Etching process

Etching is a "subtractive" method used for the production of printed circuit boars (PCB). Acid is used to remove unwanted copper from the board. This is done by applying a "temporary mask" that protects the tracks from the acid and leaves the desired copper layer untouched on the PCB board. The equipment that used for this etching process are Ferric chloride liquid, plastic container and abrasive paper. The etching process are shown in figure below.

Added enough ferric chloride liquid at the bottom of a plastic container to cover the circuit board.

Put the board copper side up in the plastic container filled with ferric chloride liquid. Slowly shake the plastic container around 5-10 minutes.

It will be notice the copper begin to dissolve slowly.

This shake process will takes about 5-10 minutes  to make sure the unwanted copper off from the surface of the board.

After complete the procedures to etching the circuit board, the circuit board was washed using water.

At the same time, the circuit board must be scrubbed using abrasive paper to remove the unwanted toner.

The result after etching the board shown in figure below. 

Thicken the tracks on the circuit board

This procedure is important to make sure the tracks on the circuit board are connect with each other as designed and to make sure there are no problem occurs before start with etching process. This thicken process will touch it up with a permanent marker, though the permanent marker won't be as nice a mask as the real toner from the printer. Figure below shows the process to thicken the tracks on the circuit board. 

Before: 

During: 

After:

Produce the PCB circuit

The PCB design on the OHP paper will be affixed onto the copper board, the masking tape was used to fixed the design onto the copper board. The figure are shown below.

Then, the PCB was set on top of a cloth and the PCB will be heating by using dry iron. This is to make sure that the toner will melt off the paper, and stick onto the copper of the PCB. 

By referring figure above, the dry iron was pressed onto the circuit, and then pressing hard without moving the dry iron and hold the iron perfectly still for one minute and above and at the same time do not move the iron at all during this minute and push hard to make sure the toner will melt off the paper and stick onto the copper of the PCB. The result after iron the board shown in figure below. 

Equipment and tools used

Equipment and tools that used to produce the circuit. Below are the equipment and tools that are used.
1. Circuit board
2. Ferric chloride liquid
3. Multimark non-permanent marker
4. Abrasive paper
5. Masking tape
6. Dry iron
7. Pro'skit drill set

Below are the pictures of the equipment and tools that are used.

Print the PCB layout on the OHP paper (Overhead projector)

The design of a Printed Circuit Board (PCB) layout of the system was printed on the OHP paper. 

The picture of the PCB are shown below.

 

Figure: Printed mask on the OHP paper

                                              

                                                 Figure: Printed mask on the OHP paper

Design a PCB layout of DICM system

Design a Printed Circuit Board (PCB) layout of the system is important to combine all the components that are used in one circuit. To design this PCB layout of this DICM system, the DipTrace software was used. In this software, the main component is the Atmega 328 which acts as the control center or the brain of the system was added first before starting to design the PCB of this system. After that, other components such as IR sensor, solenoid motor, DC gear motor, DC motor sprinkler, LCD and buzzer was added together to the main component which is Atmega 328. The design a PCB layout of DICM system is shown in the figure below. 

By design this PCB layout, we know how to put or added the components and adjust the component and the tracks on the circuit board to make sure there are no contact with each other. This is important before we print the real PCB circuit and start with etching process. 

Redesign schematic diagram of DICM system

Before this, I had shown the schematic diagram of this DICM system. But now, I will add some component to my DICM system which is Liquid Crystal Display (LCD). The function of LCD that was added to this system is to show if there are some notification to the user of this DICM system. For example of the notification if there are run out of fertilizer and pesticide on the system. This added component is useful to give the information to the user. The new schematic design of this DICM system is shown in the figure below.  

By adding this LCD, it will give benefits to the user about their system.