Measurement of wind speed using an anemometer is very important in various fields. The most effective and efficient type of anemometer is the ultrasonic anemometer. This research develops an Arduino-based ultrasonic anemometer using the HC-SR04 sensor with a Kalman filter to reduce noise and integrated IoT with the Blynk application on a smartphone. The advantage of ultrasonic anemometer is not having analog signal conditioning and analog filters, thereby reducing the possibility of having noise, low cost, and can be monitored remotely. The ultrasonic anemometer has been calibrated on the wind tunnel and has a measurement resolution of 0.10 m/s and a measurement error of 0.14 m/s.