TinZr: A compact wireless ESP32-C3 platform for multi-modal physiological sensor integration and data acquisition

Figures

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  Fig. 1. TinZr pinout diagram showing the available GPIOs, communication interfaces, power rails, and key functional connectors.

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  Fig. 2. 3D model of the TinZr wearable enclosure illustrating the mechanical design used to enclose the PCBA and battery for wearable applications. The exploded view (left panel) shows the individual enclosure components, including the main enclosure, top lid, battery lid, TinZr Rev 5 PCBA, and 150 mAh Li-ion battery, while the assembled view (right panel) shows the fully assembled enclosure (length = 29.5 mm, width = 29 mm, and height = 20 mm). Dashed orange arrows in the exploded view indicate the assembly directions and relative placement of each component during enclosure assembly.

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  Fig. 3. Step-by-step illustration on how to assemble the TinZr Rev 5 board with the wearable 3D enclosure (panels A–C), following the steps described in Section 5.4. Panel D shows the fully assembled device (length = 29.5 mm, width = 29 mm, and height = 20 mm).

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  Fig. 4. Screenshot of the TinZr Communication Center Python-based GUI used for multi-device control over Wi-Fi, alongside a photograph of two TinZr devices (TinZrBlack and TinZrGold). Panel A demonstrates LED control at a low brightness setting (brightness level 20), while panel B shows the same devices driven at a high brightness setting (brightness level 150).

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  Fig. 5. IMU recordings during three scenarios; panel A, under no motion; panel B, during repetitive hand up-and-down motion at a frequency of 50 bpm; panel C, during repetitive hand up-and-down motion at a frequency of 100 bpm.

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  Fig. 6. Multi-modal physiological signals collected simultaneously. The ECG waveform, shown in blue, was acquired from a custom ECG front-end based on the MAX30001. Dual-wavelength PPG signals were acquired using a MAX30102 optical sensor, with the red PPG waveform shown in red and the infrared PPG waveform shown in black.