A low-cost portable chamber based on Arduino micro-controller for measuring cover crops water use

•A low cost (~210 $), small (28L) portable closed chamber was built based on an IoT approach.•Indoor and outdoor calibration vs. gravimetry showed linear models with R2 > 0.96.•Optimal measurement time window was set at 60 s after time zero (i.e. 15 s after chamber positioning).•Diurnal rates measured in pots with either tilled or grassed surface agreed with literature.