Output Circuit

 1. LCD

LCD pins diagram

The most commonly used LCDs found in the market today are 1 Line, 2 Line or 4 Line LCDs which have only 1 controller and support at most of 80 characters. Most LCDs with 1 controller has 14 pins. Pin description is shown in the table below:

Character LCD pins with 1 controller

Display data RAM (DDRAM) stores display data represented in 8-bit character codes. Its extended capacity is 80 X 8 bits, or 80 characters. The area in display data RAM (DDRAM) that is not used for display can be used as general data RAM. So whatever user sends on the DDRAM is actually displayed on the LCD. For LCDs like 1x16, only 16 characters are visible, so whatever user write after 16 chars is written in DDRAM but is not visible to the user.

LED circuit connection

Above is the connection diagram of LCD in 4-bit mode, only 7 pins needed to interface with an LCD. D4 - D7 are the data pins connection and Enable and Register select are for LCD control pins. The Read/Write (RW) pin of the LCD will not be using, as the data only writing on the LCD. So, it has to be grounded permanently. If user wants to use it, then they may connect it on controller but that will only increase another pin and does not make any big difference. The unwanted data pins of LCD i.e. Vss, VEE and D0-D3 are connected to ground.

There are many reasons why use LCD in 4-bit mode instead of 8-bit. One basic reason is lesser number of pins are needed to interface LCD.

2. LED

LED Output Circuit

When OUTPUT 2 receive logic condition from the microcontroller, R10 (330kohm) will limit the current to the D3 LED. The D3 LED will on.

3. Relay Switching

Relay Switching Circuit

For the above circuit, when the base of the transistor receive any supply from the microcontroller, it will allow the 5V to the ground without active the relay. Otherwise, the relay will active and create a back e.m.f that will turn the switching from the normally open to normally close (which is turn on the Backup RCCB).

Component

I was bought the component  that i need in my project. It not all the component but the main part of this project i was bought it.

Circuit and PCB Design

I have finish to design the my schematic and PCB layout for my project Air quality monitoring system by using the EAGLE (Easily Applicable Graphical Layout Editor).

 I was try to run this schematic and it complete running and functioning (Alhamdulillah)

 schematic design

This is the PCB layout that i will print in on the board and all component will be solder on it (insyaAllah)

PCB layout

Meeting with supervisor

 August 9
I was attend first meeting with my supervisor  Tn Hj.Dr. Zainuddin bin Kornain for this semester. Show him my progress report and his give some advise and give me the idea in complate my project.

this sem i am stating to make the hardware, not just the proposal and report.............it getting hard....

The Taguchi Gas Sensor

After doing some research and some advise from Tn Hj.Dr. Zainuddin i finally choose the Taguchi gas sensor (TGS2600) to apply in this project, , TGS2600 will be chose as a gas detector due to the small size, high sensitivity and lower price compared to other gas sensor. This sensor is widely used in many sensor and detector applications.

• Why i choose TGS 2600?

1. This sensor is widely used in many applications such as in robotic machinery, smart extinguisher, aromatherapy sensing and many more. The characteristic of this sensor has been compared with the newly developed sensor for benchmarking purposes. This shows that the TGS2600 is a very reliable sensor for detecting air contaminant level in the environment.
2. The TGS 2600 has high sensitivity to low concentrations of gaseous air contaminants such as hydrogen and carbon monoxide which exist in cigarette smoke. The sensor can detect hydrogen at a level of several ppm. Figaro also offers a microprocessor (FIC02667) which contains special software for handling the sensor's signal for appliance control applications

Meeting with Supervisor

In this weeks meeting with Tn Hj.Dr. Zainuddin,  we went through the project plan i created the week previous. The project plan included the features of sensor which I wanted to include in the project and ideas about each and how i would design it. In our last discussion i agree with Sir Zainuddin idea to apply the Taguchi gas sensor in my project due to it is the good sensor

Estimating the Budget

This week i not have many class due to the public holiday. so, my friend and i went to the Jalan Pasar to survey the price of the component, estimating the exact budget for my incoming final year project and to complete the proposal report that i need to submit to my supervisor . From my surveillance,the price is reasonable and still put on my budget. Alhamdulillah, my plan will going smoothly insyaALLAH.