Open Field Logger Lab is a low-cost educational data logger from Leeman Geophysical for learning basic field data logging with 0-5 V analog sensors.
It is designed for students to assemble, test, and use during field measurement projects for our GEARS workshops and to then have a useful tool after the course. The goal is to teach practical instrumentation concepts without turning the logger itself into the main project.
This project is intended to help students learn:
- through-hole soldering
- sensor wiring
- analog voltage measurement
- calibration
- sampling rate tradeoffs
- SD card data logging
- basic field deployment practices
- the effect of real-world conditions on measurements
The logger is intentionally simple, low-cost, and easy to modify.
Open Field Logger Lab is not a precision commercial data logger. It is not intended for safety-critical measurements, unattended long-term monitoring, harsh environmental deployment, or calibrated scientific measurements without additional validation.
It is a teaching platform for learning how field logging works.
Rev A is built around:
- USB-C ESP32 DevKit-style microcontroller module
- ADS1115 16-bit ADC
- four nominal 0-5 V analog single ended inputs
- microSD card logging
- battery-backed real-time clock
- 9-18 VDC input power
- 5 V sensor power output
- simple status LEDs
- optional onboard NTC temperature divider
The analog inputs are intended for simple voltage-output sensors, signal conditioning circuits, and student-built measurement experiments.
Students solder only through-hole parts. Surface-mount parts are assembled before the workshop for time concerns. We do, however, have a surface mount soldering challenge for those that want to try SMT!
The through-hole assembly includes parts such as connectors, fuse clips, power components, sockets, and selected educational components.
Planned contents:
hardware/ KiCad design files, schematics, PCB layout, fabrication outputs, BOM
firmware/ ESP32 firmware for logging and self-test
docs/ Datasheets and other relevant files as well as assembly instructions
examples/ Example CSV files and simple analysis notebooks/scripts