尋熱變頻風扇系統之設計與製作

Abstract

本專題主要使用微控制器，AT89S52，類比數位轉換器，ADC0804、以及熱敏電阻，CONN FLEX2來感測溫度並分析，首先利用熱敏電阻隨著溫度高低改變自身內部的電阻值，並將電阻值的類比資料利用ADC0804轉成數位資料輸出，來達到感測溫度的效果。接著透過程式來判斷兩端溫度差距，如果兩端的溫感分別感測到的溫度沒有相差太大，表示現在溫度左右兩邊溫度差不多且沒有熱源正在加熱，若溫度相差有點大代表某一邊的熱敏電阻有感受到熱源。我們需要找出熱源的方向並且判斷溫度的高低，利用3種燈號的閃爍(紅/黃/綠)各代表不同溫度範圍將目前熱源的溫度範圍高低顯示出來。當判斷完成後，馬達與風扇便會啟動，往一方溫度較高者轉動，若是同一邊的熱敏電阻阻值瞬間相差很大的話，代表熱源加溫非常的快，風扇起動之後，會在熱源附近停留幾秒，達到即時降溫的效果。另外，若是溫度範圍較高，風扇的轉速就會增強，並且持續偵測熱源，若是熱源遠離或是溫度降低，風扇的轉速便會下降，達到一種變頻的效果，有效的達到感測溫度並且降溫的效果。

This is primarily used AT89S52, ADC0804, CONN FLEX2 (thermistor) to detect the temperature change. The internal resistance of the thermistor varies as the temperature changes. The variation of the internal resistance is convected to the digital signal by using the ADC convecter and then fed to the microcontroller . Then through the program to determine the temperature difference at both ends. If the ends of the temperature sense were the sensed temperature is not much difference, that the temperature on both sides of the temperature almost without heat source is heating. If the temperature is a little big difference represents one side of the thermistor has to feel heat, we need to find the direction of the heat source and determines the temperature level. The use of three kinds of lights flashing (red / yellow / green ) each representing different temperature ranges . The current range of high and low temperature heat source is displayed. When it is judged complete, the motor and the fan will start turning toward the higher temperature side, if the same side of the thermistor resistance moment. Then a big difference on behalf of the heat source heating is very fast, the fan starts after a few seconds will be staying near a heat source, to achieve immediate cooling effect. In addition, if the temperature is high, the fan speed will be enhanced and sustained detect heat. If the heat source or away from the temperature decreases, the fan speed will be reduced, to achieve a frequency effect. Effectively achieve the sensed temperature and the cooling effect.