Geophone Platform

Overview

In November 2017, I started writing my master thesis in the Computer Engineering Group at ETH Zürich. My thesis - officially titled "Event-based Geophone Platform with Co-detection" - is about developing a new, state-of-the-art networked sensor platform focusing on sensing micro-seismic activities to provide early warnings for natural hazard mitigation. Beside extensive research and collaboration with the Department of Geography at University of Zürich, my work included advanced hardware design from scratch and embedded software development.

After developing the first prototypes, initial field experiments were conducted which showed remarkably great results. Consequently, after finalizing every detail, the device went into production state, and currently 50 pieces were manufactured. I am extremely proud that a device which I developed and built from scratch within just 6 months were manufactured in those numbers and being deployed and used this summer in the Swiss mountains.

Media

In May 2018, the geophone platform was featured on SRF Einstein (Swiss TV show). The part of the episode, titled "Forschung extrem: Datensammeln im Permafrost" introduces the geophone platform that I've developed alongside with the wireless sensor network deployed and operated in the Swiss mountains.

Watch the video

Features

Major hardware features:

• Ultra-low power system design: as low as 29uA overall current drain from battery (including DC/DC conversion)
• Robust hardware design for high-alpine environment and noise-resilient circuit design
• Ultra-low power Cortex-M4 core microcontroller from the STM32L4 family
• Low-power radio module with BOLT
• Logging to SD card with FAT32 and exFAT file system support
• Omnidirectional geophone
• Ultra-low power, always-on triggering
• Dual-side (positive and negative) triggering
• High dynamic range, high precision triggering with hysteresis
• Independent positive and negative thresholds
• Switchable, dual-stage signal amplification for maximum efficiency and dynamic range
• Remotely configurable threshold values and amplification stage settings
• 26uA total triggering consumption with single-stage amplification at 3.0V
• 46uA total triggering consumption with dual-stage amplification at 3.0V
• High-precision 140dB SNR 24-bit ADC with integrated PGA
• Battery-operated with battery voltage monitoring
• USB and external power supply support
• Inertial measurement unit with triggering capabilities
• Temperature & humidity sensing
• Metal enclosure with IP67 rating and custom-designed mounting plate
• Custom, 3D-printed geophone clamp

Major software features:

• FreeRTOS Real-Time Operating System
• Self-customized RTOS kernel for ultra-low power consumption
• High precision (sub-millisecond) time synchronization mechanism
• Ultra-fast wakeup and sampling-launch: < 3ms
• Logging to SD card with FAT32 and exFAT support
• Configuration parameters stored on SD card
• Remote on-the-fly re-configuration
• Robust, fail-safe software design
• Custom bootloader for firmware updates
• Support for OTA (over-the-air) firmware update
• Self-test and self-monitoring features
• Detailed hardware-testing feature for production: manufacture, flash, connect to PC via USB and immediately see results of hardware-test to quickly identify possible manufacturing and/or component issues
• Advanced RTOS tracing support for debugging
• USB device support:
  • USB DFU (Device Firmware Upgrade) support: if bootloader needs to be upgraded
  • USB MSC (Mass Storage Class) support: SD card can be mounted directly to PC, without ejecting it from the device
  • USB CDC (Communication Device Class) support: for serial communication and command-line interface

Report

Please note that the file size of full report is approximately 19MB, thus it may take some time to download.

Read the report

Publications

Event-​triggered natural hazard monitoring with convolutional neural networks on the edge

How many climb the matterhorn? (Demo abstract)

Event-​triggered Geophone Platform for Co-​Detection of Seismic Events

Pictures

The prototype PCBs were manufactured with traditional green solder mask, but the production PCBs have matte black solder mask - which looks great with the electroless nickel immersion gold (ENIG) finish.