PROJECT DESCRIPTION DESIGN FEATURES. HARDWARE and SOFTWARE Used

Transcription

1 1 PROJECT DESCRIPTIO Development of a microcontroller based feedback control system for automatic operation control of basic electrical appliance for an industry, commercial or residential building. The system controls the appliances based on the desired room condition, outside condition, number of people in the room and available power. DESIG FEATURES Our design includes the following features: a. Automatic Temperature Control b. Light Control c. Function according to available Voltage Level d. Occupancy Sensing e. Fire/ Over Heat Alarm HARDWARE and SOFTWARE Used 1.Software used : Software Purpose 1 MikroC Pro for AVR Microcontroller code 2 Extreme Burner AVR Code burning 3 ISIS 7 Professional Simulation 4 ARES 7 professional PCB Layout 2. Hardware used: Component ame Specifications 1 MicroController AtMega32L 5V supply, 40Pins 2 Oscillator Crystal External -8MHz 3 Temperature Sensor DS18B20-55 o C-128 o C 4 Transformer Center Tapped Xf 220V-12V/24V 5 Motor Driver IC L293D - Motor DC Gear Motor 12V 6 LDR - 100Ω-2MΩ 7 LED 5V LED Red,Green,White 8 Potentiometer - 470KΩ,100KΩ,33KΩ,10KΩ 9 FA DC Fan 12V 10 MOSFET IRF LCD 2Line Display - 12 Resistors, Capacitors - Various Values

2 2 DESIG APPROACH Flow Diagram : POWER O Prople In? Ti<50 o C %Power <40% R=X1 Close Heater On Close Window Open? Window Open? To<32 o C 32 o C<To<34 o C ALARM %Power 40%<P<70% %Power >70% R=X2 R =X3 Open Window Open? 34 o C<To<38 o C Light Out Enough? Light On? Open Window Open? 38 o C<To<48 o C Turn On Light Illumination = R Turn Off Light Fan1 On P>5 Fan2 On F2? F2 Off Close Window Open? To>48 o C AC On

3 3 DESIG PROCEDURE : 1. Function, Placement and Connection of Components : TEMPERATURE SESOR () : Two temperature sensors are used to sense outside and inside temperature and turn temperature controlling appliances on and off according to need. Placement : One sensor inside the room and one Outside the room Function : T being the outside temperature microcontroller makes decision on which appliances to turn on to best satisfy the desired room condition based on the following logic table. Logic Heater Window Fan AC ALARM T<32 o C On Off Off Off Off 32 o C T<34 o C Off Off Off Off Off 34 o C< T<38 o C Off On Off Off Off 38 o C< T<48 o C Off On On Off Off 48 o C T<50 o C Off Off Off On Off Tin>50 o C Off Off Off Off On LIGHT SESOR : The light sensor is made our of LDR, MOSFET, Potentiometer and Laser. Placement : Placed outside the room. Function : The function of this sensor is to help the system detect whether there is sufficient natural light and turn the room light on and off accordingly if people are inside. OCCUPAC SESOR: Also made our of LDR.MOSFET Potentiometer and Laser. Placement : Two sensors are places on the entrance and exit doors of the room Function : Check for the number of people in the room and control number of fan and lights to turn on. o of People in the Room o of Fans Turned On o of Lights Turned On >5 2 1 WIDOW SESOR This sensor is also made out of LDR, MOSFET, Potentiometer and Laser. Placement : It is placed on the side of the window Function : Checks to see whether the window in the room is open or closed, so that the system doesn t try to open the window while it is already open or when there is no-one in the room and the window is left open, the system closes it automatically.

4 4 TRASFORMER A transformer is used in our system to detect the available power level. We used a center tapped transformer which steps the main power supply down to 12Vac which is rectified by a rectifier circuit to make it into a suitable micro-controller input voltage. Placement : It can be placed near the main power supply. Function : The transformer helps the system keep track of available power and hence help maximize utilization of available power under low voltage conditions. MOTOR( DC GEAR MOTOR) We have used a 12v DC gear Motor in our system. A Gear motor has been used in place of a regular DC motor due to the fact that it can hold its state after its turned off. Placement: The motor is placed near the window. Function : The motor helps Open and Close the Window. MOTOR DRIVER IC (L293D) A motor driver IC is used in the system to drive the high power devices. Here we have used L293D motor driver IC which has 4 inputs and 4 output terminals. Placement: The IC is placed on the PCB circuit. Function : The IC delivers enough current to drive the DC Gear Motor and also the two Fans in the system. Two of the outputs are dedicated to the motor and the other two to the two fans. It has H-bridge connections inside it which enables us to drive the motor in both directions. 2LIE LCD DISPLA A 2Line LCD Display is used in the system to show the condition of the room. Placement: The IC is placed on the PCB circuit. Function : The LCD Displays the following data : LIE Line 1 Line 2 DISPLA Inside Temperature Ti Outside Temperature To o Of People Inside(1 Char-When enters/leaves) % Power Appliance Condition 2. Microcontroller Programming and Simulation The microcontroller was programmed to follow the logic functions mentioned above and perform according to the flow diagram shown at the beginning. Before making physical Implementation we tested in in Proteus to see if the system was able to carry out the desired functions.

5 5 3. PCB Circuit of Control System Our Circuit has been designed centered around the Mcrocontroller. Our aim was to use the available microcontroller pins in the most efficient way possible. The following chart shows the function of each port of the microcontroller in our system : PORT SERVES AS PI ame PI o Connected To PA0/ADC0 40 ADC (Power Level Detection) PA1/ADC1 39 Temperature(OUT) Sensor PORT A All Input PA2/ADC2 38 Temperature(I) Sensor PA3/ADC3 37 Light Sensor PA4/ADC4 36 Window Sensor PB0 1 Motor Driver(In1-2)-For Motor PB1 2 Motor Driver(In2-7)-For Motor PB3 4 AC PORT B All Output PB4 5 Heater PB5 6 Motor Driver(In3-2)-For Fan1 PB6 7 Motor Driver(In4-7)-For Fan2 PB7 8 Fire Alert PORT C LCD Connections PC3 PC Line LCD Display PORT D Occupancy Check PD2/IT0 16 Person In By Interrupt (IT) PD2/IT1 17 Person Out

6 6 The other connections made to the AtMega32L are : Component Pin ame Pin o Purpose Crystal Oscillator XTAL1 13 External Crystal Oscillator 8MHZ XTAL2 12 5V Supply RESET 9 Keep Reset Button High VCC 10 uc Power Supply Ground/0V GD 11 uc Ground We simulated the circuit with the above mentioned connections in ISIS 7 Professional and drew out the PCB layout using ARES 7 Professional. Then printed it out and soldered the different components on to it to get the final circuit. DESIG COSIDERATIOS 1. LASER SESOR : Although IR sensor pairs are easily available in the market we decided to make our own laser based system using LDR, MOSFET, Potentiometer and Laser Light. This was done mainly due to the problems we faced with IR sensors. The IR sensor s transmitter is not unidirectional, it has low sensitivity which lead to bad response, while our laser response worked very well giving an almost perfect 0V and 5V margin.

7 7 LDR POT MOSFET IRF640 POT LDR Door and Window Sensor Light Sensor 2. DC GEAR MOTOR : Instead of normal DC motor we have used DC Gear motor.ormal DC motor cannot hold it s state and its shaft can be manually turned which is not desirable. But on the otherhand DC gear moto can hold its state after its been turned off, it cannot be manually turned and it has higher torque. 3. TRASFORMER : We have used a transformer in our system for supply power level detection. But in reality an office is usually run by a battery IPS system which is unaffected by slight voltage level alterations in the main power supply. Our purpose was to make sure maximum utilization of available power occurs this condition arises in load shedding conditions where maximum usage of battery saved power needs to be made by the office. But as we could not incorporate a battery IPS system in our practical design we have used a transformer, a rectifier circuit and potentiometers to show effect of low voltage supply. Full-Bridge Rectifier Transformer AC POT1 POT2 + 5V for 12V (dc) ADC - 220V-12V (ac) 4. PWM(Pulse Width Modulation): It is not a required part of the actual system but in our testing system we used PWM to demonstrate that we could sense the input supply voltage and act accordingly(displayed through light intensity change). In practice, the actual system could send out control signal which would help the system switch between various voltage regulating circuits like high performance voltage circuit, economic voltage circuit etc.

8 8 SSTEM SETUP For the system to be up and running the following steps must be followed: a. Sensors must be put in place b. Proper connections must be made to the available appliances c. Connection to transformer must be made to check power supply d. motor connections must be made properly with a 12V supply d. The Specification must be entered in code SSTEM COST The price list of the main parts of the actual system is as follows: Component Price (Tk) Microcontroller AtMega32L 600/= Temperature Sensor DS18B20 (2X150/=) 300/= PCB Print +Design 250/= LCD 2Line LCD Display 180/= MOSFET IRF 640 (4x30/=) 120/= LASER (3X30/=) 90/= Motor Driver IC (L293D) 80/= Potentiometer (1X4/= + 3X4/= + 2X5/=) 30/= LDR 4x4/= 16/= Capacitor (22p, 2.2m) = 2x3/= + 10/= 16/= Crystal Oscillator 8MHz 8/= Others Diode,Resistors,Rail,Base etc 100/= So the total price of the system would be : Tk.1790/= The extra things we needed for the testing : Component Price(Tk.) Motor DC Gear Motor 400/= Fan (20/=+40/=) 60/= Transformer Center-tapped 220V-12V 140/= Building the Room Wood,Screw,Glue,Tape,etc 600/= The total cost of the extra components is : Tk.1200/= So, the total cost of our project is : Tk.2990/=

9 9 SSTEM OPERATIO TEST As it was not possible for us to implement the control system in an actual office room we made a test room ourselves (as shown in the picture). The whole Energy Smart Office Control System Test Design The program was made such that normal room temperature would serve as colder temperature when the heater would turn on and temperature was increased by a holding a soldering iron near the sensor. The occupancy check was done by placing our hands in front of the sensors to indicate people going in and out.

10 10 ADVATAGE OF ECO-FRIEDL SMART OFFICE ROOM COTROL SSTEM Automation Temperature Control : The main advantage lies in the fact that it is an automated system which will handle all your appliances according to desired condition specified in system. Power Saving :It has means of working under low voltage conditions and maximizes utilization on available energy at load-shedding situations. Eco-Friendly : It is eco-friendly in the aspect that when the condition outside is pleasant and matches with the specifications provided, it turns off the high power appliances and lets nature help in obtaining desired condition. Versatile : The versatility of the system lies in the fact that each appliance is functioned based on a logic, so it could be altered to serve any facility required just by altering the logic table. o Human Required : It can be programmed to control machine rooms, server rooms, clean rooms etc where human presence is not desired yet a certain condition is needed to be maintained. Fire Detection : It has a Fire alarm which alerts incase of a fire. In System Programming : The circuit has in system programming facility, so the operation could be changed according to season just by loading the new program in by the programmer. Low cost and Simple : It is a low cost system, costs only about Tk.1800/= so it is affordable and also very simple to implement. Appropriate for BUET : This system could be easily implemented in BUET. Often the teachers and students leave without turning off the lights and fans. This system could alter those mistakes easily. And often the temperatures in the labs are either too cold or hot which needs to be monitored by the lab assistants. This system could take care of this matter easily.

11 11 Possible Additions to the System Complete Fire Protection System : By integrate an appropriate sprinkler system the system could also provide fire protection. Security System : As the system checks for the number of people that goes in and out a security system could also be incorporated in the system for high-security facilities. Presence Sensing Illumination : Along long corridors or big rooms presence sensing illumination can be provided for by using pressure sensors. Common Digital Clock : We could integrate a real time clock just by using an IC (DS1307) in the system and thus provide a common digital clock for the entire office. Salary Calculation : By integrating an card punch system with the occupancy sensing the staff attendance and working hours could be logged and salary calculated accordingly. Decision Making : In boiler system, our system could be use to make instant decisions on what to do based on the temperature needed. Temperature Log : the temperature sensing portion could be used for keeping a temperature log but saving data in EPROM. REFERECES Data Sheets of Various IC s : ACKOWLEDGEMET We would like to thank our lab teachers Dr. Md. Ziaur Rahman Khan and Sajid Muhaimin Choudhury for allowing us to take on this project. We were able to construct the project based on our logic, intuition and knowledge of electronic circuits without the help of any previously done projects.