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From Hydra-Reef

• Getting Started
• Hardware
  • Assembling a Hydra
  • Info for hardware developers
  • Options for Relay control
• Software
  • Info for software developers
  • PH Calibration
  • Available firmwares
• User Projects
• Ethernet fixes for rev 0.3 boards
• Setting up ThingSpeak for charts

Contents 1 Hydra: A controller for reef aquaria. 2 Included Functionality 3 Project Status 4 Discussion 5 Getting Files

Hydra: A controller for reef aquaria.

The Hydra project is an effort to create a framework for building an Arduino-compatible controller for reef aquaria. This project is aimed at people who are interested in hobby electronics but may not know where to start when applying them to monitoring and controlling a reef aquarium.

The Hydra project is focused on creating an Arduino-compatible hardware design and firmware to run it. In addition, the project will provide guidelines for developing additional hardware and software to achieve functionality beyond that included in the base project. Through this means, the project team hopes to create an environment where aquarium hobbyists can have a library of additional hardware and software compatible with the core Hydra controller.

Hardware development strives to follow these guidelines:

• Incorporate functionality desirable for controlling and monitoring a typical home reef aquarium.
• Keep the design "simple" enough that a novice electronics hobbyist would be comfortable with assembly
• Maintain shield compatibility with official Arduino hardware.

Software development strives to follow these guidelines:

• Incorporate code to operate the hardware included in the Hydra mainboard.

Included Functionality

The current design of the Hydra includes hardware to support the following functions:

• Monitoring pH through a stable amplifier circuit.
• Driving an LCD to provide a visual indication of tank conditions.
• Timekeeping via an onboard RTC.
• Additional I/O, memory, and processing power via a second AVR acting as an I2C slave (Hence the "Hydra" name, implying multiple heads).
• Ethernet connectivity, allowing for remote control and/or notification of alarm conditions.

Simple I/O functionality - sensing float switches, reading temperatures, etc. - is implemented via GPIO pins and/or 1-Wire or I2C slave devices separate from the main PCB. In addition, a relay module will be developed separately from the main PCB to control 120v AC devices.

Project Status

The project is currently in a development stage. We have recently released the second beta revision of the hardware and are currently developing the firmware to run it. For more information on the firmware go to Available firmwares.

Discussion

For discussions, please visit the Hydra thread on Reef Central

Getting Files

The design files (schematic, pcb, BOM, and gerbers) can be found on the Google Code Page. To download the actual files, follow that link, click on the file you're interested in (on the right side of the screen) then click the "view raw file" link near the bottom-right corner of the screen.

Hydra was designed using Cadsoft EAGLE. The pcb and schematic files can be viewed in EAGLE. A freeware version of EAGLE can be downloaded from the Cadsoft website.

The BOM (Bill of materials) is an excel spreadsheet - any software that can view excel files can be used to open it.

The Firmware page lists current firmware for the board.