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!!!

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.

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.

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.

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. 

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~~

  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.