Developer Documentation
This section contains technical documentation from reverse engineering the Huepar S120R-BT laser distance meter. The protocol was decoded by analyzing the official Android app and live device captures.
Documentation Structure
Section titled “Documentation Structure”This documentation follows the Diátaxis framework:
Explanation Understand how things work - protocol concepts, OEM ecosystem, and security analysis
Reference Technical specifications - BLE services, commands, response formats, and API endpoints
How-to Guides Practical guides for connecting to devices and capturing traffic
Quick Facts
Section titled “Quick Facts”| Aspect | Details |
|---|---|
| Protocol | LDMv1 (Laser Distance Meter v1) |
| Transport | BLE GATT over custom service 0xAE30 |
| Command Format | F1 prefix + command + checksum |
| Checksum | sum(bytes[1:]) % 256 |
| OEM | Longshuo Technology (龙硕科技) |
| App Framework | React Native / Hermes |
Analysis Sources
Section titled “Analysis Sources”| Source | Description |
|---|---|
com.pairlink.futian.huepar v2.6.004 | Decompiled Android APK |
| btsnoop captures | Live BLE packet analysis |
| Device testing | S120R-BT hardware validation |
Status
Section titled “Status”The core protocol is fully decoded:
- Device discovery and connection
- All measurement commands
- Settings and configuration
- History synchronization
- Continuous measurement mode
- Backend API endpoints