The Internet of Things (IoT) presents an opportunity to revolutionize agriculture through smart technologies that monitor environmental conditions and optimize resource use. However, one of the biggest challenges in deploying IoT devices in rural areas is ensuring energy autonomy, where access to power is limited and battery maintenance is often impractical. This paper proposes a low-cost, energy-autonomous IoT sensor node designed for smart agriculture in rural environments. We conducted a comprehensive review of energy harvesting technologies and integrated the most efficient solutions into our system, along with a microcontroller, sensors, and a robust communication protocol to transmit data reliably. In addition, a real-time web-based dashboard was developed, allowing farmers to monitor their crops from anywhere and make informed decisions to improve productivity and sustainability. The preliminary results are promising, demonstrating the viability of energy-autonomous IoT in enhancing rural agriculture while minimizing maintenance costs.