Migrating from a paper logbook

You have been logging fridge temperatures by hand for years. The auditor accepts your paper. Why bother changing? Three reasons:

1. The hourly time wasted reading and writing.
2. The audit-trail gap when a manager forgets a round.
3. The legibility problem when an inspector wants the log for the month of February two years ago.

This page describes the six-month plan that minimises both the time cost and the inspector's anxiety. It assumes you are a small café or restaurant; chains can compress the timeline.

Month 0 — install OpenSense

Follow the quickstart. Get one sensor per cold-storage unit. Verify a reading lands. Do not switch off the paper log yet.

Months 1–2 — parallel run

You keep doing the paper log as usual. OpenSense collects silently in the background. The paper log remains the official record; OpenSense is unproven.

What to watch in OpenSense during this period:

• False alarms (see first 30 days). Tune them out.
• Operator workflow. Does the morning round-taker know how to acknowledge an alarm if one fires? Train them.
• Probe placement. The first weeks reveal which sensors are in poor positions.

Month 3 — handover preparation

If everything has stabilised, prepare the handover:

• Print month 3's PDF.
• Sign the cover page of the PDF.
• Sign the last page of the paper log with the following text:

  "From this date, this paper log is closed. The temperature record continues digitally on OpenSense, account <your account email>, retrievable as PDF reports on demand and at month-end. Operator: <name>. Date: <date>."

• Store the paper log in your compliance folder, dated. Do not throw it away.

Months 4–6 — digital only

You no longer touch paper. OpenSense renders monthly. The PDF is delivered automatically (set up the monthly subscription).

What to do at the inspector visit:

• If the inspector asks for "the log", hand them the latest PDF on paper. Have it pre-printed; do not fumble for a printer.
• If they ask about a historical period > 1 month, open the dashboard on a tablet and walk them through. Most inspectors are satisfied.
• If they specifically ask for paper for an older period, render that period's PDF on the spot (takes ~30 s) and print.

Month 7+ — steady state

The paper folder lives in the office, untouched, as proof of continuity for the transition window. After 12 months you can move it to long-term storage.

The OpenSense PDFs are stored in the dashboard indefinitely (they regenerate on demand from raw data, which is retained 13 months). For your own compliance folder, download the monthly PDF locally the day it is rendered; keep 24 months on hand even though it is available on demand. Belt and braces.

The migration cover sheet

A printable template the auditor can sign. Customise the bracketed fields:

                  TEMPERATURE LOG — MIGRATION DECLARATION

  Site:           [Café Bratislava — main]
  Address:        [Hlavná 17, 81101 Bratislava]
  Operator:       [Jana Nováková]
  Previous log:   Paper logbook (binders, year-by-year)
  Current log:    OpenSense — account [grande.chuvash@gmail.com]
  Effective date: [2026-08-01]

  Paper logbook closed on: [2026-07-31]
  Last paper entry signed by: [______________________________]

  Inspector witness (optional):
  ___________________________   Date: ___________
  (signature)

  Operator declaration:
  ___________________________   Date: ___________
  (signature)

Keep this document next to the closed paper logbook.

What if the auditor refuses?

It happens, especially in jurisdictions with conservative inspector training. The fallback:

1. Resume paper logging immediately. OpenSense continues silently.
2. Print the OpenSense PDF and physically tape it inside the paper logbook for each month. The auditor sees both records; the paper continues to be the "primary" record but the digital evidence is collocated.
3. Document the auditor's reasoning. After 12 months, escalate politely: the practice elsewhere in the country, the explicit acceptance of digital records by national regulation (Slovakia: ŠVPS interpretation; Germany: BfR; Austria: AGES).

In our pilot of ~20 Slovak operators we have not yet hit an inspector who refused digital. We will document the first such case if it occurs.

What we never recommend

• Destroying the paper log before the migration is complete. The handover record needs both sides intact.
• Backfilling OpenSense with paper-log data. OpenSense's audit trail records that you back-filled, with what data, by whom. An inspector reading the audit log can tell you back-filled. Pretending the digital trail starts earlier than it does is worse than just admitting the install date.
• Cancelling OpenSense one month into the trial and re-starting paper. You lose the audit-trail continuity for the trial month; it looks suspicious in an inspection.

If you are going to try OpenSense, commit to the parallel-run period before evaluating. Premature cancellation is the most expensive way to migrate.