📊 Statistics & your data

What the trainer records about your darts, where that record lives, and the rules it follows.
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First things first: you can opt out — here's how, and why we hope you don't

Opting out is one line. Comment out DT_CENTRAL_URL in /etc/dart-trainer/config.env and restart:

sudo nano /etc/dart-trainer/config.env      # put a # in front of DT_CENTRAL_URL
sudo systemctl restart dart-trainer

Your rig then runs fully local: nothing leaves your Pi, and every game, score and statistic keeps working — the trainer is built local-first, so you lose no functionality on your own board.

Why we hope you stay in — three things only the central copy can do:

Backup. microSD cards die without warning. With central on, your complete throw history survives your card. Fully local means one card failure erases everything.
Playing together. The cross-rig leaderboards, stat comparisons and the 501 Elo board need one place every rig reports to — opt out and your scores exist only for you.
A model that knows your board. Your throws and corrections train the shared auto-scoring model. You'd still receive the models everyone else trains — but your board's own lighting, cameras and quirks would never be in the training data, so auto-scoring improves for everyone's board except yours.

New rigs start quarantined: their uploads are stored but excluded from model training and capped, until the rig is explicitly trusted by the admin. See the install page for the full “what your rig sends home” table.

Every dart, with its story

Since trainer 0.3.83, a throw isn't just a score — it is recorded together with the situation it was thrown into:

recorded	example
Where it landed	exact board position in millimetres, plus the score (T20, D16, MISS…)
What you were aiming at	in 501 the trainer knows from the game state: 32 left means this dart was thrown at D16; 170 left means T20. Every target game records its target per dart too.
What happened	bust, checkout, leg won, round halved (Bermuda), dart into a dead visit…
When	the true throw time — so session fatigue and pace can be measured later

Nothing is lost — by design. Undo marks a dart as voided instead of erasing it, a bust is recorded as a bust (it's a statistic, not noise), and an abandoned game keeps its throws. Corrections refine the record; they never destroy the original.

Local-first: your Pi owns your record

The source of truth for your statistics is a database on your own rig: /var/lib/dart-trainer/stats.db. It is written on every dart, works with no internet at all, and stays yours — if you opt out of the central service entirely (see below), you keep collecting and (as the stats screens land) viewing your full statistics locally.

What you get

Today: hit heatmap, grouping (mm), zone percentages, XP/level, daily streak, badges, per-mode leaderboards and the 501 head-to-head Elo board — all in 📊 my stats on the tablet. Any game can be played by 2–3 people passing one board — each player's throws count toward their own stats, and a friend can scan their player-ID QR to join.
Being built on the new data (collected now, screens coming): per-mode statistics for all 15 games — checkout % counted the standard way (doubles hit ÷ darts thrown while a double was on, comparable with the numbers other systems show), first-9 average, darts-per-target, miss maps around T20, aim-bias in millimetres (“you hit 8 mm low-left of T20”), fatigue over a session.

Player ID (optional)

You can claim a player ID on the tablet: 12 words, shown once, written on paper. They derive a cryptographic keypair (a Nostr-format npub — a pseudonymous public key). What it does today: enter your words on any rig and your complete statistics history is restored from the central backup, self-service — the recovery path for a dead SD card. What central stores: only the binding between your npub and your player name; the secret never leaves your rig. Strictly opt-in — everything works without one. The tablet can also show your words as a QR code (to save or share) and scan one back to sign in on a friend's board — the photo is decoded on the board itself and never stored. Lost your words and your rig? The operator can re-bind your name to a fresh ID on request (that's the deliberate, friends-scale fallback).

Data protection notice

Last updated: 15 July 2026 · applies to the dart-trainer app and the dataset/leaderboard service at dart-room.com

Who is responsible

This is a private, invite-only, non-commercial hobby and research project, operated by z3n (dart-room.com). Contact for anything data-related, including all requests listed below: z3nlabs@proton.me. The operator's full identity is disclosed on request via that address.

What is processed, and why

data	purpose	kept
Throw data — board coordinates, scores, per-throw game context (targets, busts, checkouts), throw timestamps	your statistics & leaderboards; training the open dart-detection model	until the project ends or you request deletion
Camera images of the dartboard captured per throw (3 cameras)	model training — this is the training data itself	until the project ends or you request deletion
Player name — free-text, chosen by you	attributing scores; shown on leaderboards	with the throw data
Rig identifier & calibration — a per-device id and the solved camera geometry	keeping every rig's data cleanly separate and re-scorable	with the throw data
Rig telemetry — app version, camera health, error log lines, feedback you send (with a screenshot of the app only if you tick the box)	diagnosing problems without anyone logging into your Pi	until no longer needed for diagnostics
Web-server logs — IP address, time, requested URL	operating and securing the service	14 days (rotated daily)

Legal basis, and how to say no

Participation in the shared dataset is the point of the project, and you were invited on that basis — uploading is therefore enabled by default on a fresh install (the rig enrolls itself). Your participation is voluntary and revocable at any time: it rests on your consent (Art. 6(1)(a) GDPR), given by installing and running the trainer with central enabled after reading this page and the install page.
Withdrawing is as easy as joining was — the one-line opt-out at the top of this page. It stops all future uploads immediately; it does not by itself delete what was already uploaded (ask, and it will be — see “Your rights”).
Web-server logs are kept on the basis of legitimate interest (Art. 6(1)(f) GDPR) in operating and defending the service.

Practical privacy notes

Use a nickname. The player name is free text and appears on leaderboards visible to the other participants (leaderboards are not public on the open internet; they require a participant token). Nothing forces you to use your real name.
Point the cameras at the board. The three cameras capture whatever is in their view at every throw. Mounted normally on the camera ring they see the board surface — mount them so they do not see the room or people.
No cookies, no trackers, no ads. These pages and the trainer set no cookies and load no third-party analytics. Authentication uses per-rig tokens, not accounts.

Where the data lives, and who sees it

Primary copy: your own rig, under your control.
Central copy: a server hosted with Oracle Cloud in Frankfurt, Germany (EU). Data is not transferred outside the EU and is not shared with, or sold to, any third party. Other participants see your player name and scores on the leaderboards — never your camera frames, feedback or telemetry.
Models trained on the collected data are published as model files (weights). They do not contain your throws or images in retrievable form; a model already trained and shipped before a deletion request cannot retroactively “un-learn”, but deleted data is excluded from all future training.

Your rights

Under the GDPR you can request, at any time: access to the data stored about you (Art. 15), rectification (Art. 16), erasure (Art. 17), restriction of processing (Art. 18), your data in a portable format (Art. 20), to object (Art. 21), and to withdraw consent with effect for the future (Art. 7(3)). Requests are handled free of charge and answered within one month at the latest (Art. 12) — in practice within days. (The GDPR's letter makes erasure conditional and lets manifestly excessive repeat requests be charged; neither matters here: because this project runs on your consent, withdrawing it obliges deletion — and beyond what the law requires, the operator's standing commitment is simpler: ask, and your rig's entire record is purged, no conditions.) One email to z3nlabs@proton.me (or a note via the in-app 💬 feedback button) is enough. You also have the right to complain to a data-protection supervisory authority.

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