# CBB Project Brief: Chronograph BLE Integration Broker
**Status:** Concept
**Destination:** ScopeDOPE feature (sensor-integration module within the ScopeDOPE product; stays in the `ScopeDOPE/` namespace)
**Tier:** 2 — Strong Candidate
**Classification:** Internal — Confidential
**Version and date:** see Revision Control Block at the end of this document

---

## Summary

A ScopeDOPE™ module (and optionally a standalone app) that connects to Bluetooth-enabled chronographs — Garmin Xero C1 Pro, LabRadar LX, ProChrono Bluetooth — and automatically imports velocity strings into ScopeDOPE sessions. (MagnetoSpeed devices are wired-only and are handled, if at all, via file/cable import — see Supported Devices.) Manual muzzle velocity entry is one of the most friction-heavy parts of any ballistic workflow, and errors in MV data directly corrupt DOPE accuracy. This module eliminates manual entry entirely, captures SD/ES automatically, and feeds clean velocity data into the ScopeDOPE ballistic engine in real time.

---

## Problem Statement

Accurate muzzle velocity is foundational to every ballistic solution. A 20 FPS error in MV produces meaningfully wrong solutions at 500+ yards. Every serious precision rifle competitor should be using a chronograph, and many do — but the data stays in the chronograph, disconnected from the shooter's ballistic app.

Current workflow:
1. Shoot through chronograph
2. Look at chrono display or phone app
3. Mentally note average MV, SD, ES
4. Open ScopeDOPE (or other app)
5. Manually type the MV value
6. Hope you transcribed it correctly

Every step after #2 is error-prone and unnecessary. BLE exists on all modern chronographs. The data is already available — it just isn't flowing to the right place.

Existing chrono apps (Garmin Connect, Magnetospeed's own app) display velocity strings but don't integrate with ballistic apps. They're data silos. ScopeDOPE with a chrono integration is the only ballistic tool that closes this gap.

---

## Supported Devices (Target List)

**Priority 1 (BLE):**
- **Garmin Xero C1 Pro** (~$449; verified 2026-06-09) — largest market share among PRS/NRL22 competitors. BLE. Garmin Connect ecosystem. *(Note: Garmin has since released the Xero C2 Pro at ~$700 — evaluate as an additional target.)*
- **Competition Electronics ProChrono Bluetooth** (~$120) — entry-level, large install base. BLE.

**Priority 2 (BLE):**
- **LabRadar LX** (~$599.95; verified 2026-06-09) — Doppler-based, premium, common among serious competitors. The LX is the current-generation device (it supersedes the original LabRadar). BLE.
- **Caldwell Ballistic Precision** — BLE.

**Wired (non-BLE) — file/cable import only, NOT a BLE target:**
- **MagnetoSpeed Sporter (~$75–180) and V3 (~$180–400)** — barrel-mounted. **MagnetoSpeed devices are wired (XFR cable), not Bluetooth** — there is no "Sporter BT" or "V3 BT." They cannot be a live-BLE auto-import source; support them, if at all, via file/cable import as a separate (lower-priority) path. *(Correction 2026-06-09: an earlier version incorrectly listed MagnetoSpeed BT models as Priority-1 BLE targets.)*

---

## Product Concept

### Core Features (v1.0)

**Device Connection**
- BLE device scan and pairing (standard iOS/Android BLE flow)
- Automatic reconnect to previously paired device
- Connection status indicator in ScopeDOPE session UI

**Live Velocity Capture**
- As shots are fired, velocity readings appear in real time in the session UI
- Running SD and ES displayed live
- Accept or reject individual readings (flag fliers before they corrupt the average)

**Session Integration**
- At session close: "Use average MV from chrono? [48 readings: 2,986 FPS avg, SD 8.2]" — one-tap confirmation
- MV value populated automatically into the session's ballistic solution
- Full velocity string saved with the session (viewable in web companion)
- Individual readings exportable as CSV

**Cold Bore Shot Handling**
- "Mark as cold bore shot" flag for the first reading of the session (excluded from MV average for DOPE purposes, logged separately for cold bore delta analysis)

### v2.0 Features
- Velocity string visualization (chart of shot-to-shot velocity over the session)
- Load correlation: link velocity string to a Cold Bore Load recipe (Brief #01) for SD/ES tracking by powder lot and charge weight
- Export velocity string to .dope file's optional `velocity_string` block
- Multi-session MV trend: "Your MV has dropped 12 FPS over 800 rounds — barrel wear indicator"

---

## Target User

Any ScopeDOPE user who owns a BLE-capable chronograph. Market penetration estimate: 40–60% of serious NRL22/PRS competitors own a chronograph; of those, a large share own a BLE-capable model (Garmin Xero C1 Pro, LabRadar LX, ProChrono Bluetooth are all BLE; MagnetoSpeed, though popular, is wired-only).

The integration is especially valuable for:
- High-volume shooters testing multiple loads (need MV per load, not per session)
- Competitors who switch ammo lots (each new lot gets a new MV baseline)
- Cold Bore Load users correlating load variables with velocity data

---

## Revenue Model

**Included in ScopeDOPE** at no additional charge. This is a depth feature — it makes ScopeDOPE more valuable to users who own a chrono and creates a compelling purchase reason for users who are considering buying one.

**Indirect value:**
- Garmin Xero C1 users who want BLE integration with their ballistic app currently have no option. This makes ScopeDOPE the answer to "what app works with my Garmin chrono?"
- Partnership opportunity: Garmin Xero product page linking to ScopeDOPE as a compatible app (requires reaching out to Garmin's Xero product team)

---

## Strategic Fit with CBB / ScopeDOPE

The chrono integration deepens ScopeDOPE's sensor ecosystem alongside WeatherFlow (atmospheric data) and the Niimbot printer (label output). The pattern is: ScopeDOPE is the hub, hardware devices are spokes. Every additional hardware integration makes ScopeDOPE harder to displace and harder for a competitor to replicate quickly.

**Acquisition signal:** A ballistic app with established BLE integrations to multiple hardware categories (weather sensors, chronographs, rangefinders, printers) is a platform. It's not just an app.

---

## Competitive Landscape

| Product | Garmin Xero BLE | LabRadar LX | ProChrono BLE | Auto-populates MV | DOPE integration |
|---|---|---|---|---|---|
| Applied Ballistics Mobile | ✗ | ✗ | ✗ | ✗ | ✗ |
| Hornady 4DOF | ✗ | ✗ | ✗ | ✗ | ✗ |
| Garmin Connect | ✓ | ✗ | ✗ | ✗ | ✗ |
| LabRadar app | ✗ | ✓ | ✗ | ✗ | ✗ |
| **ScopeDOPE** | **✓** | **✓** | **✓** | **✓** | **✓** |

No competitor integrates chronograph data with a ballistic/DOPE workflow. This is uncontested whitespace.

---

## Technical Overview

**Platform:** ScopeDOPE module (Android + iOS)

**BLE integration approach:**
- Garmin Xero C1 Pro: Garmin Connect IQ SDK + Bluetooth Low Energy. Garmin has a Connect IQ developer program (free registration). The Xero C1 Pro exposes a BLE service for live data streaming. Requires reverse-engineering the characteristic UUIDs or working with Garmin's developer program.
- ProChrono Bluetooth: BLE. Entry-level device with a large install base; community BLE documentation exists; CBB has experience with similar BLE reverse-engineering (Niimbot, WeatherFlow).
- LabRadar LX: BLE. The LX's BLE interface is the integration target. Doppler data format adds complexity vs. a simple velocity-string device.
- MagnetoSpeed (wired, non-BLE): no BLE path. If supported, only via XFR-cable/file import — out of scope for the live-BLE module.

**Data flow:**
```
Chronograph (BLE) → ScopeDOPE BLE manager → Velocity reading event
    ↓
Session velocity buffer (live list of readings)
    ↓
Session close → MV average calculation → Auto-populate session MV field
    ↓
Full velocity string saved to session record (optional .dope extension block)
```

**Key challenges:**
- Garmin Xero BLE protocol: may require developer agreement with Garmin
- LabRadar BLE: more complex data format, Doppler-derived velocity
- Background BLE on iOS: Apple restricts background BLE; need to handle app backgrounding gracefully
- Multiple simultaneous BLE connections: some users have both a weather sensor and a chrono connected

**Complexity estimate:** Medium. Each device requires individual BLE protocol research. Garmin is the highest-priority and likely most complex. ProChrono Bluetooth is simpler. Estimated 4–8 weeks per device implementation.

---

## Go-to-Market

**Garmin Xero partnership angle:** "ScopeDOPE integrates with Garmin Xero C1 — the only ballistic app that does." Pitch to Garmin's partner program and request listing on the Xero C1 product page as a compatible app.

**Community announcement:** "ScopeDOPE now pulls live velocity from your Garmin Xero / Magnetospeed — no more manual MV entry." Post on Sniper's Hide and NRL22 Facebook Groups.

**App Store update:** Feature the integration prominently in the update description. App Store ranking benefits from new features described in update notes.

---

## Success Metrics

| Metric | 6-month | 12-month |
|---|---|---|
| ScopeDOPE users with chrono connected | 15% | 30% |
| Sessions with auto-populated MV (vs manual) | 20% | 40% |
| Garmin Xero C1 partnership inquiry sent | ✓ | Response received |
| Devices supported | 2 | 4 |

---

## Risks & Mitigations

| Risk | Likelihood | Mitigation |
|---|---|---|
| Garmin requires formal developer agreement with restrictive terms | Medium | Reverse-engineer BLE protocol as fallback (legally permissible for interoperability) |
| BLE protocol changes in firmware update break integration | Medium | Version-check at connection time; graceful degradation if protocol unknown |
| LabRadar BLE protocol is poorly documented | High | Start with Garmin + Magnetospeed; add LabRadar as v2.0 |
| iOS background BLE limitations affect live capture | High | Require app to be foregrounded during chrono session; document this limitation clearly |

---

## Resource Requirements

- 1 developer (Jason) — 6–10 weeks for Garmin Xero C1 Pro + ProChrono Bluetooth (2 BLE devices)
- Garmin Connect IQ developer registration: free
- Test hardware: Garmin Xero C1 Pro (~$449), ProChrono Bluetooth (~$120) — required for testing
- No new infrastructure

---

## Recommended Timing

ScopeDOPE v2.0 or later. Not a launch feature but a meaningful depth feature for the first major update after launch. Prioritize after the barrel lifecycle tracker (Brief #05) since the tracker has lower implementation complexity. Garmin Xero integration is the highest-value single device to target first.

---

## Open Questions

- Does Garmin's Xero developer program require revenue sharing or exclusivity? Recommendation: investigate before committing; if terms are onerous, proceed with BLE reverse-engineering.
- Should velocity string data be stored in the .dope file or in a separate sidecar file? Recommendation: optional block within .dope — add to spec as .dope v1.1 extension.
- Is LabRadar worth the implementation complexity at v1.0? Recommendation: no — implement Garmin and Magnetospeed first, add LabRadar based on user demand.

---

## Document Control

| Field | Value |
|---|---|
| **Document owner** | `jschwefel@coldboreballisticsllc.com` |
| **Classification** | Confidential (03_-_Confidential/) |
| **Location** | `OneDrive/ScopeDOPE/03_-_Confidential/Product_Strategy/CBB_BRIEF_07_CHRONOGRAPH_BLE.md` |
| **Cross-references** | `CBB_PROJECT_BRIEFS_TOC.md` |
| **Created** | 2026-06-02 |
| **Last updated** | 2026-06-09 |
| **Next full review due** | 2027-06-02 |

---

## Revision Control Block

| Rev | Date | Changed By | Reviewed By | Approved By | Summary |
|-----|------|------------|-------------|-------------|-------|
| 0.9 | 2026-06-02 | jschwefel | — | — | Initial release |
| DRAFT | 2026-06-09 | Claude (Opus 4.8) | — | — | Removed header version number (→ Status/Destination + revision-block pointer); added Destination tag (ScopeDOPE feature); applied ™ to first use of ScopeDOPE. FACT CORRECTIONS (verified 2026-06-09): Garmin Xero C1 Pro $599→~$449 (and noted the new Xero C2 Pro ~$700); LabRadar → LabRadar LX ~$599.95 (current generation). MagnetoSpeed corrected from "Sporter BT / V3 BT (BLE)" to wired-only (XFR cable — no Bluetooth product exists) and demoted out of the BLE device list into a wired/file-import note; promoted ProChrono Bluetooth as the actual Priority-2 BLE target; updated competitive table, tech-overview, and test-hardware accordingly. |
