A Non-Invasive, Self-Charging Telemetry System for Rats: Real-Time Preprocessing and Compression of Multi-Modal Physiological Data for BLE Transmission

Monitoring the vital signs of laboratory animals is essential for research integrity and animal welfare(1)(2). However, conventional telemetry devices are often cost-prohibitive(3) and require invasive surgical implantation, which induces stress and complicates recovery (4)(5). This paper introduces a novel, non-invasive wearable device designed for the continuous monitoring of animal movement, heart rate, and blood oxygen levels. Built on the ESP32-S3 microcontroller and housed in a 3D-printed enclosure, the system utilizes magnetic resonance wireless charging to operate through up to 2.5 cm of non-conductive container material(6), eliminating the need for battery replacement or handling the animal. Integrated sensors include an ECG, pulse oximeter, a temperature sensor, and an ISM330DHCX inertial measurement unit for activity tracking. Data is transmitted via Bluetooth Low Energy (BLE) using Tamp(7)(8), a low-memory, DEFLATE-inspired lossless compression library to optimize bandwidth. The compression has a 1.49x compression ratio and a 100% success rate. This system offers a cost-effective and low-stress alternative to invasive telemetry, enabling long-term, autonomous data collection in biological research