PC Based Multiple Sensor control

Title: Temperature controlled by PC (personal computer)

What is the PC-Based?

Allow a devices such a sensor, microcontroller, LED, relay, stepper motor can be communicated and operate based on computer for further analysis and processing

Abstract:

An embedded system is an application that contains at least one programmable computer (typically in the form of a microcontroller, a microprocessor or digital signal processor chip) and which is used by individuals who are, in the main, unaware that the system is computer-based.

It is a PC based control technique where the device is controlled by a microcontroller (commonly 8051) with the aid of ADC converter. The PC system and the microcontroller system are linked with cables and ports that collectively control the temperature sensing and control.Lm35 temperature senses the temperature of the surrounding, gives its analog data to ADC converter, which further is fed to the 8051 microcontroller that is processed and fed to the PC by serial ports. PC synchronizes the data and gives graphs and accurate results. The cooling fan control that is on/off, speed-up and speed down are controlled by the 8051 microcontroller and all the results are displayed on the PC monitor. . The major difference in approach between any conventional method and the present one is the replacement of elaborate control circuitry of the former by an easily programmable algorithm with control equations in the latter. This gives one the flexibility in selecting and programming the control functions such as Set-point control and controlled heating / cooling through software. The salient features of the method include controlling any set point in 25 - 100_C in addition to an up-down variation in temperature with alterable rates and its ease of implementation, this method can be exploited in various modern day industries and day to day application. Basically PC based temperature control is widely used in process because:

•    Real time display of host computer, so that the user can monitor and view the measurement systematically and easily.

•    The measurement and control process display can be assigned by using various displays such as underlined, blinking, and change color in order to inform user for several information and warning.

    

• The graphical display can be show like real system with design a background of the system layout.

•    Add advanced features such as plot a graph for user information about the control process status.

Introduction:

LM35 is a temperature sensor that senses the surrounding temperature(range:-55 to 150 degree centigrade) and sends analog voltage output to the ADC controller for the analog data to be converted to digital data for the understanding of PC and 8051 microcontroller chip. The ADC converter converts the analog data to digital data which is fed into 8051 microcontroller. The microcontroller detects the data and decides whether to turn on the cooling system or not and passes on the information to the PC for display purpose through RS232. The PC simultaneously can be used to set the data parameters for 8051 microcontroller, processing etc.

PC based temperature control:

Design and develop a device to measure and control a temperature.Interface with a computer to display and control the temperature.Sense a room temperature and monitoring at computer.

_ Control a fan whether turn off or turn ON based a current temperature .

Scope of Work:

For this project, I was able to initialize the scope of work such as:

•    To study and research about PC-Based Temperature Control via internet, revision books and journal.

   To develop a project hardware design including:

·        Temperature Sensor.

·        ADC0804

·        Microcontroller P89V51RD2BN

·        Serial Interface(RS232)

•    To develop project software such as Visual Basic and Embedded c Programming.

 Project Design Procedure:

a)     Temperature Sensor – Used LM35 Temperature Sensor w hich the output voltage proportional to temperature in Celsius.

b)    ADC Chip – Convert the analog signal from sensor to digital signal for microcontroller processing and analysis.

c)     Microcontroller – Control ADC chip to measure a tem perature in physical form and analysis the data then transmit to computer for monitor and control.

d)    RS232 – Medium that been used in order to communica te between Microcontroller and Computer.

e)     Computer- Display and control the temperature.

f)      Visual Basic- A software to develop GUI for temperature display.

 g)     Fan – The fan will be turn On if current temperatur e more than set point temperature, otherwise the fan will be turn OFF.