Low-Cost Autonomous 3D-Printed Mini Disk Infiltrometer

Abstract

Hydraulic conductivity on the surface of the soil is crucial to address many hydrological and environmental issues. This study presents the development and validation of a low-cost Autonomous Mini Disk Infiltrometer (AMDI), fabricated using fused deposition modeling (FDM) 3D printing. AMDI integrates a transparent PET-G Mariotte chamber and a TDT-based TMS-4 sensor to allow automated measurement of cumulative infiltration under controlled pressure head levels. Calibration was performed using polynomial regression (cubic) to relate the readings of the TDT sensor to changes in water volume. Laboratory infiltration experiments on loamy Chernozem soil compared AMDI with a commercially available, manually operated minidisk infiltrometer (MDI) at pressure head levels of h0 = −6, −3 and −1 cm. The results of ANOVA did not show significant differences between AMDI and MDI in higher pressure heads (p greater than 0.05), with notable discrepancies at −1 cm (p less than 0.05) likely attributed to differences in the porous sintered stainless-steel disks, despite the hydraulic conductivity of the CTU disk being significantly higher than that of the soil. The influence of the porous disk was tested using MDI alone, which clearly demonstrated its effect on infiltration. This aspect should be further investigated to better define the impact of the disk on infiltration measurements. Moreover, despite the inherent porosity of FDM prints, air leakage was minimized through optimized printing parameters, allowing for reliable operation without post-processing or specialized equipment. The AMDI offers a functional, cost-effective (approximately € 218), and customizable alternative to traditional MDIs, with potential for broader adoption, including in citizen science applications. Further field testing is needed in diverse soil types and environmental conditions.