Detect together: groups, rallies and how to use both

Most detecting on DetectID is solo — one pair of headphones, one machine, one set of pins on a private map. But a fair slice of the hobby is social: the regular pair of mates who detect a permission every other Sunday, the club that holds a Saturday meet once a month, the once-a-year charity rally with a hundred people on a stubble field. The new Detect togetherpage gives all of that a home in DetectID, with two patterns — Groups for the regulars, Rallies for the events — sharing the same underlying live-session machinery.

What “Detect together” actually is

Open app.detectid.co.uk/togetherand you’ll see a single hub with two panels: your Groups on the left, your Rallies on the right. The page exists because the two features answer different questions, but they share enough plumbing — a live shared session view, a combined heat map, a per-event leaderboard — that it’s less confusing to keep them in one place than to scatter them across the menu.

Whichever you join, the same things light up in the rest of the app:

• Every find you upload while the session is live attaches to the group or rally automatically. No re-tagging, no fiddly form fields.
• The shared heat map aggregates everyone’s pins, blurred to a sensible precision so nobody’s permission is inadvertently published.
• The roster shows you who else is in — useful for keeping a quick mental note of where everyone is on the field.

Groups vs Rallies — which one do you want?

The short answer: Groups are a small persistent crew of friends, Rallies are an event with a defined start and end. They overlap in mood — both feel sociable — but they behave differently and you join them differently.

Two pals who detect the same farm every Sunday want a Group. A club organising a charity dig with thirty people on the sign-in sheet wants a Rally. A family of four where two adults and two teens detect together at weekends wants a Group. A federation hosting their annual summer event wants a Rally. If you’re unsure: ask whether the thing has an end date. If yes, Rally. If no, Group.

How the code-based joining works

Both features use a code that the creator shares and the joiner types in. The codes look different so you don’t mix them up:

• Groupsgenerate a three-word hyphenated phrase from a curated detectorist-friendly vocabulary —amber-coin-meadow, stubble-bronze-lane,silver-thistle-furrow. The phrase is easy to read aloud over a patchy phone signal, easy to text without typos, and friendly enough to share without it feeling like a serial-number handoff.
• Ralliesgenerate a short alphanumeric stem from the rally name plus a 2-digit suffix — the long example is MERCIA26, the short fallback is a random alpha-numeric string. Short codes work better on a printed gate-poster and at a sign-in table where you might be calling them out across a marquee.

Both can be shared as a QR code as well. For Groups the QR lives on the group page itself, for Rallies on the printable A4 organiser poster. Scan with any phone camera, tap the notification, and you’re in — magic-link sign-in handles the rest if you’re not already signed into DetectID.

Codes are case-insensitive on entry and stay valid for the life of the group or rally. You can’t guess a group code by cycling combinations — the vocabulary plus position permutations give well over a million possibilities, gated behind rate limiting at the join endpoint.

The live session and the heat map

DetectID already has a per-user live session concept: open/finds/map, hit Start session, and your finds for the next few hours are tagged to that walk. When you’re inside a Group or a Rally that’s currently live, that session does two things at once: it tags your finds to your personal session for your own records, and it shares them with the group or rally feed.

The shared heat map is the visible payoff. As people upload, coloured dots accumulate on the map for the whole group or rally to see. Density warms up where multiple people have found things. Crucially, the shared map honours the strictest privacy precision among the participants — if any one attendee has set their finds to 1km precision, that 1km-blurred dot is what the whole group sees, not anything sharper. We don’t leak permission locations through the group surface.

What shows up on the page for each plan

The Detect together page itself loads for every signed-in user, but what each tier can do differs:

• Free.You can join Rallies (any code). Groups are read-only at Free — if a friend creates a group and invites you, you can be added, but you can’t create groups yourself. Ads as normal everywhere else.
• Basic.You can create and join Groups (2–10 people). You can join Rallies. The page is ad-free as part of Basic’s normal entitlements.
• Premium.Same as Basic plus a richer post-session report (PDF), the Roman roads and historic OS overlays on the shared heat map, and the 5km PAS nearby finds layer overlaid on the group’s area.
• Rally Captain.If you organise a rally that hits 10+ attendees and 20+ finds, you get three months of Premium-equivalent access automatically — the perk stacks per qualifying rally. See the Rally Captain perk for the full mechanics.

Worked example — the same Saturday, two surfaces

Imagine the Mid-Anglia Detectorists. They have a regular Sunday permission worked by four mates — that’s a Group called amber-coin-meadow. Once a quarter the club runs a Saturday dig open to thirty members — that’s a Rally with the code MIDANG26. Three of the four Sunday regulars also attend the quarterly Rally. Their finds from the Rally Saturday go into the Rally feed and the heat map. Their finds from the regular Sunday go into the Group feed. The two feeds don’t cross-contaminate, because Group sessions don’t fire during a Rally window and vice versa — the live-session machinery picks the most specific active context and tags to that one.

Where to next

• Detecting groups: 2–10 friends, one three-word code — the full Group walkthrough.
• Rallies on DetectID: organising an event, joining as an attendee — the full Rally walkthrough.
• The Rally Captain perk — earning Premium for free — if you organise rallies regularly, this is how the numbers add up.