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Electrical Conductivity Sensing

Purpose

EC measures the ability of the nutrient solution to conduct electricity, which is proportional to the total dissolved salts (TDS) — the primary proxy for nutrient concentration. Low EC = under-nourished plants; high EC = salt stress.

Hardware

  • Sensor: TBD (e.g. Atlas Scientific EZO-EC)
  • Interface: TBD (I²C / UART)
  • Probe: conductivity probe, permanently submerged in sample reservoir

Integration

  • Polling interval: TBD (e.g. every 60 s)
  • Target range: depends on crop and growth stage — see Nutrient Solution
  • Temperature compensation: EC readings must be corrected for water temperature (configure EC sensor to use temperature input)
  • Correction: low EC triggers nutrient A + B dosing via Liquid Dispensing actor

Calibration

Two-point calibration required:

  1. Calibrate to dry air (0 µS/cm)
  2. Calibrate to a known standard solution (e.g. 1413 µS/cm or 12,880 µS/cm)

See Calibration for procedure.

Sources