Case Study
LucaPaws
An app that turns a spare Apple Watch into a health tracker and ID tag for my dog, and helps plan his first flight abroad.
Submitted to App Review on October 3, 2026.
App
Luca Paws
Role
Solo Designer & Developer
Platform
iOS · watchOS
Status
In App Review
Impact at a glance
Built in four days. The real test is in January.
$0 hardware
The sensor is an old Apple Watch I already had.
19 steps
Trip tasks, dated backward from the flight.
No data collected
Nothing leaves the phone.
The problem
Luca is flying to Guatemala in January
Luca is a 40 lb mixed breed with sensitive skin and ears. He's too big for the cabin, so he'll fly in the hold. Getting him there and back means vet visits, USDA paperwork and CDC rules, and some steps can't be fixed once you leave.
I also wanted to know if he was itching more on the trip than at home. Dog health collars exist, but they cost money every month and don't help with travel. I had an old Apple Watch in a drawer, so I used that.
What I left out: live alerts from the hold, GPS tracking, diagnosis and accounts. Researched entry rules exist only for Guatemala; other countries get the US exit steps and a link to USDA. None of the rest was needed for this trip.
Trip
Days until the flight and anything that needs attention.
Above normal
Says what to check. Never a diagnosis.
His usual
Today compared with his last 14 days.
Trip
Days until the flight and anything that needs attention.
Above normal
Says what to check. Never a diagnosis.
His usual
Today compared with his last 14 days.
The watch
An Apple Watch on a dog collar
Luca's watch
Old Series 8, on its own collar
My iPhone
Stores everything. Nothing goes online.
My watch
Series 11, on my wrist
This works for me, but it's also the biggest product risk. The people most likely to have a spare watch are the ones who upgraded and wear a new one, which is exactly when the phone can't reach both.
The watch screen is also his ID tag. It shows his name and my number in English and Spanish, with buttons to call or WhatsApp me.
Labeling
Teaching the app what scratching looks like
There's no public data for dogs scratching, licking or eating, so I label it myself. After about two weeks of labels, I can train a model on them.
Progress
Days labeled out of 14.
Sessions
Starting a walk also starts the watch.
Tap or hold
Tap for quick things, hold for longer ones.
Progress
Days labeled out of 14.
Sessions
Starting a walk also starts the watch.
Tap or hold
Tap for quick things, hold for longer ones.
Health
Tracking itching
Itching is Luca's main issue, so the app tracks it closely. It splits scratching into left ear, right ear and body, and points it out when one ear gets most of it.
Baths, food changes and flea treatments show up on the chart, so it's easy to see what changed before the itching did.
What to check
A next step, not a verdict.
Diary on the chart
Baths and food changes as dashed lines.
Travel vs. home
The question the trip is meant to answer.
What to check
A next step, not a verdict.
Diary on the chart
Baths and food changes as dashed lines.
Travel vs. home
The question the trip is meant to answer.
Trip
A checklist that counts back from the flight
Pick a country and dates, and the app lists every step with its deadline and source.
28+ days before
Rabies shot
Microchip first, or it doesn’t count
Before leaving
US rabies certificate
Can’t fix later
10 days before
Health certificate
Vet signs, USDA endorses
Jan 8
Fly to Guatemala
Before return
CDC Dog Import Form
Guatemala is high-risk for rabies
Jan 24
Fly home
In testing with sample data, it flagged a rabies shot that would expire four days before the flight home.
Dated rules
Each rule shows when it was last checked.
Timeline
Where you are between home and the flight.
Can't fix later
The shot runs out before the trip home.
Dated rules
Each rule shows when it was last checked.
Timeline
Where you are between home and the flight.
Can't fix later
The shot runs out before the trip home.
Design decisions
An old watch over a custom collar
A custom collar means building hardware and getting FCC approval. The watch already records motion, and I already owned it.
His normal over general norms
The question is whether he changes on the trip, so the app compares him with his own last 14 days.
Flags over diagnoses
A collar can see that something changed, not why. The app says “above his normal” and suggests a vet.
On the phone over the cloud
No account or server means nothing to keep running, and no one else’s health data on a server to protect.
Screens
What's next
After collecting data
1 · October
Collect labels
Put the watch on Luca and label meals, drinking and scratching for about two weeks.
Done when20 to 50 labels for each behavior.
2 · November
Train a model
Train on his labels in Create ML so the app can count behaviors on its own.
Done whenIts counts match what I saw on sessions it wasn’t trained on.
3 · December
Test the ID tag and crate
Hand the watch to strangers. Decide on a crate sensor once the airline answers.
Done whenThree strangers reach my phone in under 60 seconds.
4 · January
The trip
Fly to Guatemala and back. Log a daily check and compare travel days with home.
Done whenEvery document on time, a check logged every day.
5 · February
Decide
Look at the trip data and decide whether to build this for other dog owners.
Done whenA clear yes or no, based on the data.
If it becomes a product
Where it fits
| No new hardware | Health tracking | Travel paperwork | Crate in the hold | |
|---|---|---|---|---|
| Fi | – | ✓ | – | – |
| Invoxia, PetPace | – | ✓ | – | – |
| Passpaw, Travel Ready Pets | ✓ | – | ✓ | – |
| Luca Paws | ✓ | ✓ | ✓ | Planned |
I wouldn't compete with Fi on behavior tracking; they have years of data. The gap is the combination. The free trip planner brings people in. Who pays is still open: per trip, crate sensor rental, or pet relocation companies. Fixing sync for two-watch owners comes first either way.
Limits
What I don't know yet
It's one dog, and most of it hasn't been tested in real life yet. The model isn't trained, and the airline might not allow the watch in the hold.
Hola, soy Luca.