Cabai (Capsicum annuum L.) merupakan komoditas hortikultura bernilai ekonomi tinggi yang memerlukan pengelolaan irigasi untuk mendukung pertumbuhan tanaman secara optimal. Penyiraman manual yang tidak terukur berisiko menimbulkan over watering maupun under watering yang berdampak negatif pada pertumbuhan tanaman. Penelitian ini bertujuan merancang dan mengimplementasikan prototipe sistem irigasi tetes tanaman cabai berbasis IoT yang mengintegrasikan metode ETc Hargreaves–Samani dan Fuzzy Logic Mamdani untuk menghasilkan keputusan penyiraman adaptif. Sistem menggunakan ESP8266, sensor suhu DS18B20 dengan koreksi data Open-Meteo, capacitive soil moisture sensor, relay, pompa DC, Firebase, dan aplikasi Android. Data suhu digunakan untuk menghitung ETc, sedangkan nilai ETc dan kelembapan tanah menjadi input fuzzy untuk menentukan durasi penyiraman. Pengujian black box dan white box menunjukkan fitur dan jalur logika program berjalan sesuai spesifikasi. Pengujian selama 10 hari menghasilkan durasi irigasi 9–19 detik per sesi dengan volume air 19,98–42,18 ml. Total volume air pada ETc + Fuzzy sebesar 331 ml, sedangkan ETc murni sebesar 369 ml. Hasil tersebut menunjukkan bahwa sistem mampu menyesuaikan keputusan dan durasi penyiraman berdasarkan kebutuhan air tanaman dan kondisi aktual kelembapan tanah.

Chili pepper (Capsicum annuum L.) is a horticultural commodity with high economic value that requires proper irrigation management to support optimal plant growth. Unmeasured manual watering may lead to overwatering or underwatering, which can negatively affect plant development. This study aims to design and implement an IoT-based drip irrigation prototype for chili pepper plants by integrating the Hargreaves–Samani ETc method and Mamdani Fuzzy Logic to generate adaptive irrigation decisions. The system was developed using an ESP8266 microcontroller, a DS18B20 temperature sensor with Open-Meteo data correction, a capacitive soil moisture sensor, a relay, a DC pump, Firebase, and an Android application. Temperature data were used to calculate ETc, while ETc values and soil moisture served as fuzzy inputs to determine irrigation duration. Black-box and white-box testing showed that the system features and program logic paths functioned according to the specified requirements. A 10-day test produced irrigation durations of 9–19 seconds per session, with water volumes ranging from 19.98 to 42.18 ml per session. The total water volume applied using the ETc + Fuzzy method was 331 ml, compared with 369 ml using the ETc-only method. These results indicate that the system is able to adjust irrigation decisions and durations based on crop water requirements and actual soil moisture conditions.