Week 12 - April 28th Last project lab session today .....

Finally the pressure is off as everything come to an end.  I am overwhelmed because I finish everything which I was required to hand up. Meaning I done the complete board with everything working properly and thus, achieving my aims. I spent all the holiday doing the report and some other assignments in other modules, in the lab I completed the whole report then handle up the printed PDF files. The final part was to submit the same PDF report on the moodle; which I did and finally handing up the complete hardware at the very end. Overall, everything went as smooth as I wanted it to be despite the lack of not using the Humidity sensor (which is a Surface Mount Technology) in this project. 

The finished product.

Homemade 15-pin D-sub Cable:

Temperature Algorithm:

Pseudo code for LCD mode switch menu:

/**Welcome Message **/
Case 0: 
Lcd.setCursor(0,0); 
Lcd.print(“Kings- B ”); 
Lcd.setCursor(0,1); Lcd.print(“00092297”); 
Break;

/**Temperature Reading **/
Case 1: 
Lcd.setCursor(0,0); 
Lcd.print(“Temp: ”); 
Lcd.setCursor(0,1); 
Lcd.print(“ oC”); 
Break;

/**Humidity Reading **/
Case 2:
 Lcd.setCursor(0,0); 
Lcd.print(“Humi: ”); 
Lcd.setCursor(0,1); 
Lcd.print(“ %”); 
Break;

/**Light Reading **/
Case 3: 
Lcd.setCursor(0,0);
Lcd.print(“LuxVal: ”);
Lcd.setCursor(0,1); 
Lcd.print(“ unit here”); 
Break;

//End the cases here then reset number of switch presses 

Continuity and bench test ( plus drilling the board )

Today I accomplished so much than what I was expecting. At the start of the lab I did all my best to improve the display ( Bench Test) of the LCD and everything went so well.

On the same day I drilled the board to hold all the components, which can be seen below in the picture.

The continuity test was done by using a multimeter; set on the lowest value of the resistance or under menu select the CONT function  and the beep indicated there is an closed circuit i.e. there is continuity.

Full System including Sensor/Control Board bench test.

As you can in the picture below, the room temperature value is displayed on the LCD because the cable is connected between them ( LCD and Sensor PCB ).

I also manage to do the calculations to get the light reading.  The LuxVal can been seen to be about 201.97. 

Hit: This is the light reading when I was working inside my room; not outside.  

The FAN/Motor

I drilled holes on the back where I placed the fan. Because to let the air out, therefore, cooling the temperature down. 

In my code I declared that the fan will go high only when the temperature exceed 24 degree Celsius. This value can be changed to whatever suits you best.

Finish soldering the components on the PCB(s)

In the picture below, it can be seen that the LCD board, Sensor/control board and the fan/motor are all ready to go. But I have to do the continuous test on the Sensor board. All the components seem in the right place and I can be sure of this because I used the schematic to verify everything. 

Sensor and Control board Schematic

LCD - Liquid Crystal Display ( Displaying Temperature in degree Celsius )

 The first image shows the welcome message 'Kings B0092297' which stand for my student number (B00092297)

This was the random temperature when I connected the Arduino Uno on the LCD board. I am so glad that I converted it into degree celsius as the output temperature.

Image 3 is just showing the back of the LCD board with the Arduino Uno attached to it.

The Complete LCD

The soldering went wonderful and now I am working on the Arduino code to make the LCD display the Welcome, Temperature, Light and Humidity readings. As you can see below, the Welcome is displayed using the Arduino cable only. The switch 2 acts as the Mode Select. Meaning it will display different readings as you press it each time.

This is the LCD schematic below:

LCD PCB and the Photodiode ( Light Sensor )

LCD board:

This was giving to each pupil in the lab after signing the agreement paper. One has to reflect first before putting components on this board, because there is only a single board for each pupil. Therefore, making a mistake here is like a none returning point. caution is necessary when soldering this LCD board.

LDD(Light Dependant Diode)/ Photodiode ( Light Sensor ):

The Photodiode below in the picture is the one I used on the Sensor/Control PCB in order to measure the level of light ( in Lux). It was quite hard to identify which side is the cathode and the anode. By doing a little research I found out that the white bar line ( which can be seen in the picture below ) is the cathode ( Negative ). knowing this at the start of soldering the components into the Sensor/Control board was the most essential thing to me.

The Artwork Design

PRINTING OFF THE PDF.

The board came out fine, but the name was inverted. Meaning I made a little mistake at the beginning ( using the UV light). Therefore, I am required to go over it once again. It takes a lot of patience to get the finished piece and I will not give up until I get it right.

I understand that it's not about finishing first, but it's all about getting everything working at the end!