How Tailways actually works
Specifications and honest limits, for anyone deciding whether this is real engineering.
1 · Why not heart rate
A photoplethysmography (PPG) sensor, the kind in consumer wearables, needs consistent skin contact to get a clean signal. On a furred animal that means shaving a patch or fitting a tight chest strap, neither practical for daily wear.
Motion artefact from a dog's own movement also corrupts PPG far more than it does on a mostly-still human wrist. And a single heart-rate number is a weak, indirect proxy for emotional state on its own. We chose motion-based sensing because it's the more reliable signal for this problem, not the more convenient one.
2 · The sensor
A 24GHz FMCW (frequency-modulated continuous-wave) radar module, sampled continuously.
| Frequency | 24GHz FMCW |
| Range gates | 9, each tracked independently |
| Per-gate output | Motion energy, static energy |
| Sampling | Continuous |
3 · Classification
Rolling-window features (total motion energy, motion variance, stillness ratio, sudden-change count, and a breathing-rate proxy) feed a five-state classifier that also outputs a confidence score.
State transitions require sustained agreement across consecutive windows (hysteresis), which prevents flicker between adjacent states.
Per-dog baselines are learned over the first several days of wear, since a greyhound's stillness and a terrier's stillness are not the same signal.
4 · The intervention
Four ERM (eccentric rotating mass) vibration motors run rhythmic patterns at either a slow-breath pace or a resting-heartbeat pace.
It's a closed loop: the anxiety score is monitored throughout a session, and the session ends early if the score falls before the maximum duration is reached.
5 · Safety architecture
All limits below are enforced in firmware, not policy.
| Limit | Threshold | Action when hit | Recovery |
|---|---|---|---|
| {{ row.label }} | {{ row.value }} | {{ row.action }} | {{ row.recovery }} |
The safety monitor runs on the real-time core at the highest task priority in the system and cannot be pre-empted by any other process, including the classifier and all network activity. Safety is not a check that runs when there is time spare. It is the task everything else yields to.
Intensity levels
| Level | PWM duty | Intended for |
|---|---|---|
| {{ row.level }} | {{ row.duty }} | {{ row.use }} |
There are eight therapy protocols: Heartbeat Rhythm, Breathing Pulse, Spine Wave, Comfort Hold, Anxiety Wrap, Progressive Calm, Focus Pattern, Sleep Inducer.
6 · What we don't claim
- No medical or veterinary claim of any kind.
- No vital-sign measurement, motion and breathing pattern only, not heart rate.
- Any data shown states its sample size; nothing here has been validated at scale.
- Long-term effects of daily wear are still unproven.
7 · Who's building this
Tailways is built by Abdul Sattar, founder and chief architect. The firmware, the harness assembly, and the app are all his work. The first prototype ran for twenty-nine hours on a real dog before anyone else saw it. When you apply, he reads it. When the harness is fitted, it's fitted by the person who wrote the code running on it.
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