The displaced air does go farther up after the car passes. If it were lower, or farther towards the back of the vehicle, it could have problems. That is well above the displaced air, and skin friction height. People test anemometers with cars all the time. You are a better engineer than me for being able to keep up with all of that stuff. My simple mind tends to avoid RTOSs and use scheduler stacks. What is purpose of the light sensor? Radiated solar power? Flux vs wavelength?ĬMSIS is a significant abstraction layer. RH is seldom > 50% for more than a few hours, and can be in the single digits for several days during Santa Ana wind events. Resultant wind-speed vector accuracy is 1% when ambient is 60mph winds each summer/fall during ‘Santa Ana’ winds. ![]() For these I use hot-wire anemometers in tubes, where the vector math is similar to the UA system (which is where I got the idea of using air flow ‘vectors’). I cannot access top of the mast on two of my weather stations. Someone want to run this in spice for a bode plot? The UA signal conditioning circuit response does not make sense (am probably wrong because I just did two single-point calculations). ![]() As each unit seems to be a custom tweak, my failure was probably related to the many details involved in the construction and calibration and configuration of such an instrument. Rock on dude.Īttempted to make an UA about 8 years ago (same reference design that this guy used) and was never successful as the two cited examples. Posted in Tech Hacks Tagged anemometer, ultrasonic sensor, weather station, wind sensor Post navigationĪny engineer with the brilliant foresight of using SCons is good to go for me. IF you prefer simplicity, the more common cup anemometers can be built from a range of scrap materials, including old hard drive parts and plastic Easter eggs. ![]() We covered another ultrasonic anemometer a few years ago, but it had a different sensor arrangement. All the hardware and software are open-source and available on GitHub. The fact that none of the sensors have moving parts is a major advantage for this use case, and we look forward to seeing the boat project. plans to use the QingStation on an autonomous boat, so he also included an IMU, compass, GPS, and a microphone for environmental sounds. Other sensors include an optical rain sensor, light sensor, lighting sensor, and a BME280 for air pressure, humidity, and temperature. This might due to a calculation error, or external factors like wind, or disturbed airflow from the test car or other traffic. This yielded readings that were proportional to the car’s GPS speed, but a bit higher. ![]() Since does not have access to a wind tunnel for testing and calibration, he improvised by mounting the anemometer on his car’s roof and going for a drive. The design and experimentation process is well-documented. For an ultrasonic anemometer to work properly, it requires a carefully designed analog amplifier on the receive side and a lot of signal processing to extract the correct signal from all the noise caused by secondary echoes, multi-pathing, and the environment. Wind direction can be calculated by taking velocity readings from two ultrasonic sensor pairs perpendicular to each other and using a bit of simple trigonometry. They work by measuring the time it takes for an ultrasonic audio pulse to be reflected the receiver across a known distance. Ultrasonic anemometers have no moving parts but come at the cost of significantly more electronic complexity. For ’s QingStation, he decided to build another type of wind sensor: An ultrasonic anemometer. Weather stations are a popular project for experimenting with various environmental sensors, and for wind speed and direction the choice is usually a simple cup anemometer and wind vane.
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