Version 3.3.4

This release:

• Additional license information included for all utilized libraries.
• Repository prepared for use with Zenodo to register a DOI.

Version 3.3.3

This release:

• Minor fix to increase sample interval maximum range from 60 to 10080 minutes.

Version 3.3.2

This release:

• Minor fix to standardize size of sampleInterval in SBD MT struct/union to uint16_t, allowing for sampling interval durations greater than 255 minutes.

Version 3.3.1

This release:

• Added compatibility changes for RockBLOCK hardware revision v3.F.

Version 3.3.0

This release:

• Minor revision to PCB design (v3.1) resulted in a smaller size.
• PCB dimensions and hole patterns standardized to metric.
• New parametric 3D-printed case.
• Recreated schematic using new library components.
• Continued standardization of code with Cryologger AWS repository.
• Additional code commenting and cleaning.
• Code prepared for 2023 Amundsen Expedition deployments.

Version 3.2.0

This release:

• Replaced deprecated LSM6DS3 + LIS3MDL IMU with LSM303AGR accelerometer + magnetometer.
• Implemented new min/max calibration for LIS2MDL magnetometer tilt compensation.
• Began standardization of code with Cryologger AWS repository.
• Prepared code for deployment in Grise Fiord, Nunavut.
• Additional code commenting and cleaning.
• Adapted 3D-printed case from v1.0 for v3.x circuit board.

Version 3.1.0

This release includes a number of improvements and bug fixes for version 3.0 of Cryologger iceberg tracking beacon (ITB), which was initially deployed in the Canadian Arctic during the 2021 Amundsen Expedition.

• Improved assessment of GNSS message validity for ensure RTC date and time synchronization is reliable.
• Simplified RTC alarm logic to default to daily transmissions in the event of multiple transmission failures.
• Resistor divider increased to 10MΩ + 1 MΩ to allow for a wider range of battery voltages (6.0 V - 36.0 V).
• RTC alarms limited to daily to prevent the accidental setting of alarms far in the future.
• Dedicated ADC tab including code to manually adjust offset and gain values.
• Code prepared for 2022 Milne Fiord epishelf lake deployments.

Version 3.0.0 - Initial Release

This is the initial release of Version 3.0 of Cryologger iceberg tracking beacon (ITB), deployed in the Canadian Arctic during the 2021 Amundsen Expedition. This version builds on the success of v2.0 and while still based on the Adafruit ecosystem of components, includes several improvements to the overall design, including:

• A custom PCB carrier board was designed to greatly simplify the assembly process.
• The DS3231 real-time clock (RTC) was removed in favour of the SAMD21's internal RTC for all timekeeping and alarm functionality with periodic time synchronization with the GPS.
• 3.3 V power is now provided directly from a Pololu 3.3 V step-down voltage regulator, bypassing the Feather M0's onboard AP2112 LDO regulator (-55 μA).
• A dedicated 5 V step-down voltage regulator was added to power the RockBLOCK Iridium transceiver.
• Due to the sensor reaching its end-of-life (EOL), The LSM303 accelerometer/magnetometer was replaced with the LSM6DS33 + LIS3MDL IMU.
• Sensors are now powered directly through SAMD21 GPIO pins, allowing for power to be completely removed during sleep.
• A 2MΩ + 1 MΩ resistor divider is now used to measure the battery voltage (+2.4 μA).