All About Metal Clad PCB

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Hey Geeks, we all know normal Printed Circuit Board (PCB) which you see everywhere in electronics which is in green color. But there is a special Printed Circuit Board called Metal Clad PCB (MCPCB). This type of PCB have many names. We will discuss about that soon below.

Let me share my story when I came across this type of PCB (MCPCB) before I get into the main topic. I was designing a circuit which protects the Thruster from high voltage, short circuit, high starting surge current, etc. The  thruster which I was working with was T200 from Blue Robotics, which consumes maximum 30 to 35 Amps of current with 12 volts to 20 volts. So, my circuit design was completed virtually, made a prototype and tested in vero board with trace width and solder thickness accordingly with my manual calculation, estimated the thickness and the width of the track. Why I did manual calculation for this because most of the online trace width calculator works up-to only 35 Amps input. But I have designed my circuit in which the maximum load requires 105 Amps because I was using three Thrusters in parallel. My prototypes for single thrusters were totally perfect with all type of testing.

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Protection board for single T200 Thruster Prototype

After testing I was happy with my teammates juniors Arnab, Jayanth, Tony and Rahul who were worked and assisted me. Till this process I din’t think about the PCB designing process, so then started my PCB designing next day in Eagle CAD. Then I realized “OH SHIT WAIT” this board is going to carry 105 Amps and FR4 usual PCB material will be fried. That’s how ended up with Metal Clad PCB (MCPCB) after lots of research.

From my story, you might have guessed by now, where and why this Metal Clad PCB’s are widely used. Yes, it is used in where high current which dissipates high temperature heat. This type of PCB is widely used in Automobile industry where the circuitry works in high current and voltage. This also used in high powered LEds, solid state relays, motor drivers, etc. I just gave on of the main reason for using this type of PCB. I will discuss more reasons why this is used below.

And one more important thing is, this type of PCB literally having MANY name. I was confused while I was researching about it. So, don’t be confused. I ll put the other names for this type of PCB below.

  • Aluminium clad
  • Aluminum Base
  • Metal Clad Printed Circuit Board (MCPCB)
  • Insulated Metal Substrate (IMS or IMPCB)
  • Thermally Conductive PCBS

So, these are the names I came across for this type of PCBs. I love “Metal Clad PCB” name. So I will be using in this article and don’t get confused when you see these names somewhere else.

There are four types of Metal Clad PCB, they are,

  • Flexible Aluminium PCB
  • Hybrid Aluminum PCB
  • Multilayered Aluminum PCB
  • Through Hole Aluminum PCB

In this type of PCB, Aluminum is used but don’t get fooled by seeing “Aluminium” word in the names because Copper too used instead Aluminum. It might be little confusing what I am talking about. I will tell you in detail below about the design and construction of this type of PCB.

Basic Design & Construction of Metal Clad PCB :

Lets take single sided Metal Clad PCB for easy understanding. In this single sided Metal Clad PCB there will be three layers.

  • 1st layer or Top layer – Circuit layer
  • 2nd layer or Middle layer – Dielectric layer
  • 3rd layer or bottom layer – Aluminium or copper base

pcb_thermal_clad_budowa

The above image shows the three layers of Metal Clad PCB. These all three layers are put into a single piece. 1st Layer or Top layer – Circuit layer ; is a layer which is for circuit what we have designed. This circuit layer is compressed with a metal base (3rd layer or bottom layer) using a dielectric material (2nd layer or middle layer ; which won’t conduct electricity but conducts thermal heat).

The simple theory is, dissipating the heat generated in Circuit layer due to high current flow in the circuit in the PCB using metal clad or metal base (like a big heat sink to the whole PCB)  in  which the Circuit layer and metal base (Aluminium or Copper) is isolated using a dielectric material (Dielectric layer) which is very thin, highly thermal conductivity and high dielectric strength which allows to  guarantee of thermal endurance. This is the whole theory why and when this type of PCB is used. Because of the above reasons, it have high durability and more efficient.

The dielectric materials used in metal clad PCBs are mostly :

  • Polymer
  • ceramic
  • Epoxy
  • Boron Nitride
  • or combination of above

Thickness used in all three layers are mostly :

  • Circuit Layer : 35 micrometer to 140 micrometer
  • Dielectric material – 38 micrometer to 200 micrometer
  • Metal Base – 0.059 inches to 0.25 inches

One should be very careful while designing, and deciding the placement of the type of PCB because as usual PCB design ruins and makes the Metal Clad PCB fabrication complex and expensive. I will tell you what are the things one should keep in mind in detail below while designing. Placement is too important because the bottom layer will a conductive layer completely. So, one should give importance to decide the placement too, as you given to the designing.

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Types of Metal Clad PCB in detail :

  • Flexible Aluminium PCB : In this type of PCB, flexible polymide dielectric, flexible aluminum base is used. I have never seen this in practice. This can be bent few times. This is not used in applications like flexing the PCB regularly.
  • Hybrid Aluminum PCB : This is s type in which FR material and Aluminum base is sandwiched with dielectric material.
  • Multilayered Aluminum PCB : This multilayered Metal Clad PCB is very most expensive of all types, the only interesting thing in this is the vias, the blind vias are used for signal routing. If you are not sure about this type of Vias. I will post video explaining that.
  • Through Hole Aluminum PCB : This the type of PCB, I first designed in Metal clad PCB types and gave for fabrication. This is the very most complex design of all types of MCPCB. I would like to discuss this type in my YouTube channel in very detail.

Check the Video in my YouTube channel in which I show how dielectric layer looks like inside the Metal Clad PCB and much more. 🙂

 

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Brain controlled wheel chair – Version 0.1

IMG_6022Brain is the most important part of a Human Being, Whatever we’ve achieved today are the fruitions of the Human Brain. It is the Brain which controls our daily activities and behavior. The Human Brain can build trillions of thoughts and convert them physically, which represents our personality and behavior. So, by our “Brain Controlled Wheelchair” we try to present the functions which our brain offers and extend it further by combining  electroencephalography (EEG) technology and the ability of our beloved Brain. We are using this biosensor to sense the brain waves of the physically challenged people to actuate the particular work have to be done.

We decided to do research on this technology because this allows the person to control things in a certain limit without doing any physical work. We believe this research is important as this kind of technology will be of comfort to physically challenged people. It will allow the physically challenged people to control thing by just thinking, which eliminates the problems they’ve been facing.

images brain-stock

This brain controlled wheel chair is made possible by EEG sensor. We used Neurosky eeg sensor with dry-electrode, it senses the signals from the human brain, filters out extraneous noise and electrical interference and converts to digital power. This “brain-power” can be used in health and wellness, education and entertainment.

Made with Repix (http://repix.it)

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hardware used :

  • Arduino Mega
  • H bridge custom-made Motor driver
  • Four DC motors
  • And Lead acid battery 12v 7Amp

Softwares used :

  • NI LabView
  • Arduino
  • Mind Wave mobile core

Basic algorithm of this wheel chair :

flowchat

EEG Signals :

DELTA WAVES(0.5 – 3Hz)

  • Generated in deepest meditation and dreamless sleep.
  • Healing and regeneration are stimulated in this state.

THETA WAVES(3-8Hz)

  • The Light Meditation And Sleeping Wave
  • Present during deep meditation and light sleep, including the all-important REM dream state.

ALPHA WAVES(8 – 12Hz) 

  • The deepest relaxation wave.
  • Aids overall mental coordination, calmness, alertness, mind/body integration and learning.

BETA WAVES (12-38Hz)

  • The walking consciousness and reasoning wave.

But the algorithm involves only two parameters in this version 0.1 brain controlled wheel chair, they are

  • Concentration
  • Eye blink

That is in between delta and theta wave. In this no hardware filter is used because the neurosky sensor already have inbuilt filter which removes basic noise in the signal.

IMG_6023 IMG_6021


                                                                                                                                                                                                                                                                                                                                                              In this version 0.1 only forward and backward is made possible by very simple algorithm as you can see in flow chart. This allows very easy control on wheel chair by just thinking. As the algorithm uses two parameters for one single action as per the program, this gives very robust output in all condition.

Even if one parameter not matches with the algorithm the output signal from ardiuno to motor driver logic is zero. Only when the both parameters matches with the algorithm, then the motor rotates according to the program.

Motor Driver :

An H bridge is an electronic circuit that enables a voltage to be applied across a load in either direction. These circuits are often used in robotics and other applications to allow DC motors to run forwards and backwards.

The H-bridge arrangement is generally used to reverse the polarity/direction of the motor, but can also be used to ‘brake’ the motor, where the motor comes to a sudden stop, as the motor’s terminals are shorted, or to let the motor ‘free run’ to a stop, as the motor is effectively disconnected from the circuit.

H_bridge.svg

Components used in H bridge motor driver :

  • Mosfet (2 P CHANNEL)
  • Mosfet (2 N CHANNEL)
  • Transistor (2 NPN)

IMG_5703 IMG_6024

For this motor driver we used two type of cooling systems, the first one is heat sink which is attached to the mosfets. This helps the mosfet to cool by dissipating the temperature from mosfet by increasing the heat conducting area. The second is air cooling system, in this we used 12v computer fan above the four mosfets and other electronic components as a cooling system.

 Brain wave signal from Neurosky sensor :

brain signal

We have done a little effort for the physically challenged people whom the society has discarded (separated or created a boundary)

Every Homo sapiens have the right to fulfill their dreams, and why their disability should held them back.

So, i believe this brain controlled wheel chair will help the physically challenged people to fulfill their dreams and live happily.

Just like Lucid dreaming could provide the handicapped and other disadvantaged people with the nearest thing to fulfilling their impossible dreams: paralytics could walk again in their dreams, to say nothing of dancing and flying. Such sensorimotor practice could conceivably facilitate recovery from stroke, we can imitate and try to present the product to the people which satisfies their needs.

Everyone is born the same, but those who have the zeal, courage and an endeavor to pursue a positive attitude towards the life stays motivated and blessed by others.

“There should be no boundaries to human endeavor. We are all different. However bad life may seem, there is always something you can do, and succeed at. While there’s life, there is hope.”- S.H.

Check out the demo video here 😀



Man Following Robot

Man Following Robot is really cool robot, this is the first time felt the relationship between robot and me. After making this cool robot, I was totally got existed and inspired to make a robot which cares us and look after us when we are stressed in this day today busy life.

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This man following robot is totally based on image processing and basic electronics.

When we talk about the electronics involved in this robot is power layout board, 12v lithium polymer battery, two 20v high torque motors and two H-Bridge Mosfet motor drivers.

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While in other hand, image processing plays an important role in this robot to follow us. I have used basic color and pattern detection of my shirt to find me in the environment.

For image processing i have used,

—Logitech HD Webcam C310 is being used for Image Acquisition.

—It provides a Field of View of Approx. 42 degrees and pixel resolution of 1280 X 960.

—The Camera resolution is 720p.

images

As using both color and pattern detection, the robot is not very robust but this enables to follow us using color and patter. If we more robust the options are face detecting and laser sensing can be used to detect us in very robust condition.

The first step robot analyses the pattern and the color is available or not using the camera. If the camera detects the pattern and color in HSV type sequence of images.

The reason using HSV instead of RGB type of images is to eliminate the changing intensity value of the color due to sunlight or some other noise in the environment.

In simple world we extract the intensity of the color we want and save the pattern to search the both the values in the screen. The whole intensity of the color and the pattern is extracted by the value of each and every pixels involved in the color or pattern we desire.

The basic algorithm is as shown in the flow chart

chart

flowchat2

Applications :

  • Jogging

Woman-and-man-jogging-LP

5476_jogging-robot-l-120627-sbs

This Man following robot can also be used for jogging, we all love to jog in the morning and its very essential in our day today life. For improving the jogging and other sports activities there are many apps available which tracks our performance and enhances our jogging experience but this man following robot enhances our jogging experience in very different way. It like now opposite we gonna follow the robot. It helps to get in phase in jogging and gives us new level of experience.

  • Gives company while you walk :

This Robot not only enhances your jogging but also give a social company while you walk, imagine you are walking alone and the your following robot makes your walking time very interesting by poking you and playing around with you. I believe that this is going to be the very kind social robot which helps people not only by caring but also by enhancing the mood.

FEELING BORED?? CALL THE LOVELY ROBOT TO FOLLOW YOU AND HAVE FUN!!

Check out the demonstration of Man following robot for the first time . Its so fun to interact with the robot.

Gestural Interface Based Wearable Eyewear

Sixth Sense is a gestural interface device that augments the physical world around us with digital information and lets us use natural hand gestures to interact with that information. The Sixth Sense prototype is comprised of a wearable eyewear interface like Spectacles which have a projector and a camera embedded in them. Both the projector and camera are connected to the mobile computing device in the user’s pocket via Bluetooth. The projector projects visual information enabling surfaces, walls and physical objects around us to be used as interfaces; while camera recognizes and track user’s hand gestures and physical objects using computer-vision based techniques. The software program processes the video stream data captured by the camera and tracks the locations of the colored markers (visual tracking aids) worn at the tip of user’s fingers using simple computer vision techniques. The movements and arrangements of these aids are interpreted into gestures that act as interaction instructions for projected application interfaces. The maximum number of tracked fingers is only constrained by the number of unique wearable aids, thus Sixth Sense would also support multi-touch andmulti-user interface.

IMG_4649

This project deals with Electronics and image processing combination based on sixth sense technology to help the people to interact with technology in very easy way. This sixth sense technology helps the user to use the technology with physical action in the way of fun.

Technology in sixth sense

Various technology involved in sixth sense are as follows:

  • Electronics
  • Image Processing.
  • Classic mechanical design.

The SixthSense technology contains a pocket projector, a camera contained in a head-mounted glass wearable device.. Both the projector and the camera are connected to a mobile computing device in the user’s pocket. The projector projects visual information enabling surfaces, walls and physical objects around us to be used as interfaces; while the camera recognizes and tracks users’ hand gestures and physical objects using computer-vision based techniques. The software program processes the video stream data captured by the camera and tracks the locations of the colored markers (visual tracking fiducials) at the tips of the user’s fingers. The movements and arrangements of these fiducials are interpreted into gestures that act as interaction instructions for the projected application interfaces. SixthSense supports multi-touch and multi-user interaction

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 Electronics

The electronics part of the sixth sense eye glass contains 5 megapixel small camera in one side of the glass for acquiring the environment, Spice small mobile projector in one side of the eyeglass to project the computer screen in the hand or wall and Xbee is embedded in the one side temple of eyeglass which helps to communicate to the CPU of the computer and battery is placed very compact in another side of the temple of eyeglass and earphones are embedded in both temple tips of the eyeglass which helps to give a good quality of sound. These are electronics part of the sixth sense of the eyeglass.

Image Processing

Image processing plays a vital role in the sixth sense technology which helps the user to interact with the electronics gadget in a physical action, the image processing observes the hand movements and the hand gestures every second to process the action accordingly what the user wants, and the image processing not only observes the hand movements and hand gestures, it also observes the environments and gives all kinds of information of the environment.

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TASKS THAT CAN BE PERFORMED USING SIXTH SENSE

 

  1. Four colored cursors are controlled by four fingers wearing different colored markers in real time. The projector displays video feedback to the user on a vertical wall.
  1. The projector displays a map on the wall, and the user can control the map using zoom and pan gestures.
  1. The user can make a frame gesture to instruct the camera take a picture. It is hinted that the photo will be automatically cropped to remove the user’s hands.
  1. The system could project multiple photos on a wall, and the user could sort, re-size and organize them with gestures. This application was called Reality Window Manager (RWM) in Mann’s head worn implementation of Sixth Sense.
  1. A number pad is projected onto the user’s palm, and the user can dial a phone number by touching his palm with a finger. It was hinted that the system is able to pin point the location of the palm. It was also hinted the camera and projector are able to adjust themselves for surfaces that are not horizontal
  1. The user can pick up a product in supermarket (e.g. a package of paper towels), and the system could display related information (e.g. the amount of bleach used) back on the product itself.
  2. The system can recognize any book picked up by the user and display Amazon rating on the book cover.
  3. As the user opens a book, the system can display additional information such as reader’s comments.
  1. The system is able to recognize individual pages of a book and display annotation by the user’s friend. This demo also hinted the system’s ability to handle tilted surface.
  2. The system is able to recognize newspaper articles and project the most recent video on the news event on a blank region of the newspaper.
  3. The system is able to recognize people by their appearances and project a word cloud of related information retrieved from the internet on the person’s body.
  4. The system is able to recognize a boarding pass and display related information such as flight delay and gate change.

Benefits of this gesture interface based wearable eyewear are 

Entertainment:

This eyewear can be used for entertainment, the reasons why this eyewear will be advantage more than any other product now as follows

  • Easy to use with hand gestures and tapping
  • Makes your spinal cord healthier
  • Easy to follow instructions to make things
  • Navigation

Hand gestures and tapping:

Using the eye wear just by doing hand gestures and tapping will be fun and easy to use too especially in panic scenario.

tak

Taking pictures and video will be going to add more fun using hand gestures, which helps to take any scene without missing it, like as we miss to take some valuable and funny photos in a short time because of time to open camera in mobile.

This helps to helps to scan barcode, medicine info, book info, etc

Absent to class for weeks, missed all notes given by staff?  NO problem, Now you scan the notes to digital just by single tap.

In this product earphone and microphone is inbuilt, so u can hear music, can interact with the eyewear using voice interaction too.

Now we can watch movies, photos..etc. anywhere any time just in your hand.

Makes your spinal cord healthier:

We live in a time when mobile devices have become the de-facto of everyday life. Most of us check our phone several times a day, to check e-mails, send e-mails, surf the net, etc. Some of us watch movies on our tablets or read on our tablets or read e-books on our e-reader while on the go.

If you’re a mobile phone, tablet, or e-reader user, time to took up (literally). A new study published in the journal Surgical Technology International suggests that typically mobile surfing posture is the equivalent of placing a 60-lbs/ 27-kg weight on one’s neck.

spi

So this can be eliminated by the eyewear glass as this product helps to change the posture of surfing or watching movies, etc. on the go, now this product is making us happy and healthier too.

Easy to follow instructions:

Want to cook on your own, pull up the step by step YouTube video in your eyeball.

For following instruction in real time to make things on your own  this eyewear glass is the best.

cook

Navigation:

This eyewear is best tool for directionally challenged weather in your car, on you bike or hiking around. You get a permanent readout where you are and where you want to go.

navnav1

Surveillance:

The call for police accountability has led to a national push for body camera on cops. Two bills related to body cameras have been proposed in the Florida legislature.

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The same surveillance using camera can be used by this eyewear glass, the major advantage over the body cameras is that if the cop uses eyewear camera type surveillance he or she can able to record things what he or she see.And this eyewear can be used not only as a surveillance camera but it can also be used is many ways as a cop.

This helps for our Indian Cops to build a secure nation.

Electronic Security System.

This Electronic security system helps to lock the door, gives indication by alarm sound and red flash light when there is a theft occurs.

Everyone in the world strives to keep their life, property, and office space as safe as possible. We’ve worked years to build and maintain our life, businesses,etc. and when you leave, you want to make sure that everything is protected from harm and fraud. There are several ways to help increase the security at your home and business; one of the most effective is to install a Electronic security system.

work bench.
work bench.

The main highlight of this electronic security system is very cheap, so it is easy to install in home or office according to the demand.

The reason for the drop in cost of this system because, I am using Atmega16 instead costly ready made controller boards.

Components used :

  • Atmega16
  • led
  • buzzer
  • 100 ohm resistor
  • Scr ( Silicon controlled diode )
  • IR sensor
  •  9v 1.5 amp battery
  • servo motor
I made my hostel room as a mini electronics lab.
My hostel room as a mini electronics lab.

In this system, I have used one IR as a sensor in input and led, buzzer, and servo motor as actuator in the output of the ATmega16 micro-controller.

This security system will be activated according to the IR sensor, when the IR sensor is disturbed then  the sensor gives analog voltage to the micro-controller, then the micro-controller converts analog signal to digital signal and this digital signal is again convert into analog and actuates the buzzer and led which is connected in the output pin of the micro-controller.

For continuous alarm, even if the IR sensor is not disturbed after its disturbed state, I have connected SCR ( Silicon controlled rectifier) in forward bias in between the output pin and actuators.

characteristics of SCR.
characteristics of SCR.

NOTE : I used gate triggering technique for the continuous output signal.

FEEL SECURE, BE HAPPY .

Check out my demonstration of Electronics security system right after finishing the circuit and programming.

Line Following Robot

2014-02-01 08.38.16

Line following is very basic and important for the further involvement in autonomous robots as it covers basic control system with more number of sensors. And recently a restaurant name called Wall E in china serving the food to costumers using robots in which the navigation to each and every table is done by using line following technique. So, I believe line following robot is very important for robotic geeks out there. This is line following robot which I made in the year 2013 , one of the main point to highlight in this line following robot is, the entire robot will cost very low.

Components used in Line following robot :

  •  ATmega16 micro controller
  • Two IR sensors ( four which I used for competition )
  • L293D motor driver
  • Two 300 rpm dc motor
  • one caster wheel
  • voltage regulator 7805
  • 9v 1amp battery
  • A switch
  • chasis
  • two wheels

The main reason why the cost become down is, because I used Atmega16 instead of Arduino or raspberry pi. The normal C programming is used in this robot in AVR platform. lemalabs

First I have regulated the voltage from 9v 1amp battery to 5 volt using 7805 voltage regulator because the Atmega16 requires only 5 volt to perform its task and to power it on. Then the output pins are given to motor driver L293D and the output are give to to the 300 rpm dc motors. Then the 12v is given to the motor through the L293D motor driver. The IR sensors are given to Analog to Digital converting input pins, now according to the IR sensors output, the micro controller ATmega16 gives the command to the motor driver L293D , now again according to the motor diver’s output the wheel rotates. This is the basic overview actually whats happening in the line following robot. Checkout my first line following testing video

Manual controlled Robot

My first robot which I made is manually controlled robot, the mechanical design and the wiring all done in home on 17th Sep 2013.

2013-09-17 23.35.56

Mechanical Design :

The reason why I have chosen track type instead of normal wheels is for a better navigation in all type of rough condition without any difficulty. As I am an Electronics Engineer, took military tank as a reference for mechanical design of the robot.

2013-09-17 23.32.34

Electronics and Wiring :

I have used four gear type motors 400 rpm high torque motors which provide a good torque for the robot. And the motors pairs are connected in parallel to maintain the same speed in both the motors so that the voltage will be maintained same to provide same speed, which helps the to maintain a constant path without any drag.

Control :

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For control normal two DPDT switch is used , by which we can able to controll the robot the direction left , right, straight and even 360 degree turn.

Finally, I learnt that mechanical design is very important in all case as a Electronics engineer.

Checkout the video in which tested this robot for the first time right-after it got finished.