Rower Hardware
SmartRowerGauge — rowing telemetry module, ANT+ broadcast at 4 Hz
Overview
SmartRowerGauge is an indoor rowing telemetry device. It captures force, power and inertial data from a rowing machine and broadcasts the processed metrics wirelessly over ANT+ to the Garmin fitness ecosystem — watches, bike computers and head units.
The unit mounts on the rower and is powered by a rechargeable Li-Ion cell. It requires no wired connection to a display: every measurement leaves the unit over the air, and the SmartRower companion app renders live stroke telemetry from the same broadcast data.
Prototype Hardware
Key Features
- ANT+ at 4 Hz — Fitness Equipment device profile; no display wiring, no receiver dongle beyond a standard ANT+ head unit
- 24-bit Force Measurement — 24-bit strain-gauge force measurement sampled at 10 Hz
- Motion Sensing — 3-axis accelerometer at 40 Hz for stroke-rate calculation, ±2 / ±4 / ±8 / ±16 g
- Battery Powered — Rechargeable Li-Ion cell, charged over USB-C
- No Display Wiring — Every metric leaves the unit over the air; there is no wired data path
Key Specifications
| Parameter | Value |
|---|---|
| Radio | ANT+ broadcast at 4 Hz (Fitness Equipment device profile); Bluetooth for wireless firmware updates |
| Broadcast Interval | 4 Hz (every 250 ms) |
| Force Sensing | Strain-gauge force measurement, 24-bit resolution, 10 Hz sample rate |
| Motion Sensing | 3-axis accelerometer, ±2 / ±4 / ±8 / ±16 g, 40 Hz sample rate |
| Power | Rechargeable Li-Ion cell, charged over USB-C |
| Charging Current | [TBD - not published] |
| Enclosure | Custom 3D-printed, with a mounting clip for a standard rowing-machine rail |
Interfaces
The end product has exactly three interfaces and no other electrical interface — no headers, no test points, no debug or programming connector and no external sensor connector:
- ANT+ — telemetry broadcast at 4 Hz to fitness head units (Garmin ecosystem).
- Bluetooth — wireless firmware updates only.
- USB-C — battery charging.
Detailed Specifications (Preliminary)
Values marked [TBD] are unresolved. Where an operating or storage limit is marked estimated that is the source document's own qualification, not a measured limit.
Sensing
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Force Sensing | Strain-gauge force measurement at the handle | |||
| Force Resolution | — | 24 | — | bits |
| Force Sample Rate | — | 10 | — | Hz |
| Motion Sensing | 3-axis accelerometer | |||
| Accelerometer Range | ±2 / ±4 / ±8 / ±16 g | |||
| Accelerometer Sample Rate | — | 40 | — | Hz |
Electrical
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Battery Voltage | 3.7 | — | 4.2 | V (rechargeable cell) |
| Charging Current | — | [TBD - not published] | — | mA |
| Regulated Rails | [TBD - not published] | |||
| Timing Reference | [TBD - not published] | |||
| Current Consumption | — | [TBD] | — | mA |
Radio
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Telemetry Protocol | ANT+ — Fitness Equipment device profile | |||
| Transmit Interval | — | 4 | — | Hz |
| Wireless Updates | Bluetooth — firmware updates only | |||
Mechanical / Environmental
| Parameter | Min | Typ | Max | Unit |
|---|---|---|---|---|
| Overall Dimensions | [TBD - not published] | |||
| Weight | — | [TBD] | — | g |
| Operating Temperature | 0 | — | 50 | °C (estimated) |
| Storage Temperature | −20 | — | 70 | °C (estimated) |
| Humidity | Indoor use | |||
Ordering & Compliance
| Item | Status |
|---|---|
| Assembly | Hand-assembled prototype |
| Regulatory | Not certified — prototype use |
| ANT+ certification | Not submitted — broadcast-only use of a public device profile |
| Production / availability | [TBD] — no commitment is made |
Documentation
The draft product specification re-typesets this hardware's engineering documentation into the shared specification template, with a document-control block and the full specification tables. It is stamped as content not final on every page.
Companion software
The Android companion app renders this hardware's live broadcast: stroke rate, distance and power plots, per-stroke force curves and session history.
View the SmartRower app →Status
Prototype hardware, documented and characterised. Preliminary specifications subject to change.
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