Even though i have studied Electrical & electronics engineering, my main focus subject was electrical. So i was not much familiar with designing electronics circuit.This was the main reason why i joined Fabacademy. So instead of copying others work i thought i would start from the basics. So i started reading electronics tutorials, youtube videos

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I started from www.allaboutcircuits.com , www.electronics-tutorials.ws

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Study basics on electric circuits

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About diodes

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Pull up/Down resistors

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I gained an idea on electronics, diodes, pull up/down resistors after watching these tutorials So i decided to build a personal assistant/assistants with the shape of an owl in fusion 360

Pull up resistors

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These resistors are used in digital logic circuits to ensure a logic level at a pin, which results in state wherein the input/output voltage is nonexistence driving signal. Digital logic circuits consist of three states like high, low and floating or high impedance. When the pin is not pulled to a lower or a high logic level, then the high impedance state occurs. These resistors are used to solve the problem for the microcontroller by pulling the value to a high state.When the switch is open, the microcontrollers input would be floating and brought down only when the switch is closed.

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Pull Down resistors

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As pull up resistors, Pull-down resistors also works in the same way. But, they pull the pin to a low value. Pull-down resistors are connected between a particular pin on a microcontroller and the ground terminal. An example of a pull down resistor is a digital circuit shown in the figure below. A switch is connected between the VCC and the microcontroller pin. When the switch is closed in the circuit, the input of the microcontroller is logic 1, but when the switch is open in a circuit, the pull down resistor pulls down the input voltage to the ground (logic 0 or logic low value). The pull down resistor should have a higher resistance than the impedance of the logic circuit.

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LED -characteristics

Light Emitting Diodes are semiconductor devices that convert electrical energy into light energy. Light Emitting Diodes are made from exotic semiconductor compounds such as Gallium Arsenide (GaAs), Gallium Phosphide (GaP), Gallium Arsenide Phosphide (GaAsP), Silicon Carbide (SiC) or Gallium Indium Nitride (GaInN) all mixed together at different ratios to produce a distinct wavelength of colour.

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The above figure is a typical led connection where .Rs is the Series resistance ,Vs is the source voltage,Vf is the forward voltage of the LED(also referred to as the "voltage drop") ,If is the safe current through the LED

So we have

Vs = supply voltage =5v

Vf = 1.8V

If = 18mA

So Rs = (5 - 1.8)/(.018) = 177.77

The closest resistor having a greator value than this in our lab is 499 ohm . i hope may be this work with a reduced brightness.

Logic Signal Voltage Levels

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TTL gates operate on a nominal power supply voltage of 5 volts, +/- 0.25 volts. Ideally, a TTL “high” signal would be 5.00 volts exactly, and a TTL “low” signal 0.00 volts exactly. However, real TTL gate circuits cannot output such perfect voltage levels, and are designed to accept “high” and “low” signals deviating substantially from these ideal values. “Acceptable” input signal voltages range from 0 volts to 0.8 volts for a “low” logic state, and 2 volts to 5 volts for a “high” logic state. “Acceptable” output signal voltages (voltage levels guaranteed by the gate manufacturer over a specified range of load conditions) range from 0 volts to 0.5 volts for a “low” logic state, and 2.7 volts to 5 volts for a “high” logic state:

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EAGLE

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Autodesk EAGLE is an electronic design automation (EDA) software. Enabling printed circuit board (PCB) designers to seamlessly connect schematic diagrams, component placement, PCB routing and comprehensive library content.

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Eagle has got many inbuilt libraries. The libraries that can be used with fablab can be accessed here fablibrary

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Open Eagle and create a new project and name it.

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Open Schematics to start drawing schematics

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Load the fab library which was downloaded earlier. Click on Manage library and add the library by browsing to the file

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The tutorial from fabacademy docs link here really felt very much useful as it explained a lot and was a hand book for the week, i found that it was very well explained. So i decided to followed the same.

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Add different components as required from the schematic in above tutorial

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Arrange the components and trace the path using tool 'net'

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s Next to connect two components, NET -- NAME -- LABEL (so you'll need a net on both the component itself and the microcontroller pin as well)

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After checking the electrical connections switch to board mode, the components in the schematic will be placed automatically in board mode. Rearrange the components and from 'Edit' choose 'Design rules'. Choose clearance, distance etc and change it to "16 mil" as below since we are using 16 mills drilling bit.

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The autoroute function can be used to route the traces automatically, as derived from schematic drawing. It could also be traced manually

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After autorouting, if there is completion below 100% then click 'evaulate' for errors.Fix the errors and continue autorouting until there is 100 % completion

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After 100% routing add name outer line etc in different layers as shown below.

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Select the different layers and export the file as png

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Download the file here

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File no.1

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File no.2

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Prepare the MDX 20X mill for milling

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After milling and tracing the output board will be as below

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The components were arranged for soldering to the board. The soldering station was also set

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After soldering the components to the board,i decided to program using my USBattiny ISP which was made as previous week assignment.

Since i used windows pc, before programming with the Usb attiny ISP, i downloaded the necessary drivers,WinAVR for windows. I used GIT bash for executing the linux commands in my windows PC

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GIT BASH

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Since coding in arduino IDE was simple i thought i would use the same

But as the arduino doesn't support the attiny44 board for programming, i added it using the board manager. The file shown in the link below was added to the board manager

https://raw.githubusercontent.com/damellis/attiny/ide-1.6.x-boards-manager/package_damellis_attiny_index.json

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Attiny to arduino Map

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Pins of attiny44

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The sample program 'Blink' was selected. The output pin was changed as per my schematic to pin 7. The button was connected to pin3. In arduino the pin 7 was configured as output and pin3 was configured as input. The arduino program is as below:

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Upload the code to the board, output is as below

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DESIGN FILES FOR DOWNLOADHERE

GROUP ASSIGNMENT

The group assignment was to test the equipments in fablab with the microcontroller get familiarised with them. I used the equipments and multimeters to test the errors occured in the echoboard i justmade for which i was not getting output initially

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The group assignment was to test the equipments in fablab with the microcontroller

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Instek GPD-3303D

The GPD3303D is a 3-channel multiple output programmable linear DC Power Supply contain the superior technology and high quality which GW Instek had established through its long history of power supply design and manufacturing.

• Tracking Series and Parallel Function : Tracking series and parallel function allows you to use the GPD-3303D in a wide range of applications. The tracking series mode guarantees higher output voltage, while the tracking parallel mode guarantees higher output current.
• Convenience Functions: The GPD3303D knobs are digitally controlled, allowing for fine or coarse volume settings. The key lock feature locks panel operations, preventing accidental settings changes, which might damage the equipment.
• 4 Sets of Save/Recall: The GPD-3303D can save and recall panel settings; quickly select a panel setting from the four memory sets without the need for manual configuration.
• USB Remote Control: The USB device port in the GPD3303D allows you to remotely control the power supply according to your application needs.
• The dc spply was used to power up my LED in the circuit and check whether it's working

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UniSource DS-1100 100 MHz, 2 Ch, Digital Storage Oscilloscope

I chose digital storage oscilloscope to check the output of my pins ,since i was not getting output from the LED. following are the specificaions of the oscilloscope

• 100 MHz bandwidth, 1 M Memory
• High resolution color LCD display
• USB storage, RS232C & J45 interface
• 4000 point record length for each channel
• Multi-waveforms math, FFT Function
• Built-in delay sweep function
• Automatic Multi-waveform Measurement
• Cursor & Track measurement
• Waveform Record & Recall, Trigger Mode for Edge, Video, Pulse Width, Slope & Alternate
• Display of date, clock and help information
• Also available in 60 MHz DS-1065, 100 MHz DS-1200

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AFG-2100/2000 Series Arbitrary Function Generator

The AFG-2100/2000 Series Arbitrary Function Generator is a DDS (Direct Digital Synthesized) based signal generato.It can generate output of Sine, Square (Pulse), Ramp (Triangle), Noise and Arbitrary waveforms. It provides 20M Sa/s sampling rate, 10 bit vertical resolution and 4k point memory .Also it can generate 0.1Hz resolution of Sine, Square and Triangle waveforms and the 1% ~ 99% adjustable duty cycle of Square (Pulse) waveform

The output of the function generator was connected to Oscilliscope