Task to be carried out this week

Action Plan

Introduction to Electronic Components and Electronic Design

Electrotronic Components:

1. Ribbon Cable:A cable for transmitting electronic signals consisting of several insulated wires connected together to form a flat ribbon.

2. IDC connectors: Insulation-Displacement Connector(IDC) are electrical connectors designed for ribbon cables and telecommunications applications. They are also referred to as insulation-piercing contacts (IPCs).

3. Buttons:Buttons and switches are among the most basic but necessary components in an electronic project. They can be of many types such as slide switches, push button, toggle button, rotary switches, etc.,.

4. Printed Circuit Boards(PCB):A printed circuit boards (PCB) are foundational building block of most modern electronic devices. It is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate.
There are two ways to add components on PCB:

1. Through Hole Technology(THT):
This is known as the original assembly process. In through-hole PCB the components run through the board. Thus, making the connection stronger and allowing the components to withstand more environmental stress.
2. Surface Mount Devices (SMD):
In Surface Mount PCB, the components are secured only by solder on the surface of the board. However, SMD are more efficient and cost-effective. This is also the type we use in Fab academy.

When it compes to the production of PCB, there are two types of PCB production process

1. Chemical Etching:
This type of PCB production process is mostly used for industrial production. In this process the copper from a circuit board layer that is not protected by the hardened photoresist is removed by immersing it in a chemical solution. The chemicals used are usually hazardous, thus specific precautions must be taken when using this process.
2. PCB Milling:
PCB Milling also known as isolation milling is s the process of removing areas of copper from a sheet of printed circuit board material to recreate the pads, signal traces and structures according to patterns from a digital circuit board plan known as a layout file.Similar to chemical itching, the isolation missiling is a subtractive process where by the materisal is removedto create the electrical isolation and ground planes required. However, isolation milling is a non-chemical process.

5. Resistors: Resistors are current limiting components. It can be calculated using the following formula;
Resistor(R)= Voltage(V)/Current(I)
R=V/I

6. Capacitors:Capasitors are electronic component that stores electric energy. They are usually used as filter to prevent noise and fluctuation in the electric current. When an electric voltage increases, the capacitors charges up and when an electric voltage decreases, the capacitor releases electric energy.
Types of capacitors:

1. Polarized:
Capacitors having polarity i.e., having a positive and negative side. These type of capacitors usually have high value.
2. Non-Polarized:
Capacitors with smaller value which doesn't have any polarity.

7. Crystal, Resonator

1. Crystal Oscillator
An electronic oscillator type circuit that uses a piezoelectric resonator , a crystal, as its frequency determining element. The crystal is a common term used in electronics for the frequency-determining components, a wafer of quartz crystal or a ceramic with electrodes connected to it. They produces a periodic oscillating electronic signal often as sine wave or a square wave or a triangle wave
2. Resonator:
A device that exhibits resonance or resonant behaviour. resonators are used to to either generate waves of specific frequencies or to select specific frequencies from a signal.

8. Inductors:An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it

9. Diode: Diode is a two-terminal electrical component that allows the flow of current in only one direction;it has low resistance in one direction, and high resistance in the other. In circuit diagrams, a diode is represented by a triangle with a line across one vertex. The two sides of a diode are called Cathod(-ve) and anode(+ve) respectively. Diodes are used to protect circuits by limiting the voltage and to also transform AC into DC.
There are many types of diode but the most commonly know are:

1. P-N junction diode
Also known as rectifier diode, P-N junction diodes are used for the rectification process and are made up of semiconductor material. P-N junction diode includes two layers of semiconductors. One layer of the semiconductor material is doped with P-type material and the other layer with N-type material. The combination of these both P and N-type layers form a junction known as the P-N junction. Hence, the name P-N junction diode. P-N junction diode allows the current to flow in the forward direction and blocks the flow of current in the reverse direction.
2. Zener diode
Diodes that allow current flow in reverse direction under certain voltage. They are widely used in power supplies to provide a reference voltage.
3. Light Emmiting Diode(LED)
Diode that produces light when electric current passes through them. They are vaialable in multiple colors and are widely used in electronic projects

10. Transistors: A transistor is a semiconductor device used to amplify or switch electrical signals and power. Transistor is a three terminal device and a small current / voltage at one terminal (or lead) will control a large flow of current between the other two terminals (leads).
Broadly transistors can be classified as follows;

1. Bipolar Junction Transistors(BJT): BJTs are essentially current-controlled devices with 3 terminals namely; base, collector and emitter. If small amount of current flows through the base of a BJT transistor, then it causes a flow of large current from emitter to collector.
2. Field Effect Transistor(FET): FET also have three terminals (like BJTs). The three terminals are: Gate (G), Drain (D) and Source (S). The Field Effect Transistors are uni-polar devices, as they require only the majority charge carriers to operate (unlike BJT, which are bipolar transistors).

12. Battery: Battery is a device that convert chemical energy directly into electrical energy. In an electric circuit, battery is a source of energy which provides a push - a voltage - of energy to get the current flowing in a circuit.
Electric current is generally of 2 types;

1. Alternating Current(AC):In alternating current the flow of electrons switches back and forth at regular intervals or cycles. Eg; Current from transmission lines
2. Direct Current(DC):In direct current, the current flows consistantly in one direction. Eg; Current from battery, solar panel, generator etc.,.

13. Adaptor and Inverters: Adapters are devices that converts AC to DC and Inverters are devices that converts DC to AC

14. Microcontroller: Also known as a microcontroller unit(MCU) is a compact integrated circuit designed to govern a specific operation in an embedded system. A typical microcontroller includes a processor, memory and input/output (I/O) peripherals on a single chip.

PCB circuit design using Autodesk Eagle Software

Autodesk EAGLE is a scriptable electronic design automation (EDA) application provided by autodesk company. EAGLE stands for Easily Applicable Graphical Layout Editor. It provides options to create schematic as well as board circuit design. The schematic files are saved with .sch extension and board files as .brd files. We can also export the board files as .png image files. I had learned basic electronics in my college days, but I had forgotton most of it. I had to re-learn most of the things but I was able to grasp easily. This was the first time I used the eagle software and I found the process to be quite interesting. However, I faced trouble when trying to arrange the components in my board design. I found this part to be quite difficult and confusing

To begin, I forst installed the eagle software. Once I was done with the installation, I downloaded the fablibrary from the GIT account. Fab library contained most of the electronic components that we were to use in fab academy and for the week's assignment. I extracted the libraries from the downloaded zip folder. Next,I opened the eagle software and created a new file.
To do that open eagle software → Click on files → new → Project and name your project.
Now once the project is created, go to files → new → schematics to create the schematic diagram of the circuit.
Next, I had to add the fab library to the project I created. To do that
Go to Library → Open Library Manager → click on browse → select the fab library → click use.

Once I was done with setting up the library, I started to draw the schematic diagram for eco-hello board. To add the components, type 'add' on the text bar as shown in image below. On entering, we get a pop-up box displaying all the components. Since we have already added the fab library, we can now use the components available under fab library to draw our schematic diagram of the echo hello board.

For making my echo hello board, I used the following components;

1. Microcontroller: ATTiny 44
2. Resistor: 3 resistors
3. LED
4. Capacitor
5. Resonator
6. AVRISPSMD
7. FTDI-SMD-Header

Next I ran the Electrical Rule Check(ERC) to test the schematic for electrical errors. To do that Go to Tools → Click on ERC. A pop-up window will be displayed that shows the errors and warnings. we can try to rectify the errors to ensure the circuits function properly.

This was the final schematic design I made.

Next I generated the board design from the schematic design. To do that click on the icon as shown below. Once I generated the board design, I moved all the components to the design window of the board design. I stared arranging the components based on the best possible fit. Then I manually routed the connections. There were a couple of design rules I had to keep in mind when routing. First, I had to change the trace width to 16. I could do that by clicking the width option in the task bar above the design window. Our lab instructor informed us to ensure that no traces/routes run in between the controller pins and no more than 2 routes should run under any components. I started routing and it took me an entire day and a half to optimize my board design to 100%. I had to add a zero ohm resistor to optimize my routinng. In the week's assignment, I found this task to be the most difficult and it required a lot of patience which I lacked. However after trying for a 100th time I was finally able to design my board diagram. Following is the final board design I made;

I believe the the design is still lacking and need better routing but I am happy that I was able to atleast fulfill the basic design rules and create the a functional board diagram. I hope to improve my skill as I keep using the software Next I exported the board design as .png file. Before exporting, I removed the labelings on the components. This needs to be done to avoid issues when milling the pcb. To do that;
Go to view option → Select layer setting → hide all the layer except for dimensions layer for border traces and top layer for design traces.
To export the design go to Files → export → select image → name the image the save. We need to save the border file and traces file seperately. Please ensure to save the image file with a minimum resolution of 1000. I didn't change my resolution in the begining and it gave problems when milling.

Printing the Echo Hello board

For printing my echo hello board, I followed the steps used during the Electrinic production week. I printed my board using the Roland SRM20 machine and used MIT Mods to create the machine readible .rml file. I tried printing my board but it didn't get printed well. The milling was not done properly.

This happened because I have saved my image file with very less resolution. Thus, I created a new .png image file with highter resolution and printed the board again. This time the board was printed cleanly. Once I was done printing my board, I started with the soldering process. I soldered the components on the board following the steps and process learned during week 4. This was the final board after soldering.

Programming my echo hello board

\

The second part of the assignment for the week was to program the echo hello board. We used audrino as programmer to program the echo hello board. To do that, I had to first undertand the pin layout of the arduino and ATTiny 45. I found the pin layout online and I followed the layout to make connection between the arduino and ATTiny 45 microcontroller. We used the Arduino IDE software to program the board. Before programming, we had to first select arduino as the programmer in the Arduino IDE. To do that;
Go to Tools → Programmer → select Arduino as ISP.

Next we have to choose the board to be programmed. Since our board option is not available on Arduino IDE, we need to download and add the board to the Arduino IDE library. To do that Go to Files → Preferences → paste the ULR for additional board manager. The file for the additional board manager can be found on Github

Now that the board is available on the Arduino IDE, we select the board to be programmed, th Arduino ISP as the programmer, ATTiny 44 as the processor and set the clock to 1MHz on Arduino IDE.

Next we use the following program to check if the board is programable or not. We use a simple LED blinking program which is already available under examples on the Arduino IDE. I just had to change the output pin number.

This was the video of the working programmed echo hello board.

Assignment Files

Click to download the schematic diagram Click to download the board diagram Click to download the code for blinking LED