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The Bioē project builds autonomous platforms that measure, record and transmit data from the sea on their own, designed for remote sites where servicing is expensive and infrequent. This page describes the technology behind them: hardware, firmware, radio links and mechanical design. The measurements these platforms collect in operation are presented under Experiments.
TS buoys — Wi-Fi data loggers
TS buoys — Wi-Fi data loggers
Built around an ESP32, each TS buoy carries a waterproof digital temperature probe and a hand-made electrode pair whose reading is logged as a raw value. The firmware wakes on an hourly cycle, averages 20 samples per sensor, posts a JSON record over Wi-Fi and returns to deep sleep. A Google Apps Script web app receives the record and writes it to a spreadsheet, where the calibration curve also lives — so a buoy can be recalibrated without being reflashed. Three units run independently, each with its own firmware and its own data sheet.
Long-range generation — LoRa network
Long-range generation — LoRa network
The current generation replaces the Wi-Fi link with LoRa. Each buoy is built on a Heltec WiFi LoRa 32 V2 — an ESP32 with an SX1276 radio — and sends short binary packets in the 915 MHz band to a base station on shore. The base acknowledges every packet, forwards it to the same spreadsheet backend, serves a live status panel on the local network and offers a Bluetooth console so a buoy can be checked in the field without opening its enclosure. Low-cost ESP32 sensor nodes installed near the base report over ESP-NOW instead of LoRa. A second, identical base station extends coverage and doubles as a backup: both stations hear the same buoys, and duplicate packets are discarded by sequence number. Sequence counters are kept in non-volatile memory, so a reset does not restart the numbering.
T1 — instrument buoy
T1 — instrument buoy
T1 is a LoRa buoy dedicated to continuous measurement. It carries a multi-channel, high-impedance front end — CMOS unity-gain followers feeding 16-bit analog-to-digital converters — for open-circuit potential logging of test surfaces, together with a waterproof temperature probe. A single protected 18650 cell sustains the hourly measure-and-transmit cycle for roughly one hundred days; a small solar panel with an MPPT charger is the next step.
Mechanics and field maintenance
Mechanics and field maintenance
The electronics live in a sealed enclosure above the waterline, with a cable gland at every penetration and one continuous, unbroken wire per sensor. A magnet and a reed switch let the buoy be woken and checked in the field without opening the box.
Oceanographic buoy
Oceanographic buoy
A large steel discus hull, 1.62 m in diameter, is being refurbished to carry project instrumentation. The work covers the hull and its mooring, registration with the Brazilian Navy, and the electronics. Once ready, the buoy will be moored in the São Sebastião Channel, next to CEBIMar-USP.
Code and documentation
Code and documentation
Firmware, backend scripts and hardware documentation are version-controlled in the project repository on UNICAMP's GitLab, with a public mirror on GitHub.
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