Open Access data acquisition board with IoT support for aqua-culture applications

This files presents the design of an open access data acquisition board with Internet of Things (IoT) support for real-time water quality monitoring in aquaculture applications. The system was specifically developed for oyster aquaculture operations in the Sado River estuary, Portugal, where tanks are dis-tributed across remote riverbank locations spanning over several kilometers without reliable grid power or WiFi coverage. The hardware architecture employs a dual-microcontroller approach: a PIC18F46K22 microcontroller handles analog signal acquisition from six 4–20 mA current loop inputs and four 0–10 V voltage inputs, while an ESP32 microcontroller manages data processing, protocol conversion, and wireless transmission via LoRa, WiFi, and Bluetooth technologies. The board incorporates dedi-cated signal conditioning circuits with electrostatic discharge protection, overcurrent fuses, and noise filtering to ensure measurement integrity. Experimental validation against a calibrated HP 34401A multimeter demonstrated measurement errors below 0.3 % following software-based adjustment, with an expanded uncertainty of 8.2 mV for voltage measurements and 24 μA for current measurements. The complete hardware design, including schematics and printed circuit board layouts, is released under an open access license to enable community adoption and further development.