A Low-Cost, Low-Power Water Velocity Sensor Utilizing Acoustic Doppler Measurement

Abstract

Current commercial sensors to monitor water flow velocities are expensive, bulky, and require significant effort to install. Low-cost sensors open the possibility of monitoring storm and waste water systems at a much greater spatial and temporal resolution without prohibitive costs and resource investment. To aid in this, this work developed a low-cost, low-power velocity sensor based on acoustic Doppler velocimetry. The sensor, costing less than 50 USD is open-source, open-hardware, compact, and easily interfaceable to a wide range of data-logging systems. A freely available sensor design at this price point does not currently exist, and its novelty is in enabling high-resolution real-time monitoring schemes. The design is capable of measuring water velocities up to 1200 mm/s. The sensor is characterised and then verified in an in-field long-term test. Finally, the data from this test are then used to evaluate the performance of the sensor in a real-world scenario. The analysis concludes that the sensor is capable of effectively measuring water velocity.

A Low-Cost Radar-Based IoT Sensor for Noncontact Measurements of Water Surface Velocity and Depth

“…For our sensor, while our error was 36% in field conditions and between 20% and 30% for the lab tests, this was over the entire range of the sensor. The low-cost, low-power in-water sensor proposed in [ 22 ] has RMS errors ranging from 17% to 43% between 200 mm/s and 1200 mm/s in long-term field testing. This performance is comparable with that of the radar sensor here.…”

“…Particularly, in-water sensors have been developed, such as the hydromast proposed in [ 21 ], which utilises the pressure exerted by the water flow to measure the water velocity at the bed of the channel. A low-cost acoustic Doppler sensor is proposed in [ 22 ] and uses continuous-wave ultrasonic Doppler to obtain a measurement for the water velocity.…”

“…While low-cost sensors have shown promise in accurately and inexpensively measuring water velocity, these in-water sensors need to be located within the water stream [ 21 , 22 ]. In-water sensors are susceptible to debris and may require hazardous confined-space entry to be mounted on the channel bed [ 23 ].…”

Low-cost monitoring systems for urban water management: Lessons from the field

“…First, a controlled laboratory experiment comparing the low-cost sensor's measurements to reference values will help qualify it and evaluate its performance, including range, accuracy, precision, reproducibility, and reliability ( Cherqui et al, 2020 ; Shi et al, 2021 ). Second, before and during field implementation, testing, calibration and periodic verifications of the system in real field environmental conditions will help characterize actual performance ( Catsamas et al, 2022 ; 2023; Shi et al, 2021 ). Field performance may differ from laboratory conditions due to environmental factors outside the range of those tested in the lab (e.g., temperature or humidity conditions, sunlight), a possibly different electrical setup (e.g., fluctuating power supply, rewiring to accommodate field conditions), and, importantly, a possible drift over time that might not have been detected in short-term laboratory testing.…”

Calibración de canales aforadores en sistemas irrigados mediante el procesamiento de imágenes de video y la inferencia bayesiana

“…Existe una amplia gama de instrumentos hidrométricos que pueden utilizarse para calibrar un canal aforador. Muchos de ellos son de alto costo, inaccesibles para establecimientos de pequeño y mediano porte (11) . De forma más simple y económica, el desplazamiento de partículas o trazadores es un método no intrusivo que permite calcular la velocidad mediante la observación directa de la trayectoria de las partículas en el agua (12) .…”