Temperature Measurment

Annop Suksan
Yu Sun

Project Description:

In our project, Raspberry pi is used to read temperature data via SPI communication from ADC (AD7705), which converts analogue temperature sensor(LM35) output to digital level. Data are displayed as plot with Qt real-time plotting and the data must be recorded into SD card. Code can be written in C.


Experiment introduction:

Metal sport bottle is commonly used in our lives, but there exists a drawback that when it is full of boiled water or coffee, it is untouchable since its metal surface, and sometimes even burns people. In this project we are going to measure the hot coffee, from 100C until it cools down to 45C, and try to hold the bottle every 5C decrement and record the moment and temperature at which the bottle can be held for 10s, that means it is the temperature people can accepted. (Sometimes people can hold for a second and find it is still hot!).

In the experiment, a thermometer will be inserted inside the bottle to measure the liquid temperature and temperature sensor LM35 is attached outside the bottle at the metal surface, timer is also used. When inside temperature is lower than 45C. Since we get two channels of temperature sensors so we use the Channel 2 to measure the room temperature, because it is also a factor which affects the water temperature.

Temperature Sensor (LM35) => Analog to Digital Converter (AD7705) => Raspberry Pi => Display using Qt real-time chart.


Experiment Result and Conclusion:

The picture here just shows how temperature change when a sensor is held by hand and the other is burned in the fire maker.

Experiment picture can be seen here.

As the result, the maximum temperature human being can suffer from is 54C and this result can hopefully to be applied to the human being safety ensuring design.

Time

Liquid temperature(C)

Surface temperature (C)

If can be hold

0

96

96

No

1:20

95

95

No

7:57

90

90

No

11:04

85

85

No

16:15

80

80

No

21:15

75

80

No

27:38

70

70

No

32:49

65

65

No

36:05

60

59

No

37:35

57.5

54

Yes

58:47

45

42

Yes


Detailed project report,and code are attached. video is here

http://www.youtube.com/watch?v=dHzu8wta_3A&feature=youtu.be

For Video discription, just see the comments in the video.