~The End of Project~ (17/10/2010)

Author: Our Diaries // Category:
For the last day, we had a simple rehearsal for our presentation. Hope that everything will be fine and the circuit can work during our presentation.


Last but not least, THANK YOU for reading!!!
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~Preparation for the Presentation~ (16/10/2010)

Author: Our Diaries // Category:
Today we discuss about what and how we gonna present our project on 21st October 2010. 


Basically, we have to present our project in 10 minutes. During the presentation, we will point out the objectives, how we test the circuit, the function of all components, the results and discussions, conclusions and so on.
 After that, we have to show the output of circuit.
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~Report Day~(15/10/2010)

Author: Our Diaries // Category:

1.        According to the project requirement, our report need to be be short and concise (8 pages max) that include the following:
a.       Group name, group leader and member name list.
b.      Objective/problem statement
c.       Function of the important component and the circuit itself (please include references if it is referred  from  somewhere;  website/ books etc)
d.      Methodology
e.      Result and discussion
f.        Application of the circuit
g.       Conclusion & Future work
h.      References 

In the report, we wrote down all the experiences that we gained, how we test the circuit, the results and the discussions. Besides, we also discuss about the application of the dark/ light activated switch in our daily life.
For example, the dark activated switch is applied in the street light and the light activated switch is applied in the security system.




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~Going in Lab IV~ (14/10/2010)

Author: Our Diaries // Category:
Today, our group members, Han Leong and Redzuan retest their circuit.





Obviously, the speaker at the left hand side one have louder sound. Their project have done practically.




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~Going in Lab III~ (13/10/2010)

Author: Our Diaries // Category:
After successfully tested the circuit by construct the circuit in the breadboard, we soldered all the components in the copper board. During the soldering process, we learn tat the components especially the transistors(BC547 and BC557)  should not be soldered over a certain period of time as the transistors can be easily damaged if overheated.

After finished soldering, we test the circuit again.

Our circuit that are soldered in a copper board




 It is found that the Green LED does not glow again!!!

However, after recheck the circuit, we found that one of the pin ( that connect to input) is not well soldered. 

 

As shown in the video, 
In the dark activated switch, the relay(Green LED) is switched on when the LDR is covered from the light exposure.
In the light activated switch, the relay(Green LED) is switched on when the LDR is exposed to light.
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~Going in Lab II~ (12/10/2010)

Author: Our Diaries // Category:
It is our turn to test the circuit. 

 After connect the positive terminal to a power source of 12V and the negative terminal to ground, we turn on the switch.......

ERmmmm......The result is ..... 

      Red LED turns on but Green LED does not turn on.
It meant relay does not work!

Sigh....we have to troubleshoot the circuit.  At first, we thought that it is the relay problem. However, we realized that we had made a mistake in the construction of circuit. The relay is not connected and thus cannot be switched on. We finally successfully troubleshooted our circuit and the relay can be switched on already.
 

The following is some simple and general analysis about our circuit :

When we switched to A ( assumption), the relay is switched on when the LDR is in light condition; when we switched to B(assumption), the relay is switched on when the LDR is in dark condition.

 The next step is to solder all the components in a copper board. Let's fight for our project~~
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~Going in Lab~ (11/10/2010)

Author: Our Diaries // Category:
  Today we observe our group members, Han Leong and Redzuan to construct their circuit.

Description about their circuit : 
The circuit of Group 15
            A 555 squarewave oscillator is used to produce a 1 kHz tone from an 8 ohm speaker. In the circuit on the left, the speaker is isolated from the oscillator by the NPN medium power transistor which also provides more current than can be obtained directly from the 555. Thus, the sound will be louder. In the circuit on the right, the speaker is directly driven from the 555 timer output. Thus, the sound of the speaker will less louder than the left circuit.


Smartly, the circuit successfully work on the first try. As what we expected,   The speaker in the left hand side is louder than the right hand side.  


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~Simulation II~ (10/10/2010)

Author: Our Diaries // Category:
After experienced the failure of simulation yesterday, we decided to reconstruct the circuit. The BC547 is replaced by BC547B because BC547 is not available in the software.


FINALLY, THE CIRCUIT CAN WORK!







Thus, we record all the voltages at each nodes with different resistance of LDR and potentiometer.
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~Simulation using circuit maker~ (09/10/2010)

Author: Our Diaries // Category:
Before construct the circuit in a breadboard, we decided to simulate the circuit first using software to get the  result. For this part (Simulation), Soo Ling will be the leader.

Firstly, we construct the circuit as shown in the project : 


For the relay, we connect the normally close pin to the LED to show the output.
After testing..........

DISAPPOINTINGLY,

            WE FAILED TO SIMULATE THE CIRCUIT DUE TO SOME ERRORS IN THE FILE!!!


It seem like we have to work harder....
                              
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~ Function of all the components~ (08/10/2010)

Author: Our Diaries // Category:
 It is very important for us to understand the function of all the components before we construct the circuit to prevent any accidents. Thus, today Fazlina (as our leader) had assigned us to find the function of components.
The following are the function of important components:


a)   Relay - Acts as a switch when certain amount of potential difference is applied across the solenoid so that the switch is change state to allow potential difference across certain load connected.

b)   Transistor BC547 (Q1 and Q2) - form a Schmidt trigger

c)   Transistor BC557 (Q3) - Actual switching of relay

d)   Transistor BC557 (Q4) -  Inverting switch of relay

e)   IN4004 diode - Allows an electric current to flow in one direction, but blocks it in the opposite direction

f)   SPDT switch - Connects the relay to the collector of either transistors


g)   LDR and potentiometer - Form a voltage divider which is used to apply bias to a transistor 

h)   LED - Show the output by emitting light when an electric current passes through it


The websites that we have visited today are:
  • http://www.kpsec.freeuk.com/components/relay.htm
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~Our Schedule~ (07/10/2010)

Author: Our Diaries // Category:
The following is the schedule for our project:

Day 1 - Day 3:
  • Start a blog
  • Understand the  project given
  • Make a introduction about the project
  • State out the problem statement and objectives
  • Make a schedule
Day 4:
  • Study of all the components needed in our project
  • Understand the function of components
  • Find source and data sheet from internet
  • Collect components 
Day 5:
  • Simulate  the circuit by using circuit maker
  • Understand the part that occurs error in simulation
  • Troubleshooting
  • Simulate the circuit so that we can understand how the circuit work.
  • Record all the observations.
Day 6 - Day 7:
  • Find source and data sheet from internet
  • Construct the circuit in a breadboard.
  • Testing
  • Troubleshooting
    Day 8 - Day 11:
    • Testing the circuit in a breadboard practically in the lab.
    • Record all the observations and results.
    •  Troubleshooting
    • Observe the other group members in doing their project.
    • Record all the observations and results.
    • Comments on their performances.
    • Solder the circuit in a copper.

    Day 12 - Day 14:
    •  Start the preparation for report
    •  Discuss the outcome of project
    •  Print out



    .
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    ~Kit 79C---> LDR Light/Dark Activated Relay Switch~ (06/10/2010)

    Author: Our Diaries // Category:

    Some briefing and purposes about our project~~
    Problem Statement:
                In our daily life, we usually meet with the problem where we want to switch on or off certain electronic devices for a certain time period when the light intensity is changes, such as the outside lighting on driveways, security system, counters, night lamp and so on. We need some devices that will control the electronic devices smartly by varying the light intensity, thus a LDR light or dark activated relay switch which required a light-dependent source (LDR) as the input of the circuit that will varies certain parameters in the circuit.

    Main Objectives :
    To build a LDR light or dark activated relay switch circuit that can be implemented in real world applications.

    Sub-objectives :
    i)                    To learn how the values of the potentiometer can change the sensitivity of the Light Dependent Resistor (LDR).
    ii)                  To learn the function of each components in the circuit design in varying the result of the output of the circuit.
    iii)                To learn how to ease the circuit building by using circuit simulation software.
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    ~ Preparations~ (05/10/2010)

    Author: Our Diaries // Category:
    Today we took our components that are needed from lab assistant. Unfortunately, some components such as BC547, BC557 and so on are not provided by faculty and we have to buy those components in order to complete our task. In the evening, we went to Jalan Pasar to buy those components and equipments. We decided to buy all the components because its can be used as a backup components for our project if the components provided have broken. We have to postponed our experiment to Friday as tomorrow we have to attend to a talk about Aerospace at DECTAR.
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    ~Introduction to Our Project~ (04/10/2010)

    Author: Our Diaries // Category:
    This blog named "Our Diaries", which meant the whole diaries about our introduction of project, procedures, simulation of circuit, problems that we meet, discussions and so on. Our (group 16) project title is DIY Kit 79C, which is a LDR Light/Dark Activated Relay Switch.



     The components needed to build the circuit are:
    a) Resistors of different resistances
    b) Rheostat
    c) BC547 and BC557
    d) Diode
    e) LED
    f) Relay
     g) LDR
    h) SPDT Switch
    After having a discussion, we decided to analyze the task given first before start or conduct the circuit. Besides, we also planned to buy the components that were needed for our project in case of any unwanted accidents occurs during the experiment.
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