R&D · Open Hardware
Digital Water Parameter Monitor
An open-source, low-cost water quality monitoring device designed to integrate directly with this platform. Continuous, automated parameter logging — pH, temperature, dissolved oxygen, EC, and more — sent directly to your Water Monitor without manual testing.
The Problem
Chemical test kits are time-consuming
Manual testing with liquid reagents or test strips is accurate but takes 15–30 minutes per session and relies on human consistency and colour perception.
Trends are invisible between tests
Weekly testing misses rapid pH crashes, oxygen dips overnight, or temperature spikes. Problems often discovered too late when fish or plants are already stressed.
Commercial monitors cost £300–£2000+
Professional aquaculture monitoring systems are prohibitively expensive for hobby and small-scale operators. There is no open, affordable alternative.
Sensor Suite
pH Probe
Available Now£8–£25Analog glass electrode, BNC connector · Range: 0–14 pH, ±0.01 accuracy
Requires calibration with pH 4.0 and 7.0 buffer solutions. Atlas Scientific offers lab-grade options.
Temperature (DS18B20)
Available Now£2–£6Digital 1-Wire sensor, waterproof · Range: -55°C to +125°C, ±0.5°C
Extremely reliable, widely used. Waterproof probe version essential for submersion.
Dissolved Oxygen
Available Now£35–£120Galvanic or optical probe · Range: 0–20 mg/L, ±0.1 accuracy
Optical probes are more accurate and require less maintenance than galvanic. Atlas Scientific DO circuit recommended.
EC / TDS Sensor
Available Now£5–£40Conductivity probe for dissolved solids · Range: 0–5000 µS/cm
Useful for tracking overall mineral load. Correlates with GH and nutrient availability.
KH / Alkalinity
In DevelopmentSoftware-calculated or £60+Titration-based or calculated from CO₂ + pH · Range: 0–500 ppm CaCO₃
Automated KH measurement is expensive. Can be approximated from pH + CO₂ readings. Manual test kits most practical currently.
Ammonia / Nitrate
Coming Soon£80–£250Ion-selective electrode (ISE) · Range: 0–100 ppm
ISE probes exist but are expensive and less reliable. Currently recommended to combine with digital logging of manual test kit readings.
Core Hardware Components
ESP32 Microcontroller
£4–£8Main processor + WiFi/Bluetooth
Low power, dual-core, WiFi built-in. Handles multiple sensor inputs and sends data to the app via HTTP or MQTT.
Atlas Scientific EZO Circuits
£35–£70 eachpH, DO, EC signal conditioning
Professional-grade sensor interface boards. Far more reliable than raw probe circuits. Open source library available.
LiPo Battery + Solar
£10–£25Off-grid power option
3.7V LiPo with TP4056 charging circuit + small solar panel enables fully off-grid operation for remote tanks or greenhouses.
Waterproof Project Box (IP67)
£6–£15Enclosure
Essential for greenhouse or outdoor deployment. All electronics housed in sealed box with cable glands for probes.
OLED Display (optional)
£3–£7Local readout
128x64 I2C OLED shows current readings locally without needing phone/app. Useful for quick checks.
App Integration Architecture
✓ What will work at launch
- Configurable reading intervals (e.g. every 15 minutes)
- Automatic population of Water Monitor log entries
- pH trend tracking with nitrification runway predictions
- Temperature alerts via email notification
- All historical data visualised in the app
⟳ On the Roadmap
- Compatibility Engine auto-update from live sensor data
- Community anonymised parameter heatmap by region
- Predictive pH crash alerts (ML-based trend detection)
- Multiple devices per user account
- Offline mode with sync on reconnect
Development Roadmap
DIY Build Guide
Open-source schematics, PCB layouts, and firmware published on GitHub. Community members build their own at sub-£75 total cost.
Calibration & App Sync
Firmware connects to Open Aquaponics API. Sensor readings automatically posted to your Water Monitor log on a configurable interval.
Kit Assembly
Pre-assembled PCB kits with tested sensor circuits available via the Shop — no soldering required. Target price sub-£120.
Fully Assembled Unit
Tested, calibrated, plug-and-play device. Simply place probes in tank, connect to WiFi, and readings flow into the app automatically.
Open Source & Community-Built
All hardware schematics, PCB layouts, and ESP32 firmware will be published under an open-source licence. Electronics engineers, makers, and aquaponics practitioners are invited to contribute, adapt, and improve the design. The goal is a robust, affordable, community-maintained device that any grower worldwide can build, buy, or improve. Hardware files and firmware will be hosted on GitHub and linked from this page when available.