Ultrasonic Sensor-Based Weight Measurement Using Extension Spring

In this letter, we proposed an ultrasonic sensor based weight measurement method suitable for measuring weight in small quantities. In the method, an ultrasonic sensor is mounted on top of the vertically suspended extension spring, whereas, at the bottom of it, a circular metal reflective plate is attached. With increase in weight in a pan attached to bottom of the spring, the separation distance between ultrasonic sensor and reflective plate is increased linearly. The ultrasonic sensor in association with data logger is programmed to measure the separation distance. The proposed method has advantages of having no hysteresis effect, highly repeatable in nature, linear in responses, and simpler in design.