AquaControl32-4R is an intelligent ESP32 T-Relay controller for my 80 L tetra aquarium. It is implemented in Arduino and PlatformIO. It monitors water temperature with a DS18B20 sensor, runs a thermostat, and schedules lights and CO2 on/off events.
The system sends data to ThingSpeak. View here: ThingSpeak dashboard for channel 2421172
The goal is to preserve the health of the aquarium and its fish — black tetras, which thrive in tropical temperatures.
| Signal | GPIO | ThingSpeak Field |
|---|---|---|
| DS18B20 sensor | 22 | 1 |
| Heater relay (K1) | 21 | 3 |
| LED bar relay (K2) | 19 | 5 |
| CO2 solenoid relay (K4) | 5 | 6 |
| On-board status LED | 25 | — |
| Endpoint | Method | Auth | Description |
|---|---|---|---|
/health |
GET | none | Liveness check; returns status, datetime, water temperature and relay states. |
/lamp/toggle |
GET | HTTP Basic | Toggles the LED bar relay. |
/co2/toggle |
GET | HTTP Basic | Toggles the CO2 solenoid relay. |
This DIY build is housed in a Shako HT200 plastic box (90x140x180mm) and uses a 4x4 socket panel, ESP32 T-Relay, waterproof DS18B20 sensors, a 12V supply, wires and wago connectors.
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- Remote log via telnet
- Persist thermostat parameters in config
- Generate OpenAPI spec for the REST API
- Add more metrics to the health check endpoint
- Bug: lamp turned on after cron
- Log file
- Save mqttPubTopic
- Refactor
main.cpp: extractinit*()functions into a separate module (initWifi, initOta, initHttpServer, initCron) - Wifi reconnecting