
2. Inventory: walk the house, photograph the back of each unit (date label), note kind and battery type → unit.json.
3. audit --units unit.json → ages, EOL flags, ordered replacement plan (oldest + bedrooms first).
4. coverage --bedrooms N --floors F → NFPA-72-based unit count and placement plan; check gaps.
5. placement --room <room> for each planned spot → anti-pattern check (dead-air corners, kitchen proximity, garage).
6. Buy list: sealed 10-year combo units unless you prefer replaceable batteries; interconnect (wireless or hardwired) for any multi-floor.

Common Pitfalls

1. Battery-swap as a reflex. A chirping unit that keeps chirping after a new battery is telling you it's 10 years dead. Read the back date.
2. One alarm per home. The minimum-legal-legacy setup. Bedrooms, outside sleeping areas, every floor including basement; heat detector in the garage/attic (never smoke there — dust/exhaust false alarms).
3. Kitchen placement errors. Within 10 ft of cooking appliances = constant false alarms → people disable units → the fatal classic. Photoelectric near (not in) kitchens false-alarm less.
4. Dead-air mounting. Within 4 in of a corner or peak ceiling apex = smoke may not reach the sensor early. Wall mounts: top of alarm 4-12 in below ceiling.
5. CO units at the wrong ceiling height debate. CO mixes nearly evenly — height matters far less than proximity to sources (fuel appliances, attached garage) and sleeping areas (to wake you).
6. Removing the battery to silence nuisance alarms. The single most common fatal error. Move the unit, replace with photoelectric, never leave it dead.
7. Forgetting interconnected units exist. Hardwired/wireless-linked units all sound together — one kitchen trigger wakes the whole house; also means "which unit is chirping?" requires per-unit silence button hunting (listen close: chirps localize poorly).
8. Renter assumptions. Landlord duties vary by jurisdiction, but the 10-year rule doesn't. Ask for the install date; test on move-in.

Verification Checklist

• Chirp pattern decoded against back-of-unit label (brand variance)
• Every unit's manufacture/install date recorded
• No unit older than 10y (smoke) / per-label (CO); oldest flagged
• Coverage: every bedroom + outside sleeping areas + per floor
• Placement: no dead-air corners, 10 ft from cooking, none in garage
• Test button monthly; date of last test recorded
• Replacement plan dated and (if renting) sent to landlord in writing

Safety Disclaimer

This skill encodes widely published NFPA consumer guidance; codes vary by jurisdiction and change. It cannot hear your alarm — when the decoder says smoke or CO, act first (evacuate/ventilate/call) and verify after. CO symptoms (headache, nausea, confusion) with an active alarm = fresh air immediately and emergency evaluation.