DIY Planted Aquarium CO2 Reactor with Color Sensor Feedback
Build an automated planted aquarium CO2 injection system with Zigbee solenoid control, Raspberry Pi scheduling, and TCS34725 color sensor feedback using Krill's node-based IoT platform.
Krill
Decentralized process control & automation, built for makers.
Run a krill server on a Raspberry Pi, a laptop, or a rack box. Open the app on any device on your network. Wire sensors, schedulers, calculations, GPIO and dashboards into a live swarm — no cloud, no accounts, no rented brain. The architecture pros use for SCADA, scaled down to fit on a workbench.
your network live · mDNS · LAN
krill server · home.local
phone
control
desktop
dashboard
esp32
sensors
relay-pi
actuators
tablet
journal
laptop
editor
server broadcasts · apps subscribe
zero config · no port forwarding
decentralized
Local-first, by design
Servers discover each other on your LAN and pair into a swarm. Your data, your hardware, your network — never anyone else's cloud.
process control
Real automation, not toys
Data points, cron timers, calculations, GPIO, alerts, dashboards — composable nodes wired into directed graphs. Inspired by industrial SCADA.
maker-first
Runs on a Pi
Aquaponics, vivariums, breweries, greenhouses, workshops. Drop a server on a Pi, plug in sensors, build the system you actually wanted.
pro-grade
Architecture pros use
Typed nodes, explicit observer model, deterministic graph evaluation. The same patterns that run factories — without the seat-license bill.
New to krill? Start with the walkthrough.
Four minutes. Three nodes. One mental model that scales from a single thermostat to a building's worth of sensors.
Pinned Posts
Check out the Categories Menu for a wealth of examples, experiments, blogs and more info.SMTP Email Alerts
Send email alerts from any Krill trigger with the SMTP executor — wire it to thresholds, cron timers, or logic gates to notify recipients via your own SMTP relay.
Project Dashboard: Live Data, Video, and Automation at a Glance
The Project Dashboard brings live sensor data, camera feeds, diagrams, graphs, and automation controls into a single organized view.
Raspberry Pi Camera - Live Monitoring and Event Snapshots
Live camera feeds from Raspberry Pi Camera Module 3 in the Krill app
Pi4J gRPC Service for Raspberry Pi
A gRPC serivice that provides access to Pi4J features on Raspberry Pi hardware, allowing you to control GPIO pins and sensors from a Java 21+ application without needing Java 25.
LLM Integration — Wired, Not Chatted
Run a local LLM with Ollama in your home automation — summarize sensor data, write alerts, and act on the results offline on your own hardware.
Moving Water with Relays and Solenoids
A simple example of using relays and solenoids with water sensors to automate keeping my aquarium topped off with water.
Using Sensors with CircuitPython
Read I2C and GPIO sensors on a Raspberry Pi with CircuitPython for home automation and data logging.
Zigbee and MQTT Integration
Controlling Zigbee devices over MQTT
Turn A Raspberry Pi Into A Kiosk With Custom SVG Dashboards
Install Krill Server in Kiosk Mode for Touchscreens