Hotplate Wind and Rain Sensor
ABSTRACT
This document describes the experimental process of developing a non-mechanical hot plate wind and rain sensor. It aims to discuss practical aspects of the necessary hardware to fulfil such a function and different software approaches to controlling such a system. Specifically, it discusses an experiment based on 30W hot plates controlled by Labview in an attempt to measure changing wind and rain conditions. It also looks at the data gathered in this instance and calibration of the sensors. Finally it looks at ways of improving the functionality of such a system, through improved hardware design and better software control.
1 INTRODUCTION
The measurement of wind speeds and rain rates are important in terms of atmospheric monitoring and meteorological measurements. This project is to develop a combined wind-rain sensor using hot metal plates. For wind speed measurements, the moving air carries heat away from the hot plates at a rate dependent on wind speed. Providing power to maintain the hot-plate temperatures at their set point values can provide the quantification of wind speed. Similarly, raindrops landing on one of the hotplates will evaporate causing a further power drain on this plate. This project is to design, build and calibrate this sensor using Labview.
2 BACKGROUND
By keeping the two heated plates at a constant set point temperature it is possible to measure the power necessary to maintain this temperature. The change in power over time needed to maintain this state can be equated with wind removing heat from the plates. We can also evaporate water off one of the plates and measure the work done by the system in evaporation. The further energy required by this plate for water evaporation when measured will constitute a rain sensor. These plates will from now on be referred to as the rain plate or top plate and the wind plate or bottom plate.
If the bottom plate is kept dry while being exposed to the wind it can
This document describes the experimental process of developing a non-mechanical hot plate wind and rain sensor. It aims to discuss practical aspects of the necessary hardware to fulfil such a function and different software approaches to controlling such a system. Specifically, it discusses an experiment based on 30W hot plates controlled by Labview in an attempt to measure changing wind and rain conditions. It also looks at the data gathered in this instance and calibration of the sensors. Finally it looks at ways of improving the functionality of such a system, through improved hardware design and better software control.
1 INTRODUCTION
The measurement of wind speeds and rain rates are important in terms of atmospheric monitoring and meteorological measurements. This project is to develop a combined wind-rain sensor using hot metal plates. For wind speed measurements, the moving air carries heat away from the hot plates at a rate dependent on wind speed. Providing power to maintain the hot-plate temperatures at their set point values can provide the quantification of wind speed. Similarly, raindrops landing on one of the hotplates will evaporate causing a further power drain on this plate. This project is to design, build and calibrate this sensor using Labview.
2 BACKGROUND
By keeping the two heated plates at a constant set point temperature it is possible to measure the power necessary to maintain this temperature. The change in power over time needed to maintain this state can be equated with wind removing heat from the plates. We can also evaporate water off one of the plates and measure the work done by the system in evaporation. The further energy required by this plate for water evaporation when measured will constitute a rain sensor. These plates will from now on be referred to as the rain plate or top plate and the wind plate or bottom plate.
If the bottom plate is kept dry while being exposed to the wind it can
References: 1. Marsh, K N., Ed., Recommended Reference Materials for the Realization of Physicochemical Properties, Blackwell, Oxford, 1987. 2. http://www.world-aluminium.org/production/processing/properties.html 3. www.measurementcomputing.com/pdfs/usb-tc.pdf 4. http://www.national.com/pf/LM/LM395.html 5. Temperature-Electromotive Force Reference Functions and Tables for the Letter-Designated Thermocouple Types Based on the ITS-90. Natl. Inst. Stand. Technol. Monograph 175; 1993. 630 p.