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intermediatePCBs & Circuit Design28-Jan-2019

Custom Shaped PCB (Instructable Robot)

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1 weekend

$10-30

Original Project by YADUKRISHNAN K M from Instructables.

Source: https://www.instructables.com/Custom-Shaped-PCB-Instructable-Robot

License: Attribution-NonCommercial-ShareAlike

I am an electronic enthusiastic. I made a lot of PCB. But most of them are the regular rectangular shaped. But I saw some custom designed PCB in most of the electronic equipment. So I try some custom designed PCBs in earlier days. So here I explain the making of a custom designed PCB. Here I use common tools for its preparation. Because, every electronic hobbyist do not have all the tools. So I use common tools here. This custom designed PCB is fully home made one. It help you to understand more about the PCB design. Here I use Instructables Robot as the PCB design and add some led illumination work to the PCB using SMD components. In the future steps I explain more about it. So lets go...

Steps

Components Needed

Here I use the SMD electronic components from old PCB. It reduce the project cost. You follow this method or purchase the components.

Copper clad

FeCl3 solution

PCB cleaner

All components are SMD

Resistor

Capacitor

Led

DC connector

All component values are given in the circuit diagram.

The images are given above.

Tools Needed

Here I use the common tools. The main tools are an micro soldering iron and an ordinary soldering iron. The complete list is given below,

Miro soldering iron

25 W soldering iron

Small knife

Hacksaw blade

File

Small screw driver

Flux

Solder wire

etc...

Circuit Design

Here I use an dual op amp. IC. It is wired as an oscillator to produce low frequency oscillation to blink an LED. The 2 op amp. work independently and produce square wave signal. The two oscillator wired same manner to produce same signal. It is because otherwise we need to add a transistor to boost the current. Here it is not used because to reduce the complexity. So the LEDs drive by the 2 op amps. So current problem avoided. The circuit drawn in the 'spice' software. The circuit given above.

PCB Design

It is a small circuit. Because the PCB design is very simple. So normally it do not need the PCB design software. Software are used for complex circuit design. But here I use a PCB design software to study the PCB design using software. The above image shows the PCB design.

Custom PCB Shape Design

Here first I download the instructable robot image. Then covert it into drawn image by using image filters option in the Photoshop image editor. Then the images print into a paper for reference. The image size is same as the PCB size. This given as PDF file in below. Then I combine the robot image and the PCB design into a single image. This is used to mask the copper clad for etching. By this we get the circuit traces and the robot image in the copper clad. The images are given above.

PCB Processing

In this step, we clean the PCB copper side by using the sand paper and reduce the thickness of the copper clad by using the sand paper and the file. The procedure given below,

• Take the copper clad

• Reduce its thickness by using the sand paper

• Clean the copper side by using he sand paper (400)

• Clean the copper clad using water and dry it

Applying Mask for Etching

Here in this step we apply masking on the copper clad for etching. The masking provide the circuit layout to the copper clad. This will avoid the etching at the masked portion. So the etching done only at the unmasked portion. By this made the copper tracks on the copper clad. The masking procedure given below,

• Print the PCB layout on a glossy paper (or magazine paper)

• Stick this with the copper clad

• Apply heat on the paper by using iron box

• Remove the printed paper

Now the PCB layout is copied to the copper clad

Masking by Using Permanent Marker

It is the simplest method for creating the etching mask. Here we only use the permanent marker. It makes that, this method useful for any electronic beginner. In this way, we draw the layout in the copper clad by using the marker only. The steps are given below,

• Take the copper clad

• Cut the robot image

• Draw the robot image by cutting each parts separately as shown in the above images

• The draw the PCB layout in it

• Then darken the mask by redraw the complete layout once again

• Check the circuit layout

• If any short circuit in it remove it by using the small knife

Etching

The etching is the removal of unwanted copper parts from the copper clad. By this method we create the circuit layout in the copper clad.The given procedure explain the etching process.

• Wear gloves to protect our hand

• Take some water in a plastic plate

• Add some FeCl3 to the water and mix it very well

• Immerse the copper clad in the FeCl3 solution

• Wait for some time (as your solution concentration)

• Check continuously for successfully etched PCB

• After etching clean it by using water and dry it

Mask Removal

Here we remove the permanent marker ink. For this first clean it by using soap water. Then using sand paper clean it and wash with clean water. Then dry it.

Drilling

We need some hole to place the DC connector to it. This is the only through hole component in it. All others are the SMD components. It do not need any holes. For drilling I use a hand driller. Very small bit is used for drilling. Drilling starts from the copper side. Do not apply extra force. It will damage the PCB.

Solder Mask

In this step I apply a coat of solder to the full copper traces like a mask. It will increase the beauty and it will protect the copper from corrosion. The copper react with water and air. So the solder will isolate it from the corrosion causing agents. For this First apply flux to the traces. Then make solder layer by using the micro soldering iron and solder wire. Then smooth it by using 25 W soldering iron. Then clean the PCB by using PCB cleaner solution.

PCB Custom Cutting

Here we cut it into the Instructable robot shape. It is done by the ordinary tools like hacksaw blade, knife, file etc... The procedures are given below,

• Using knife draw a line to which cutting is follows

• Remove unwanted corners of PCB by using hacksaw to make a rough shape

• Then by using the small knife make the original shape

• Finally smooth the edges and finalize the shape by the use of a file

• Clean the PCB

We done this step.

Testing the PCB

It is one of the main step in the PCB manufacturing. Here we check the continuity of each track with respect to the circuit diagram and check for unwanted short circuit.

• Turn the multi meter knobs into the continuity check mode

• Using the probes check the continuity of each track and compare it with the circuit diagram

• Also check the possibility of short circuits in the unwanted position

• If it done successfully go to next steps otherwise fix the problem

Worth Desoldering

Here I use the components from old PCBs. It will reduce the project cost and it will help you to study more about the electronics. This process increase our electronics knowledge. You choose this method or purchase the components. The de-soldering procedure shown in the above video. After the de-soldering, text the components using multi-meter and use it for this project and future projects. OK. Good luck.

Soldering

This is the time for soldering. Here I use a micro soldering iron. First solder the IC and then the rest of the components. Do not apply extra heat. It will damage the IC. Solder the LED with care. Because it is heat sensitive. It will damage very quickly. The procedure is given below,

• Use micro-soldering iron and the tweezers for soldering

• Apply the flux to all the points where the components placed

• Place the component using tweezers and solder its leg by using micro soldering iron and the solder wire

• Double check the components polarity

• Finally check the components soldering and verify the circuit using circuit diagram

• Clean the PCB by using the PCB cleaner

We done this step successfully.

Circuit Testing

Now it is the time for circuit testing and debugging. Connect a 9 V battery to it by using a male connector suitable for the PCB DC connector. If it is not blinking check the connections and the IC. Then check the LED. By completing the debugging section successfully, we get a good model of working Instructable robot.

Conclusion

Find a suitable place to fix it. Switch on this robot at a dark room and observe the beauty. You choose this as a key chain or a locket.

Are you like it ??? Please comment in the comment secession..

Bye,....

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Downloads

Custom PCB Shape Design - New Microsoft Word Document.pdf

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Custom PCB Shape Design - New Microsoft Word Document.pdf

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