Silence is an alarm
Every device carries a heartbeat. If a sensor, the house, or Guardian's own cloud goes quiet, an independent watchdog raises the alert. A dead box nobody notices is the failure we designed against first.
Kresvik ApS · Denmark · est. 2026
The house is empty. Someone is still paying attention.
Kresvik is a Danish product studio — concept to MVP, without the drama. Our newest product is Guardian: monitoring for summerhouses, cabins and every home that stands empty for months, built on one rule — silence is an alarm.
01 — Guardian · new
A vacant home that answers back.
Water finds the floor in January. Frost finds the pipes. Power fails quietly. Guardian sits in the house year-round and reports over its own cellular link — temperature, humidity, leaks, doors, motion, light and mains power. When anything goes wrong, you hear about it in seconds. When the house goes silent, you hear about that too.
Power failure reported in seconds
Mains loss is published before the system falls back to its battery — target under ten seconds — then Guardian keeps reporting through the outage for more than a day.
No camera. No microphone. Ever.
Privacy is a hard product boundary, not a setting. Guardian knows a door opened and a room got cold — never what anything looks or sounds like.
02 — The hardware
Three quiet machines.
One main unit carries the property's single cellular connection. Battery siblings and leak pucks report to it over long-range sub-GHz radio — through walls, floors and out to the far shed.
Main unit
The property's brain. Cellular uplink, LoRa base, its own climate sensors, two wired leak probes — and a battery that keeps it reporting when the power is out.
- Uplink
- LTE-M / NB-IoT
- Outage backup
- > 24 h
- Power-cut alert
- < 10 s
One per property
Sibling unit
One per room that matters. Temperature, humidity, light, door contact and motion — awake for milliseconds, asleep for everything else.
- Battery
- 3 yr · 2×AA lithium
- Reports
- Every 30 min
- Door / motion
- Instant
Per room · works to −40 °C
Leak puck
A disc under the water heater, washing machine or sink. Sensing contacts on both faces, so it works whichever way it lands. Silent puck? That's an alert.
- Battery
- ½AA lithium · years
- Heartbeat
- Daily
- Water alert
- Immediate
Per wet spot · Ø45 × 23 mm
Radio LoRa 868 / 915 MHz
Encryption AES-CCM per device
Uplink one SIM per property
Alerts app · SMS · e-mail
Cloud dependency none for sensing
03 — How it works
Pressure, then a clean vertical release.
Readings gather at the main unit and surface the moment they matter. Alerts reach you with the app, and without it — SMS and e-mail are first-class paths, not fallbacks.
In the rooms
Siblings & pucks
Battery sensors sleep for years, wake to measure, transmit, and sleep again.
In the hallway
Main unit
Collects every reading, watches the mains, holds the property's one SIM.
Off-site
Kresvik cloud
Stores, decides, and is itself watched by an independent dead-man's watchdog.
Wherever you are
You
App, SMS or e-mail — a calm feed most days, an unmissable message the day it counts.
04 — Pilot · winter 2026 / 27
Ten properties. One Nordic winter. Every alert accounted for.
Guardian is in development, heading into a pilot across Danish summerhouses and US cabins this winter. If you manage, sell or insure homes that stand empty — we'd like one of them to be yours.
05 — The studio
Built end to end in one house.
Kresvik takes ideas from concept to MVP and runs what it ships. Guardian is engineered here across the whole stack — firmware, radio protocol, Linux hub, cloud services and the enclosures themselves — so when something matters, there's no vendor between us and the fix.
Firmware TinyGo
Services Go
Radio custom LoRa P2P
Enclosures parametric CAD
Alerting watchdog-first