Ultrasonic liquid level sensor

grabcad

The Arduino Mega 2560-based device incorporates an HC-SR04 ultrasonic sensor and a 3.2 TFT LCD display, making it easy to measure water levels. With a tranquil tank, the device sends out an ultrasonic pulse that reflects off the water surface with a 99.99% density of the original wave to an ultrasound receiver. The reading is calculated using the reflection coefficient R = (Z2 - Z1) / (Z2 + Z1), where Z1 represents air's acoustic impedance at 417 Pa*s/m, and Z2, water's acoustic impedance at 150 * 10^4 Pa*s/m. To protect against splashing water, a modified ultrasonic sensor is used with a rubber cover plate, increasing the acoustic impedance to 600 Pa*s/m. Upon reflection from the water, the wave's density remains almost unchanged. With simplified calculations, the reflected wave's power is assumed to be 82% of the original wave, losing 18% upon passing through the rubber cover a second time. The receiver is configured to receive 67.24% of the original wave's power, enabling accurate measurements displayed on the device in percentages up to 100%. Designed for tanks up to 1.5 meters high, the device can also display readings in volume or weight units if needed. Additionally, it calculates the combined percentage of filling from six tanks, providing comprehensive monitoring capabilities.