2 layers71.5 × 90 mm ATmegae Water Controller, the printed circuit board in 3D

ATmegae Water Controller

An open-source, standalone microcontroller PCB and embedded control system designed to automate water circulation, safety monitoring, and PID-controlled nutrient dosing for hydroponic tomato crops.

Open in PCBKit

Size: 71.5 × 90 mm
Copper layers: 2
Thickness: 1.6 mm
Parts: 23
Nets: 45
Pads: 125
Tracks, vias: 148, 0
Routed: Yes
KiCad: KiCad 10.0 (file 20260206)
Created: 17 Aug 2026
Updated: 17 Aug 2026

Overview

ATmegae Water Controller is an open-source printed circuit board by OmarAlsai, from the OmarAlsai/hydroponic-tomato-controller repository on GitHub. It is a 2-layer board of 71.5 × 90 mm with 23 parts on 45 nets, routed with 148 tracks and 0 vias.

It is built around the ATMEGA328P-PU, CH340C and LM2596S-12. Its parts include 7 capacitors, 7 connectors, 3 resistors, 3 ICs and 1 diode. It belongs with the AVR (ATmega, ATtiny) boards of this library.

Main components

README

README.md

ATmega328P Automated Hydroponic Tomato Controller

An open-source, standalone microcontroller PCB and embedded control system designed to automate water circulation, safety monitoring, and PID-controlled nutrient dosing for hydroponic tomato crops.

Key Features

Onboard ATmega328P MCU: Standalone design featuring dedicated power filtering, crystal oscillator, USB-C interface, and ICSP programming header.
Tomato-Optimized Dosing Engine: Pre-calibrated for heavy-feeding fruiting crops (Target EC: 2.2 mS/cm, Target pH: 6.0).
Discrete PID Control: Prevents nutrient overshoot by calculating precise dosing pump pulse durations based on concentration drift over time.
Hardware Safety Interlocks: Instant emergency pump shutdown triggered by low reservoir water levels to prevent motor dry-burning.
Noise-Filtered Analog Sensing: Software median-averaging filter to eliminate electrical noise on pH and EC sensor lines.

Hardware Architecture

Component	Function
ATmega328P-PU	Main 8-bit Microcontroller running at 16 MHz
CH340C	USB-to-Serial converter for simple USB-C flashing
Relay Driver Channel 1	Controls 12V Main Circulation Water Pump
Relay Driver Channel 2	Controls 12V Peristaltic Nutrient Dosing Pump
Analog Interface	Isolated signal routing for pH and EC/TDS probes

Pin Mapping

text

[ ATmega328P ]
  ├─ A0 ──────────► Analog pH Sensor Input
  ├─ A1 ──────────► Analog EC/TDS Sensor Input
  ├─ D2 (Digital) ─► Water Level Float Switch (Internal Pullup)
  ├─ D3 (Digital) ─► Main Circulation Pump Relay
  └─ D4 (Digital) ─► Nutrient Dosing Pump Relay

Parts

Qty	Value	Footprint	References
5	0.1 µF	Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm	C2, C3, C4, C5, C7
2	22 pF	Capacitor_THT:C_Disc_D5.0mm_W2.5mm_P5.00mm	C1, C6
2	5.1k	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R2, R3
2	Conn_01x03_Pin	Connector_PinHeader_2.54mm:PinHeader_1x03_P2.54mm_Vertical	J3, J4
1	10k	Resistor_THT:R_Axial_DIN0207_L6.3mm_D2.5mm_P7.62mm_Horizontal	R1
1	16MHz	Crystal:Crystal_HC49-U_Vertical	Y1
1	ATmega328P-P	Package_DIP:DIP-28_W7.62mm	U1
1	Barrel_Jack	Connector_BarrelJack:BarrelJack_Horizontal	J7
1	CH340C	Package_SO:SOIC-16_3.9x9.9mm_P1.27mm	U2
1	Conn_01x02_Pin	Connector_PinHeader_2.54mm:PinHeader_1x02_P2.54mm_Vertical	J5
1	Conn_01x04_Pin	Connector_PinHeader_2.54mm:PinHeader_1x04_P2.54mm_Vertical	J6
1	Conn_02x03_Odd_Even	Connector_PinHeader_2.54mm:PinHeader_1x06_P2.54mm_Vertical	J2
1	D_Schottky	Diode_THT:D_DO-41_SOD81_P10.16mm_Horizontal	D1
1	LM2596S-12	Package_TO_SOT_SMD:TO-263-5_TabPin3	U3
1	SW_Push	Button_Switch_THT:SW_PUSH_6mm	SW1
1	USB_C_Receptacle_USB2.0_16P	Connector_USB:USB_C_Receptacle_HRO_TYPE-C-31-M-12	J1

Questions

How big is the ATmegae Water Controller PCB?

It measures 71.5 × 90 mm and has 2 copper layers, 1.6 mm thick.

What parts does the ATmegae Water Controller use?

23 parts, built around the ATMEGA328P-PU, CH340C and LM2596S-12. The full list of its parts is on this page, with links to each part's symbol and footprint where PCBKit's library has them.

Where can I download the ATmegae Water Controller KiCad files?

From the OmarAlsai/hydroponic-tomato-controller repository on GitHub, at the commit this page was made from: the board is hardware/ATmegae_Water_Controller.kicad_pcb and its schematic hardware/ATmegae_Water_Controller.kicad_sch. PCBKit opens the board in the browser, with nothing to install.

Can I use the ATmegae Water Controller design in my own project?

Its repository states no licence, so its author keeps all rights: ask OmarAlsai before reusing the design.

Category and platform

AVR (ATmega, ATtiny)

Project files

Show this board on your page

A live frame, for any web page

<iframe src="https://pcbkit.io/embed/boards/omaralsai-hydroponic-tomato-controller" title="ATmegae Water Controller in PCBKit" width="100%" height="480" style="border:0;border-radius:12px" allow="fullscreen" loading="lazy"></iframe>

A picture

<img src="https://pcbkit.io/embed/boards/omaralsai-hydroponic-tomato-controller.jpg" alt="ATmegae Water Controller" width="1200" height="900">

A picture that opens the board, for a README

[![ATmegae Water Controller](https://pcbkit.io/embed/boards/omaralsai-hydroponic-tomato-controller.jpg?size=s)](https://pcbkit.io/boards/omaralsai-hydroponic-tomato-controller)

Source

Repository: OmarAlsai/hydroponic-tomato-controller
Board file: hardware/ATmegae_Water_Controller.kicad_pcb
Commit: a668f38
Licence: Not stated

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