The Reef-Pi Pico is an aquarium controller board designed for a Raspberry Pi Zero or Raspberry Pi Zero W Linux single board computers. It offers a number of ports and built-in hardware to simplify building an aquarium controller using Reef-Pi

This is an open-hardware design, all design files can be found on Github.

Basic Specifications

• Power input: 12V, 2A, from a standard barrel jack power adapter. Internal power supplies for all other components

Input / output functions:

• Electrically isolated pH sensor (note: this sensor is not yet supported by released versions of the Reef-Pi code. Support is coming in Reef-Pi 3.0)
• 8 pin pluggable Phoenix COMBICON terminal block with poke-in wire connectors and removable plugs
• 2x 5V safe (internal pull-down) Schmitt-trigger inputs for float switches or other digital on/off sensors
• 2x 5V output (16mA) digital outputs
• 2x GND connectors
• 2x 5V connectors (500mA limit)
• 5V I2C (5V, SDA, SCL, GND) buffered output for longer wire lengths on 4 pin pluggable Phoenix COMBICON terminal block with poke-in wire connectors and removable plugs
• DB9: 8 open drain relay current sinks (1A, 12V clamped), 1 pin 12V power (from power adapter), for ADJ relay packs
• 2x 0-10V analog outputs on 3.5mm TRS (tip-ring-sleeve)/headphone connector using high quality Switchcraft connectors using Raspberry Pi PWM support
• Temperature using 1-wire sensors on TRS/headphone connector. ESD protected with with 3.3V supply
• Battery backed real time clock: Includes a battery backed real-time clock to allow for the Raspberry Pi to keep time even if there is no internet connection to synchronize from
• SMC: System management controller providing system reset and audible annunciator (beeper)

Configuring Raspbian

The following settings for the Raspberry Pi Zero should be used in [/boot/config.txt] (https://github.com/blueacro/reefpi-pico/blob/master/config.txt).

To fully utilize the Real-time clock, follow the instructions in this guide to remove the fake-hwclock package from Adafruit.