Nft hydroponic controller

NFT Hydroponic Controller — Open-Hardware PCB

Status: v1.1 boards fabricated and assembled by JLCPCB. Bring-up and on-site testing in progress.

A 4-layer, ESP32-S3 based controller board that turns a manual NFT (Nutrient Film Technique) hydroponic system into a self-regulating one. It reads pH, EC and water level from the main reservoir, switches up to six 12 V pumps (nutrient A, nutrient B, pH adjust, circulation, …) and integrates natively with Home Assistant through ESPHome.

The goal: replace the breadboards, loose jumper wires and relay modules that most DIY hydroponic builds end up with, with one board you can order pre-assembled from JLCPCB, screw your sensors and pumps into, and flash.

Why this exists

NFT systems work by running a thin film of nutrient solution under the plant roots. The hard part is not the plumbing, it is keeping the solution chemistry right: pH drifts, EC drops as plants feed, and the tank level falls. Doing that by hand every day is what makes most home systems fail.

This board closes that loop:

 pH / EC / level sensors ──► ESP32-S3 ──► Home Assistant (automations decide dose)
          ▲                                      │
          └──── main tank ◄── dosing pumps ◄── relays ◄─┘

The ESP reports readings, Home Assistant decides how much A/B nutrient or pH-down to dose based on calibrated set-points, and the board drives the pumps.

Features

Repository layout

.
├── nft-hydroponic-controller.kicad_pro   KiCad project (open this)
├── nft-hydroponic-controller.kicad_sch   Schematic
├── nft-hydroponic-controller.kicad_pcb   PCB layout
├── nft-hydroponic-controller.kicad_dru   Custom design rules
├── nft-hydroponic-controller.csv         Bill of materials with LCSC part numbers
├── nft-hydroponic-controller.xml         Netlist
├── DRC.rpt, ERC.rpt                      Design rule / electrical rule check reports
├── libs/lcsc/                Symbols, footprints and 3D models imported from LCSC
├── Custom_JLCPCB_Parts/      Custom parts library
├── compunents/               Additional vendor symbols/footprints
├── fp-lib-table, sym-lib-table   Project-relative library tables
├── firmware/esphome/         ESPHome config + secrets template
└── docs/images/              Photos and renders

All library paths are project-relative, so the project opens without missing symbols or footprints on a fresh machine.

Requirements

• KiCad 10 or newer (the files are saved in KiCad 10 format and will not open in older versions)
• Optional: the Fabrication Toolkit plugin (KiCad Plugin & Content Manager) to export JLCPCB-ready Gerbers, BOM and pick-and-place in one click — settings are included in fabrication-toolkit-options.json

Ordering the board

1. Open nft-hydroponic-controller.kicad_pro in KiCad.
2. Open the PCB editor and run Fabrication Toolkit (or export Gerbers, drill files, BOM and CPL manually).
3. Upload the generated ZIP to JLCPCB. Select 4 layers, 1.6 mm.
4. Enable PCB Assembly and upload the BOM and CPL. The LCSC part numbers are already assigned.
5. Through-hole parts (relays, screw terminals, barrel jack, large electrolytic) can be assembled by JLCPCB or hand-soldered.

Ready-made manufacturing files are also attached to each Release.

Using the relay channels

Each channel's terminal block is Volt IN / Leg 1 / Leg 2-GND.

• Internal 12 V (default): leave the channel's switch in the internal position. The pump connects between Leg 1 and Leg 2-GND and runs from the board's 12 V input.
• External voltage: wire your supply into that channel's Volt IN terminal and flip the channel's switch to external. Use this for pumps or loads that need something other than 12 V.

Pin mapping

ADS1115 (I²C address 0x48): pH → AIN0, EC → AIN3.

Firmware

The board runs ESPHome and reports to Home Assistant over MQTT (with MQTT discovery, so entities appear automatically). The config is in firmware/esphome/nutrient-controller.yaml.

This is the configuration used during development. Check the pin assignments against the pin mapping above before flashing it to the v1.1 board.

Setup:

1. Copy firmware/esphome/secrets.yaml.example to secrets.yaml and fill in your Wi-Fi, MQTT broker and passwords.
2. Plug the board into your computer via USB-C (no need to press BOOT, auto-reset is on board).
3. In Home Assistant → ESPHome Builder, create a device, paste the config, and choose Install → Plug into this computer.
4. After the first flash, updates happen over Wi-Fi.

Calibration

pH and EC probes drift and vary between units, so set-points must be calibrated per probe:

• pH: two-point calibration with pH 4.0 and pH 7.0 buffer solutions.
• EC: calibrate with a known reference solution (e.g. 1413 µS/cm).
• Dosing: dose a small, measured volume, wait for the tank to mix, and record the change in pH/EC. This gives the "dose per unit change" used by the automations.

Safety

• The relays are rated for mains voltage, but this board is designed for 12 V DC loads only. Do not switch mains through it unless you understand creepage/clearance requirements and have an enclosure rated for it.
• Water and electronics: mount the board above the reservoir, in an enclosure, with drip loops on every cable.
• Keep the pH-down acid and nutrient concentrates away from the electronics.

Project status

Contributing

Issues and pull requests are welcome, especially: tested pin mappings for other sensor probes, enclosure designs, and Home Assistant automation improvements. If you build one, open an issue with a photo.

Credits

Designed by Hasan Abuzaid — Mechatronics Engineering, German Jordanian University. Developed during an IoT/embedded internship at Nexus Nature.

License

Hardware: CERN-OHL-S-2.0. Firmware and configuration files: MIT.