Fifth day, Wednesday (11/07/2012)

Assalamualaikum and peace everyone who still follow my blog. I’m gladly still health and can continue my work, so thankfully to my god that give me healthy body. From my last task in previous day, my supervisor has ordered to understand about AT command in GSM Modem. So today they have given GSM Modem to me to try it out. 3 people are in charges and they are Rahmah, Syuhada and included with myself. The tasks are sending SMS and receive SMS. For the future task, we need to combined with programmable PIC to send the information to the owner by SMS and owner can control the circuit by send SMS back and the PIC will execute what been ordered by owner.

Before we go through more, there a theory that must to know it. Global System for Mobile Communications (GSM) is a technology for second generation (2G) digital cellular networks which is a replacement for first generation (1G) analog cellular. It described a digital, circuit switched network optimized for full duplex voice telephony. The modem is a device that modulates an analog carrier signal to encode digital information and also demodulates such a carrier signal to decode the transmitted information. Modem is attached to computers for ‘dial-up’ to connect with other computer systems.

GSM modem is a specialized type of modem that operates over subscription based wireless network which is similar to a mobile phone. It accepts a SIM card and basically acts like a mobile phone for the computer. Similar to modem operations except that it sends and receives data through radio waves rather than a telephone line.

Sending SMS

1.      Insert the valid SIM card into the SIM slot.

2.      Connect the GSM Modem to the supplied AC-DC adapter and also to the serial port of the PC.

3.      Select the correct COM Port in Hyper Terminal and set up the parameters as follows.

4.      Power on the GSM Modem and wait for it to initialize. While waiting, we can use the following command to make sure we can communicate with the GSM Modem.

AT <ENTER>

 

The GSM Modem should respond with “OK”.

5.      Once it’s ready, the following response will be received from the modem.

Call Ready

 

6.      Now we can start sending the AT command to the GSM Modem. Start by configure the modem to use Text Mode instead of PDU mode for the SMS. This mode allows us to send SMS using AT commands without the need to encode the binary PDU field of the SMS. Use the following command to put the modem in text mode and it should respond with “OK”.

AT+CMGF=1<ENTER>

7.      After that, we can send the SMS message with the following command:-

AT+CMGF=”0135219644” <ENTER>

        Replace the above phone number with your own number. The modem will respond with:-

>

        We can now type the message and send the message using the <CTRL+Z> key.

>TEST <CTRL+Z>

After few seconds, the modem will respond with the message ID of the message, indicating that the message has been sent correctly.

+CMGS: 49

  

AT COMMANDS TO SEND A SMS

TEXT THAT RECEIVE FROM MOBILE PHONE

Receiving SMS

1.      Set up the GSM Modem following step 1 – 6 in the previous section.

2.      Once the GSM Modem is ready, we can use a mobile phone to send a SMS to the modem.

3.      The following response received from the modem indicates a new SMS is received.

 +CMTI:"SM",1

The last character indicates the memory index number, we use this index to read or delete this message. In this case, the index number is 1.

4.      To list out all the available SMS in the SIM card, we can use the following command: 

 AT+CMGL="ALL"<ENTER>
              And the modem will respond with a list of SMS messages in the SIM card. 

                                     LIST SMS MESSAGE IN SIM CARD

 PROBLEM STATEMENT

 During the experiment we got a few problem such as:

1. After select the correct COM Port in Hyper Terminal and set up the parameters, then we need to power on GSM modem. This activity should be repeated when to send or receive SMS. If we just let the modem power on, we can't get CALL READY. So, my opinion it harasses jobs to do.
2. First experiment in sending SMS, we got an error occur like below: 

 it show that +CMS ERROR : 515. From the action has been taken, we try another laptop to test the GSM modem and try to change the SIM card. Finally, after a few laptop been test, we got to send SMS. After we analyze the problem, we need to push the  <CTRL+Z> key many time so they will appear +CMGS: 49

  

  From what we done today, we know the function of GSM Modem in sending and receive SMS. we also know to use the AT command for this operation.

Fourth day, Tuesday (10/07/2012)

Alhamdulillah, Thanks to Allah we meet again and I still go on my journey at UTeM Holding. For 4^th day during my practical at UTeM Holding, as usual I came at 9 a.m. and start preparing my blog to be update. After finish my updated, I continue my unfinished through hole soldering with ask to Mr. Mazran to supply the insufficient component. After I get the component I continue to finish my work. After finish and make an inspection at that work, then the next flow is to test the circuit were it is functioned or not. The tester equipment is vibrate sensor and LCD display.

VIBRATE SENSOR

This sensor been functioned as an input at AN0. When the sensor interfacing the vibrated, it will send the input to the PIC 28P by AN0 and connected to PIC leg number 2. The PIC are been programmed by PIC C Complier V4.038 where it been program to execute the LED to blink when it receive the input from vibrate sensor. PIC leg number 15 will connected to LED for the output. During my test time, I just shake the vibrate sensor to get the result (LED blink).

LCD DISPLAY

This LCD are been functioned to display what been programmed at PIC 28P. As usual the PIC must be set by PIC C Complier V4.038 to display what it required. During my test, my friend Azlan has set to write a “good” and when the supply been attach to the PCB, the LCD will display “good” means that my PCB been pasted. Since I not very similar to do a command at PIC with using PIC C Complier, that’s why I ask Azlan to help.

Figure show that the way to test the PCB with first circle show that the supply and second circle show the result for vibrate sensor. The LCD display will display the result.

After I’m finishing my work, Mr. Mazran give a task to understanding the AT command. He guide us to find the AT command with find it at cytron.com.my and then find the GSM modem, and then go to the manual. The page are about the introducing the GSM Modem, and the tutorial about control and monitor via SMS.   

 Third day, Monday (09/07/2012)

Firstly, thanks to god that I still can brief and continue my journey at this company. As usual, I come at 9 a.m. and continue the task that been given. The truth is, I still confuse to write the blog and if my supervisor sees my blog postdate seem that I been late to update do what he required. I hope he can forgive my lateness posted.so, we just continue what I have done in this day. From the previous day I been ordered to understand and do a Surface Mount Device (SMD) soldering. For today I still do soldering in the same PCB but in different way and component. For today soldering through hole components are my task. There is the component list and procedure of soldering at below.

COMPONENT LIST

1.      IC base for PIC28P and IC MAX232.

2.      5V relay.

3.      Capacitor 100µF and 47µF.

4.      Connecter.

5.       Power switch.

6.      Power connector.

7.      547 transistor.

8.      20k Cristal oscillator.

SOLDERING THROUGH HOLE COMPONENTS PROCEDURE

1.       Before we start soldering process, first thing must to do is check that all the equipment and component are been prepare.

2.       Then clean the soldering place at PCB area.

3.       Then insert the component into the plate hole with the right place. To avoid from component moved, secure it by cellophane tape.

4.       Place the soldering iron tip at the junction between the pad and component lead. Apply a small amount of solder at the junction of soldering iron tip and lead to make a solder bridge. Note that the size of the solder is important when soldering small components. If the solder is too large, it is easy to melt solder into the joint. If the solder too small, it can take too long to melt the optimum amount into the joint.

5.       Since a small amount of solder at the junction of soldering iron tip been applied, immediately feed solder into the joint from the side opposite from the soldering iron tip until the proper fillet is achieved. Remove the solder then remove the iron. The iron may be swept over the end of the component lead to cover it with solder. Noted that apply the solder to the side opposite from the soldering iron tip so that the work surface and not the iron will melt the solder.

6.       On multiple lead components solder the opposite corners first to stabilize the component. Follow by soldering the remaining leads in a random pattern to reduce excessive heat buildup in one area.

7.       Clean the flux residue, if required and inspect

CAUTION

·         Avoid exerting any pressure on the pad since the soldering iron tip at the junction between the pad and component.

·         A few tip from Mr. Mazran, make sure after do soldering process it is required to clean the soldering iron tip for better next soldering process.

SAFETY PRECAUTION

During the soldering process we must follow this precaution to avoid being an accident during work.

1.      Make sure that the shouldering iron is proper heat before do soldering process.

2.      Avoid touch the wetted flux and rod iron.

3.      Avoid smelling the smoke that come out from the soldering process and to avoid it, use anti-static absorber that can absorb the smoke and it filtered to the air.

4.      Always open the window during works.

5.      Make sure to turn off after use it to avoid in waste energy and accident.

6.      Use proper equipment which may cause of wound.

7.      To protect the component, don’t attach the iron to long at the components.

On this day I still can’t finished my work since that insufficient component and I have to wait next day to get the component. The components are Port B socket and 547 transistor.  During this day I update my blog to.

I'm starting my blog with assalamualaikum and salam satu Malaysia.

Firstly, I'm gladly thankful that been chosen to involve in internship program at this HIIS company. After what I through in my previous company, I hope this company will help me to expose working environment that will help do my internship program and related with my course of my studied. From what I saw in the schedule that Mr. Mazran plan to us, I will absorb that the objective of our training will be archived. 

Task schedule

Task	Member	Duration (week)
1.      Solar and Switching 2.      Microcontroller: -PCB/Soldering -Sensor Vibration -sensor sonar -GSM Modem	Parallel	1 – 4
PLC (GSM Modem)	Prerequisite: BENT	3 – 5
IP Camera ( 2 Set )	Divided 2 person per group
Mechanical Prototype (PLC / PIC )		6 - 10
Visual Basic	Website team	5

     

July 6^th, 2012

First day in UTeM Holding. We been briefing about our task by Farhan Bin Roslan about SMD (surface mount device). Then we try to practical it with the equipment and component that been given. The equipment are:

1. Solder Iron
2. Solder Paste
3. TGK-493 anti-static absorber (ionizer)
4. Tweezers
5. solder leads
6. Gripped board                                                                                                                               

And the components that will be solder it:

1. Power and reset button
2. 2 x GA 12 diode
3. PW LED and LED_C4
4. Resistor 2.2KΩ , 2 x 330Ω , 2 x 10kΩ   
5. Printed Circuit Board (PCB)
6. Capacitor 5 x 61µ 3

Surface Mount Soldering Process

Before starts to soldering process, we must know the procedure of surface mount components. Where the standard of staking adhesive which is acceptable, process indicator and defect with following Class 1, 2, 3 at the proper side. A good eye, a steady hand and a soldering iron with a small, clean tip are required.

First step:

-          Apply a small bead of solder to one of the PCB pads for the component to be installed.

-          The bead must be approximately 0.020 to 0.030 high.

Second step:

-          Using a pair of tweezers, pick up the component to be installed and place it over the appropriate pads.

-          With the part in position, move the soldering iron to the solder bead on the PCB pad.

-          Apply a small amount of heat from the iron to flow the bead, simultaneously lowering the part against the board and correcting for any rotational misalignment.

Third step:

-          Remove the iron and allow the solder to cool.

-          Inspect the joint. At this point, we just concern about the position of component and not the quality of the actual solder joint.

-          From the inspection, it must pass of class 1, 2, 3 standards.

-          The part should be flush against the PCB, with both ends properly contacting the pads.

-          The part should be straight, and centered between the two pads.

Forth step:

-          After third step end is soldering, go back to the original solder joint and reheat the solder.

-          The flux will allow the solder to flow freely and good fillet should be observed.

-          Add a little solder if it seems to be insufficient at solder joint.

Inspection from Mr. Mazran

            After we done surface mount device soldering. The work should be inspect to Mr. Mazran before continue the next process. Mr. Mazran will comment my work and give a useful advice to get a better work for the future.

Safety precaution

During the soldering process we must follow this precaution to avoid being an accident during work.

1.      Make sure that the shouldering iron is proper heat before do soldering process.

2.      Avoid touch the wetted flux and rod iron.

3.      Avoid smelling the smoke that come out from the soldering process and to avoid it, use anti-static absorber that can absorb the smoke and it filtered to the air.

4.      Always open the window during works.

5.      Make sure to turn off after use it to avoid in waste energy and accident.

6.      Use proper equipment which may cause of wound.

7.      To protect the component, don’t attach the iron to long at the components.