# Empatica E4 wristband: decoding BLE telemetry

> Empatica E4 wristband work reconstructs the device's BLE telemetry flow and provides a local recorder and decoder for accelerometer, skin temperature, electrodermal activity, and raw photoplethysmogram data. It documents GATT services and packet layouts, preserves raw packets, and writes decoded sensor readings to CSV.

- Type: Case study
- Targets: Protocol
- Category: Independent reconstruction cases
- Relationship: Independent reconstruction project
- Sources reviewed: 2026-11-08
- Added to the catalog: 2026-11-08
- Original resource: <https://github.com/Vijtus/empatica-e4-local>
- Primary source: <https://github.com/Vijtus/empatica-e4-local/blob/1c7a2a0900df503081c6d22d4790d2bfbb345bfc/README.md>
- Catalog page: <https://awesomerea.org/resources/empatica-e4-local-case/>
- Record JSON: <https://awesomerea.org/resources/empatica-e4-local-case/record.json>
- Chinese version: [简体中文](https://awesomerea.org/zh/resources/empatica-e4-local-case/index.md)

## Requirements & limits

- **Prerequisites:** An owned Empatica E4 wristband and Bluetooth are required.
- **Prerequisites:** Python 3.11 or newer is required; the launcher installs bleak and pyusb on first run.
- **Limits:** The PPG packing is tentative, and its original packet bytes are preserved for later decoding.
- **License:** MIT license.

## Primary sources

1. <https://github.com/Vijtus/empatica-e4-local/blob/1c7a2a0900df503081c6d22d4790d2bfbb345bfc/README.md>
2. <https://github.com/Vijtus/empatica-e4-local/blob/1c7a2a0900df503081c6d22d4790d2bfbb345bfc/help/03_how_we_decoded_the_wristband.md>

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## About this entry

The description was reviewed against primary sources.
Original editorial content: MIT. Linked projects, papers and assets retain their own rights and licenses.