LuumScope: a portable, low-cost brightfield microscope for in-field soil observation

Soil is a complex ecosystem on which we are heavily dependent for food production, water regulation, and nutrient cycling. Its biodiversity should be periodically monitored, as it is a key indicator of soil health. However, smallholder farmers and field technicians rarely have the tools to observe soil organisms directly. A major reason is that conventional microscopes are costly, fragile, and generally unsuited to field work. Here we present the LuumScope, a portable, low-cost, open-source brightfield microscope designed specifically for in-field observation of soil mesofauna. The instrument uses interchangeable M12 CCTV lenses, a rechargeable LED illumination system, and a 3D-printed body with a screw-driven focusing stage. Samples can be placed directly in a small Petri dish, requiring no flattening or slide preparation. The LuumScope was validated through participatory workshops with agricultural technicians and smallholder farmers from the FAO Global Soil Doctors Programme in Mexico. Participants with no prior microscopy experience operated the device within minutes and successfully observed mites, springtails, fungal structures, and other soil organisms. Beyond soil observation, preliminary tests demonstrate potential applications in health sciences, plant pathology, and ecological research. Here you will find the files to print or modify all 3D-printed parts for replicating the LuumScope: - base - top - stage - stage_lid - focusing_knob - leg (x3) - leveler (x2) - lens_frame_min - lens_frame_max