Handover Document: Web-Based Multimeter (BLE)

Project Overview

Purpose:
Provide a web-based platform that connects to digital multimeters via Bluetooth Low Energy (BLE), decodes readings in real-time, and displays measurements and graphs via a modern JavaScript (and intended browser-based) frontend.
Features Implemented:
- BLE connection and notifications from various multimeter models using JSON configuration.
- Parsing/decoding of obfuscated BLE packets (with per-model config for digits, icons, and units).
- Smart, quiet output (value/mode changes only) and verbose debug option.

BLE Connection:
Uses bleak (Python) for managing BLE device connections, subscribing to measurement notifications.
Decoder Logic:
- Hex packets are XOR-unobfuscated and bits are mapped to 7-segment digits and icons.
- All protocol/mapping details are externalized into a model-specific JSON file.
Output Control:
Console logging behavior governed by config (log_level: "info", "lite", "debug", "warning").

JavaScript-based Web App
- Intended to connect to BLE multimeters from within the browser using Web Bluetooth API.
- Real-time value/graph display, modes, and protocol mapping as pioneered in Python version.

Purpose:
Allows support for many DMMs by abstracting BLE UUIDs, XOR keys, digit/icon mapping, and output units.
Key Sections:
- modes: Hex notification → Mode name mapping.
- digit_table: Segment-to-digit/character mapping for 7-segment display values.
- icon_regions/icon_tables: Define where in each packet icons are encoded, and map them by bit to human-readable units/symbols for each mode.
- units: Which measurement unit to append for each mode.
- log_level: Controls verbosity and debug output behavior.
How To Extend:
New models = add or clone config files, adjust keys/tables as needed.

Receive hex packet via BLE.
Unobfuscate using per-model XOR key.
Convert to bit string, optionally reverse bits.
Extract display digit region and decode using digit table.
Extract icon region for mode, map with icon table (mode-specific if needed).
Print/log/output only when value changes (or in full debug mode).

Lite/Info:
- Prints only on mode change or display value change.
Debug:
- Prints all decoded notification info and raw packet, useful for troubleshooting or mapping new modes/packets.
Icons/units: Mode-specific filtering via JSON prevents irrelevant or noisy output.

Create new JSON file, copying existing structure.
Update modes section: Map each button/mode-change code to correct label.
Set the per-model xorkey.
Tune digit_table and icon_tables as observed from the meter’s display.
For weird/new icons, update/add mode-specific icon tables.
Test/adjust output by flipping log_level between "debug" and "info" as needed.

Python backend is functional with smart value change tracking.
Config system is robust (per-model, per-mode handling, adjustable log level).
Output filtering matches DMM UI/UX norms.
Ready for:
- Port to JavaScript/Web (Web Bluetooth API offers similar notification pattern).
- UI/UX work for live digital/graph display.

Need more real-world per-model packet captures for corner cases (e.g., rare icons/units).
Front-end UI/JS integration.
(Optional) Add project documentation for users on mapping their own meters and sharing JSON configs.
Possible protocol edge-cases (multi-byte icons, decimal quirks) to handle with future test cases.

Lead (handover from): [Your Name/Username]
GitHub/Repo: [insert when live]
Suggest further reading:
- Web Bluetooth API docs (MDN)
- bleak Python BLE library

To continue:

Study JSON config and its reference file.
Run Python script, flip log levels as needed, test/observe.
For web: port BLE scan/notify and decoding tables to JS (all logic is model/config-driven).
Add, update, or share meter profiles by modifying JSON.