Audio capture and energy management daughterboard PCB for the Ambient project.

For more details, please refer to the daughterboard Git repository and the Ambient project README.

Overview

The Ambient project strives to provide a biodiversity monitoring platform built around an autonomous smart sensor node deployed in the wild.

Currently, the project focuses on birdsong recording and recognition for bird species classification.

The hardware and firmware project sources are provided as open-source (hardware: CERN-OHL-P-2.0 license, software: Apache-2.0 license) for anyone to build, improve and extend the platform.

In addition to the daughterboard, also provided under open-source licenses are:

• Mainboard
• Antenna PCB
• Zephyr-based firmware
• Arduino-based firmware

Main features of the daughterboard

• Energy management:
• Li-ion/LiPo charging circuit from photovoltaic cell with maximum power-point control (Consonance CN3791 controller), a variant exists for LiFePO4 (using Consonance CN3801 controller),
• solar and battery current and voltage monitoring (Texas Instrument INA3221 monitor),
• Audio capture:
• analog-to-digital converter with microphone input amplification and digital filtering (Texas Instrument TLV320ADC3101),
• analog audio wake-up circuit with high-pass filter and threshold detector.
• Magnetic reed switch for microcontroller reset

Daughterboard fabrication notes

PCB

Standard 2-layer 1.6mm stackup:

• 2 layers (front/back),
• 1.6mm thickness (not mandatory),
• 1oz copper,
• FR-4 dielectric,
• HASL finish.

No special requirements, any solder mask and silkscreen color.

Gerbers are provided but can be re-generated from the KiCad project.

Assembly

Recommended automated assembly for top-side only.

Manual assembly for bottom side:

• J3 and J9 connectors (through-hole).

Acknowledgment

This project has received funding from Université Côte d'Azur and CERN.