How do you make a tag treasure hunt?
One tag at each station, holding the clue that leads to the next. Everything difficult is about the people rather than the tags: which phones can read, who taps for the group, and what happens when somebody finds station four before station two.
The shape of it
Each station holds a tag. The tag holds the clue to the next one, either as text written on the tag itself or as an address opening a page you have prepared.
Text on the tag works with no network, which matters in a garden, a cellar or a wood. An address allows pictures and audio, and needs a signal at every station.
Decide that before writing anything, because it changes what you write and where you can put the stations.
Which phones can play
One phone for the group is the arrangement that works. Everybody clusters round it, which is what you wanted anyway, and you have one device to test against.
Take NFC Tools. On iOS it requires an iPhone 7 or later running iOS 15.6 or later, and the app must be launched manually. Background reading is available from the iPhone XS and XR onwards.
Test the route on the actual phone, at the actual stations, before anybody plays. A station that reads on your phone at the kitchen table and not on theirs behind a downpipe is the normal way this fails.
Order cannot be enforced
A tag answers whoever taps it. If a player wanders past station five on the way to station two, station five will tell them everything it knows.
There is no lock on a tag that opens with progress, and building one would mean a page that tracks the group, which is a great deal of work for an afternoon.
The simpler answer is spacing. Put stations far enough apart, or out of sight of one another, that stumbling on them out of order is unlikely.
Or embrace it. A hunt where the clues can be found in any order and assemble into one answer is easier to build and harder to break.
Doing it outdoors
Rain gets in at the edges of a sticker, and a tag flat against a tree, a post or a wall reads poorly if there is metal behind it.
Use tags meant for outdoor use, mount them on something plastic or wooden, and mark each station visibly so nobody spends twenty minutes searching a hedge.
Collect them afterwards. A tag left on a tree is litter with an address on it.
Frequently asked questions
Should the clue be on the tag or online?
On the tag if any station might lack signal. Online if you want pictures or audio and every station has coverage.
Can I stop players finding stations out of order?
Not with tags alone. Space the stations out, or design a hunt where order does not matter.
Does everybody need a phone?
One phone for the group works better. It keeps people together and gives you a single device to test with.
What about rain?
Use tags specified for outdoor use and mount them off metal. Water gets in at the edges of a plain sticker.