單晶微電腦在化學感測教學上之應用

本論文旨在開發化學感測教學實驗，而這些實驗中是以利用含8951單晶微電腦、ADC、OPA、LCD之微電腦界面及各種感測元件等，以偵測酒精濃度、河川濁度、空氣溫濕度、雨水導電度及CO2濃度等。各種感測元件感應到不同的環境變化時，即呈現出不同的電壓值，這些類比訊號的電壓值，經由ADC轉換成數位訊號，並由8951單晶片處理後，顯示於LCD上，或是傳送到電腦，成為資料收集的基礎。在酒精濃度偵測的實驗中，是利用SnO2半導體感測元件及8951微電腦界面，並針對市面上各種解酒液對酒精分解的功效，及人們飲酒後，所能被偵測出的酒精含量為研究主題。在河川濁度偵測的實驗中，是以台灣中部三條主要河川：大甲溪、大肚溪及濁水溪為研究範圍，以CdS感光晶片及8951微電腦界面來測河水的混濁程度，進一步分析三大河水的濁度變化。在溫度及濕度偵測的實驗中，分別利用溫度計及濕度感測器和8951微電腦界面來偵測溫度及濕度，是偵測每天早、中、晚空氣溫度及濕度的變化，並記錄一年內的溫度及濕度變化。在雨水導電度的實驗中，是利用三根電極及8951微電腦界面來測量雨水的導電度。並以台中縣市為研究範圍，將收集到的雨水，測其導電性做分析比較。在CO2濃度偵測的實驗中，是針對學生在體育課中做完各項不同的運動後，所吐出的二氧化碳與澄清的石灰水反應成混濁的碳酸鈣，再經CdS的偵測，來反映CO2含量的多寡。雖然8951只是一顆8位元的單晶片，但它已具備了微電腦硬體結構的五個主要單元，能夠達成簡單的輸入、輸出、運算、控制及記憶功能，所以可成為教學上的良好輔助工具。

關鍵字

89C51 ； ADC0804 ；酒精偵測；濁度偵測；濕度偵測；雨水導電度

並列摘要

Some teaching experiments on chemical detections were developed. Various detection systems with 8951 microcomputer interfaces including one-chip microcomputer 8951, ADC (Analog to digital converter), OPA (operational amplifier), LCD (Liquid crystal Display) and various sensors were prepared and applied to detect alcohols, turbidities of rivers, temperature, humidity of the air, electricity of rain and CO2 in the air respectively. Various sensors used in this study exhibited, quite sensitive to the environmental variations and showed the change in voltage output, which was converted into digital signal with ADC. The digital signal was transport to a microcomputer or a LCD display device. In the detection of alcohols, a SnO2 semiconductor sensor with the 8951 microcomputer interface was employed to detect the alcohol contents after drinking various wines and commercial alcohol-relievers to study the alcoholic catabolism of the people. In the detection of turbidities of rivers, a CdS photo-sensitive crystal with the 8951 microcomputer interface was applied as a quite sensitive sensor to detect the turbidities of main rivers in Taiwan, e.g., Tachia River, Tatu River, and Choshui River. In the measurements of temperature/humidity, a thermal couple detector and a water-sensitive polymer detector with the 8951 microcomputer interface were applied to detect the changes of temperature and humidity within a year and the variations in one day from morning to night. In electricity of rain measurements, use there Electric wires with the 8951 microcomputer interface was employed to detect the electricity of rains in each area in Taichung. In the detection of CO2, the CdS photo-sensitive detection system was also used to detect the CO2 content in student’s breath after physical exercise. Although one-chip microcomputer 8951 is just an 8-bit microcomputer, it has equipped the five main units and can be used for signal output and input, signal calculation, control and memory of the signal. The one-chip microcomputer 8951 has successfully applied as an excellent tool in the experimental Teaching.