CAPABLE, INEXPENSIVE, EASY: DEPLOYING FIELD ELECTRONICS

It's often useful to have a continuous record of environmental variables at a field site, these could include air or water temperature, wind speed, barometric pressure, stream flow, CO₂/other trace gas concentrations and even water and snow surface levels from satellite GNSS reflectometry. Discrete events can also be useful to record (lightning, triggered wildlife cameras, etc.).

Inexpensive, powerful microprocessors and sensors have become extremely available; the cost of computation has dropped to essentially zero. Software is now catching up; it is now easy to configure and program these sensors to serve as field instrumentation. The low cost not only removes barriers to researcher and student use, but allows multiple sensors to be deployed for dense spacial and temporal coverage not previously feasible.

A two-hour workshop in deployable field instrumentation is described. The training session uses a standardized Open Source development board based on an ARM processor (the Adafruit Feather M4) with standardized communication connectors (the Sparkfun Qwiic I²C system) to attached sensors. The Micropython interpreter is open source, free, and actively supported.

The development board can be programmed in the Arduino environment (a version of the C/C++ language), or using graphical programming (Blockly (Makecode)- or Scratch- derivatives). More interestingly, these boards can run a native Python 3 interpreter. The boards plug into a USB port and appear as USB flash drives, and Python scripts can be dragged and dropped in order to program the device. Development environments for debugging the Python hardware scripts are available, but only a text editor is actually necessary.

Using available code examples and device libraries, non-programmers can develop data logging sensor platforms, just by cutting and pasting Python code fragments. Additional variables can be measured by attaching a sub-board or plugging in a connector; no soldering is necessary. Weather resistance can be added by enclosing the board in food storage containers; solar cells extend the measurement lifetime.

After development cheaper solutions are available for actual field deployments, with the trade-off that they are not as easy to use. The workshop hardware totals less than $50, and this can be reduced by half per logging sensor node.