Introduction

SEMEA-TEC (Sowing Technological Solutions in Family Agriculture) is a university extension project at the Federal University of São Paulo (UNIFESP), São José dos Campos campus (ICT), approved by the Extension and Culture Board. The project operates at the intersection of computing, electronics, rural extension, and participatory methodologies, developing low-cost, low-energy-consumption social technologies for family agriculture, tackling the digital exclusion that deepens historical inequalities in rural areas.

The project is organically linked to an ongoing doctoral research at PPGIT/UNIFESP, entitled “Sociotechnical Co-creation with Family Farmers: Participatory Development of Technologies for Rural Areas,” which investigates the influence of participatory methodologies on technological innovation processes aimed at building autonomous communication systems in rural contexts. While the extension operates as a living laboratory for listening and co-creation with communities, the doctoral research investigates the technical-scientific foundations for achieving maximum energy autonomy — with batteries that harvest energy from the environment based on non-toxic, low-environmental-impact materials — and economic viability for scaling.

Methodology

We adopt Action Design Research (ADR) as our central methodology: before any line of code or soldering, we go to the field with partner organizations for active listening and participatory diagnosis of real needs. Only then do we move on to co-creating prototypes, testing on properties, and iterative cycles of continuous improvement. Family farmers are at the center of the process — not as passive beneficiaries, but as co-producers of technological innovation.

Our theoretical foundation is anchored in the Epistemologies of the South (Boaventura de Sousa Santos), Social Technology (Dagnino, Thomas), and the commitment to a just ecological transition, aligning our work with SDGs 1, 4, 7, 9, and 13.

Partnerships

The work is developed with undergraduate students from UNIFESP in collaboration with organizations working on the ground:

Associação Portal Sem Porteiras (Monteiro Lobato - SP) — logistical support, mobilization of family farmers, and sharing of local knowledge.
Akarui (São Luiz do Paraitinga - SP) — ecological and economic restoration integrating milk production with forest systems.
Associação Apoena — agroecology in the territory.

Prototype 1: JavAlarm — Electric Fence Monitoring via LoRa

The first development cycle emerged from observing an established practice in the territory: farmers use electric fences to protect crops and livestock against invaders, especially wild boars (Sus scrofa), an invasive species that causes significant damage to family agriculture in the Paraíba Valley. When the fence fails, the farmer often only discovers it hours or days later, when the damage has already been done.

JavAlarm is a low-cost, low-power system for detecting electric fence failures, combining simple hardware, optimized C/C++ firmware, and LoRa communication for operation in isolated rural areas. The architecture consists of two nodes:

Transmitter (TX): Connected to the electric fence, detects sudden voltage drops via an analog circuit using a Hall effect sensor and a dedicated fence voltmeter to capture high-voltage pulses (kV range). The microcontroller is a Raspberry Pi Pico W (RP2040) with a LoRa SX1262 transceiver at 915 MHz.
Receiver (RX): Receives the alert and notifies the user via LED, sound, or both.
A key differentiator is the acknowledgment (ACK) communication protocol: the transmitter sends the alert and waits for confirmation. If the receiver is offline, the transmitter retransmits until it obtains acknowledgment, ensuring that no fence failure goes unnoticed. Power consumption was optimized to 114 mA during transmission and 32 mA in idle, enabling weeks of autonomy on standard batteries.

Next steps: complete system integration, weatherproof case design, and bootloader optimization for remote firmware updates.

Prototype 2: Shitakiometer — Environmental Sensing for Mushroom Greenhouses

The second cycle addressed the needs of mushroom producers who must monitor temperature, relative humidity, and CO₂ concentration in production greenhouses. Shitakiometer is a high-energy-autonomy monitoring solution integrating sensors, LoRa communication, solar power, and a complete backend for real-time visualization.

Hardware: Heltec ESP32 with integrated LoRa radio (SX1262, 915 MHz), running custom firmware with deep sleep support. Sensors include DHT22 (temperature/humidity, ±0.5 °C accuracy) and MH-Z19B/SCD40 for CO₂ measurement via NDIR.

Power: 5V / 1.25W solar panel with 18650 lithium-ion battery (~2500 mAh) and charge management circuit, targeting continuous operation with positive energy balance — converging with the doctoral research on harvest energy.

Backend stack (fully containerized via Docker): Mosquitto (MQTT broker), Node-RED (automation bridge), InfluxDB (time-series database), and Grafana (real-time dashboards).

Ongoing work: deep sleep optimization for positive energy balance; farmer-friendly alerts via Telegram/WhatsApp; range and packet loss testing at the production site; weatherproofing evaluation.

Results and Expected Impact

To date, SEMEA-TEC has produced two functional prototypes with open documentation, manuals, and educational booklets. The expected impact includes training workshops for farmers and students, scientific articles, and a decentralized innovation ecosystem combining low-power radios, lightweight protocols, harvest energy, and participatory methodologies. Results will be shared on open-access platforms, at in-person meetings, extension fairs, and social technology forums.

Conclusion

SEMEA-TEC demonstrates that relevant technological solutions for family agriculture emerge when innovation starts from active listening and co-creation with communities. JavAlarm and Shitakiometer illustrate how LoRa communication, distributed sensing, and autonomous power can be combined into low-cost systems adapted to rural realities, with farmers as central agents. The articulation between university extension, doctoral research, and local partnerships points to a replicable model of technological social innovation in rural Brazil.

More information: https://semea.tec.br