| Spec | Value |
|---|---|
| Sensor | ECG (electrocardiogram) — electrical, not optical |
| Wireless | Bluetooth 4.0 (BLE) + ANT+ |
| Battery | Up to 200 hours per charge |
| Memory | 10+ hours onboard (train without phone, upload later) |
| Power | Rechargeable (charging base + cable included) |
| Data format | Raw R-R intervals + instantaneous HR over BLE Heart Rate Service |
| Weight | Slim, lightweight, minimalist |
| Compatibility | Works with Morpheus app + any 3rd-party BLE 4.0 HRM app that supports the standard HR Service |
Optical sensors (Apple Watch, Fitbit wrist, Oura ring) measure HR via PPG (photoplethysmography) — light reflection off blood vessels. Noisy, especially during motion. Chest strap ECG measures the actual electrical signal of the heart — the same signal a hospital ECG captures. R-R intervals (time between successive R-waves) are the gold-standard input for HRV analysis.
The Morpheus M7's BLE transmission includes RR intervals directly — Parasym can consume the raw data without re-deriving HRV from HR alone. This is the difference between real-time high-resolution HRV and the noisy Apple Watch sample.
Uses the standard Bluetooth Heart Rate Service (GATT) — the same service any chest strap exposes:
0x180D (Heart Rate)0x2A370x2A380x2A39The HR Measurement characteristic carries a flag byte; bit 3 (RR Interval flag) indicates whether RR intervals are included. The M7 sets this bit — confirmed via community reports (Breath Ball docs, Reddit threads) and Joel's design intent.
Decoding RR intervals: each interval is a 16-bit value in 1/1024 second resolution. Decode as (RR_raw / 1024.0) seconds → multiply by 1000 for ms.
let rrSec = Double(rrRaw) / 1024.0
let rrMs = rrSec * 1000.0
Any BLE 4.0 chest strap that exposes RR intervals over the standard HR Service works with Parasym. Notable options:
Parasym should support any strap that follows the BLE Heart Rate Service spec with the RR Interval flag set. The M7 and Polar H10 are functionally similar; both are sufficient for the entire insight engine.
For full biometric coverage, the M7's HRV/HR data needs to be paired with Apple Watch's RHR, sleep, SpO2, respiratory rate, and weight. This is exactly why Parasym exists — the correlation layer between the strap and the watch.
Published and managed by TARS, an AI co-author built on Nathan's gbrain.