CM4

PorpDAQ

STM32 Based design data acquisition recorder for harbour porpoises. The system is based on a 40dB bandpass preamplifier (90Khz - 150kHz). Records WAV file at a sampling rate of 400 KHz (V1) and 500 KHz (V2) and stores them to a microSD card. The preamplifier was designed using TI's filter designer tool. Preamp output is passed to a summing amplifier to keep signals within 0 - 3.3V with a 1.65V bias. There's a few iterations of the DAQ from the initial prototypes to improved designs.

PorpDAQ has been designed to fit within a small multirotor UAV so current design weighs only 18g. PorpDAQ computes a 1024 point RFFT of incoming hydrophone signals and transmits signals within 90 - 150KHz over a UART Interface

Rev 1 Board

The initial version of the DAQ was based on a STM32F746 chip and had a 400 KHz sample rate and a 12-bit ADC with a SD card write speed of about 20mbps.

Rev 2 Board

Rev 2 board comes with some improvements namely the the use of the STM32H743 chip, USB-C for power with the addition of a full speed interface. 500 KHz sample rate, SD Card write speed of ~35 Mbps with a 16-bit ADC and better SNR. Also slightly smaller footprint

This repository mostly contains :

• Hardware designs for the both revisions (circuits were simulated in MultiSim and designs were made in UltiBoard and Kicad)
• Designs for the different prototypes used.
• A CM4-based design to integrate PorpDaq with a Pi4 Compute Module (WIP)
• 3D designed case for the Rev 1 board
• Low level drivers and firmware (bare-metal version and FreeRTOS version for Rev1 and FreeRTOS version for Rev2)

Note Rev2.1 now included as well.

• 3.3V regulator on Rev 2 used a switcher and wasn't running in low noise mode (oops!) so 2.1 now uses a low noise ADP7156 3.3V regulator

Structure

• Firmware: Contains Custom Board FreeRTOS firmware and STM32F7 discovery board FreeRTOS and bare-metal firmware. Also contains H747 Disco Board firmware. Please note bare-metal firmware currently has a UART TX bug preventing data from being transmmitted over the UART line.
• Hardware: contains various designs and schematics for the board designs. Rev 1 design is named board_100pin while Rev 2 design is named h7_board.

Citation (Bibtex)

@article{Babatunde2020, doi = {10.3390/s20216064}, url = {https://doi.org/10.3390/s20216064}, year = {2020}, month = oct, publisher = {{MDPI} {AG}}, volume = {20}, number = {21}, pages = {6064}, author = {Daniel Babatunde and Simon Pomeroy and Paul Lepper and Ben Clark and Rebecca Walker}, title = {Autonomous Deployment of Underwater Acoustic Monitoring Devices Using an Unmanned Aerial Vehicle: The Flying Hydrophone}, journal = {Sensors} }

License

MIT License Copyright 2020 Daniel Babatunde