01WEAR
Wear the tracker.
Trackr records your heart rate, sleep and movement throughout the day.
OPEN-SOURCE HEALTH TRACKER
A tracker for
the app
you build.
Trackr is a screenless health tracker. Build your own app with help from Claude or ChatGPT, and decide how your data is used.
FIG. 001 — TRACKR
Screenless sensor.
Woven wristband.
RENDER / CARBON BLACKWoven wristband.
Open-source firmware Local data storage Build your own app
01 / THE IDEA
Build the app
you actually want.
A sleep journal with room for notes. A training log that puts heart rate first. Or just your steps on one screen.
Trackr gives you access to your health data and the tools to build with it. You choose the features, the layout and where the data lives. Change the app when your needs change.
Explore the app examples02 / THE HARDWARE
Heart rate. Sleep.
Daily movement.
A compact sensor in a woven band,
with no screen to check.
TRACKR
Screenless sensor. Woven band.CARBON BLACK
WHAT IT TRACKS
Heart rate
See your heart rate at rest and during activity.
Heart rate variability
Follow your HRV overnight and around the moments you choose to measure.
Sleep patterns
Review sleep duration and timing in the app you build.
Daily movement
Keep track of steps and active time throughout the day.
Calorie burn
Get an estimate of active and resting calories for each day.
Your trends
Compare your readings over days and weeks, in a format that makes sense to you.
Final specifications may change before launch.
03 / BUILDING YOUR APP
Same readings.
Six different apps.
Trackr records heart rate, sleep and movement. What you make of them is up to you: a dream diary, a meditation log, a training plan, or a game where a good night’s sleep restores your hero’s health.
SIX APPS BUILT ON THE SAME READINGS.
The sleep data tells one story. Your dreams tell another.
- A sleep score, total sleep and REM estimate for each night
- Dream entries linked to the night they happened
- Your own notes and mood tags beside the readings
AN EXAMPLE PROMPT
“Build luna in midnight purple and lavender. Give each night a sleep score, total sleep and estimated REM. Link those readings to a dream diary where I can write what I remember, add a mood and browse previous nights.”
TRY THE APP
9:41
luna✦SLEEP & DREAMS
LAST NIGHTA night
10:32 PM – 6:14 AM
A night
to remember.
10:32 PM – 6:14 AM86SCORE
Total sleep7h 42m
REM estimate1h 54m
Inside your nightSTAGE ESTIMATES
Light4h 30mDeep1h 18mREM1h 54m
Sample sleep estimates and an illustrative score. Dream entries are written by you.
APP EXAMPLE / luna
Choose a night, compare its readings, then write or edit a dream.
Example apps with sample readings and illustrative scores. Changes reset when you switch apps or reload.04 / HOW IT WORKS
From tracker
to your own app.
Three steps,
from recording data to building software.
02CONNECT
Connect to the data.
The connection documentation and starter code show you how to read data from the tracker.
03BUILD
Build and test your app.
Ask Claude or ChatGPT to help write the screens and features you want. Test the result, then adjust it as you use it.
05 / WHY OPEN SOURCE
Open source,
for practical reasons.
01 — OPEN SOURCE
Code you can inspect.
The firmware and app starter code will be published, so you can see how the device works and modify the parts you need.
02 — DATA OWNERSHIP
Keep data on your phone.
Your app can store health data locally. You decide whether to connect other services, rather than relying on a required cloud account.
03 — LOWER OVERHEAD
A smaller software bill.
Maintaining a large companion app adds cost. We focus on the hardware and open tools, to keep the device affordable.
FREQUENTLY ASKED QUESTIONS
The details.
What it is, how it works,
and when you can get one.
What exactly is Trackr?
A screenless fitness tracker that works with software you build yourself. It records heart rate, heart rate variability, sleep and daily movement, estimates calorie burn, and leaves the app to you. Trackr isn’t on sale yet, and the product images on this page are renders.
Are the apps shown here included?
They’re examples of what you can build, running on sample data. Trackr will come with starter code you can adapt with Claude or ChatGPT. Your finished app can have its own name, layout and features.
Do I need to know how to code?
Some familiarity will help. Trackr will come with starter code, connection documentation and sample data that you can use with Claude or ChatGPT. These tools can help write the app, but you’ll need to test it. More complex features may need a developer.
What does open source mean here?
The firmware, connection documentation and app starter code will be published, so you can inspect and modify them. We’re still settling the licence and how much of the hardware design to document.
Where would my health data live?
Your app stores health data on your phone, with no required blnk.SLATE cloud account. You choose whether to connect other services. You can use sample data when building with AI; there’s no need to upload your health records. Security depends on how the app is built and configured.
When can I get one?
We haven’t set a launch date yet. Join the waitlist and we’ll email you as soon as there’s news.
TRACKR WAITLIST
Be first
in line.
Sign up for development updates and launch news for Trackr.
OPEN-SOURCE HEALTH TRACKINGTRACKR — BY blnk.SLATE