Week 6: Electronics Design

Tasks for  the week:

  • Redraw the echo hello-world board
  • Add (at least) a button and LED (with current-limiting resistor)
  • Check the design rules, make it, and test it

Task:01

Redrawing the echo hello-world board

 

This week the task is to redraw the echo hello-world board using EAGLE.

So my first step would be to understand working in EAGLE to redraw the echo-hello board in it.

Step:01

Working with EAGLE

I found Eagle easy to understand as it allows to make a schematic diagram which is simple to understand. So I decided to continue my electronics design with eagle. Below is a brief introduction of Eagle. Student version can be downloaded from this link.

EAGLE:

"EAGLE is a scriptable electronic design automation application with schematic capture, printed circuit board layout, auto-router and computer-aided manufacturing features. EAGLE stands for Easily Applicable Graphical Layout Editor (German: Einfach Anzuwendender Grafischer Layout-Editor) and is developed by CadSoft Computer GmbH. Cadsoft Computer GmbH was acquired by Autodesk Inc. in 2016.

 

Popular DIY electronics site SparkFun uses EAGLE, and releases the EAGLE files for boards designed in-house. Other notable users include Adafruit, Arduino and Dangerous Prototypes."- wikipedia

 

Making a Schematic in EAGLE:

To start with one needs to know, the components required for the circuit. For Echo Hello board, I referred to the circuit given on the site. I started by understanding the connections between the components.

Next, was to add the components from the add icon from the toolbar on the left side of the screen. But before adding, I downloaded the Fab library for components. The library can be downloaded from here.

Next, I added labels to connect the pins of the Attiny to the respective components.

The above image shows the schematic for my board. Next, I checked it by clicking on the ERC button. It showed No errors. Hence, I proceeded to the board diagram by clicking on the 'BRD' tab in the task bar above.

The above window opened after clicking on the board tab. Now, I arranged it such that I saw less yellow tangles.

Now, before routing,I  made changes in the net classes to have trace width and clearance according to the Fab design rules for the circuit.

 

Trace width: 0.32mm

Clearance: 0.4mm

 

Note: Clearance less than 0.4 mm wont get milled, as the diameter of the 1/64 milling bit is 0.4 mm

Next, I clicked on 'Tools' from taskbar and clicked on 'Autorouter' option from the drop down menu. That led me to the Autorouter Main Setup where I only selected 'Top' direction for the routes since I didnt want it to be a Double sided circuit. Next, I selected 'High' effort and clicked on 'continue' to proceed.

 

Next, I selected the route that showed '100% OPTIMISED' that meant that all my components were connected and no trace was left unconnected.

Checking with the Design Rules:

For this, I clicked at the 'DRC' tab from the toolbar on the left side. Next, clicked on 'load' and opened 'Fab.dru'.

Now, I clicked on 'Check' to see if my board was correct.

It showed me few errors of overlap on the component path, which was not an issue since, the overlap on the component was not an issue , Hence I apporved those.

Next, to export png, I turned off all layers except the top and dimension. Then, from the file menu, I clicked on 'export' option to export it as a monochrome png.

Process for Milling the board- Week 4

The png files for theis week can be accessed here.

The eagle files for this week can be acessed here.

The above images are the png for my Echo Hello board.

Below are the parameters that I chose for milling the board:

Images showing the milling  process and stuffed board:

Hero shot of the Echo Hello board

Board Testing:

To test if the board was functional or not, I connected it to Arduino UNO using the MISO, MOSI, SCK, RST, VCC &GND pins of my board. Since power was supplied to the board the led lighted up. Below is an image of me holding the board, when the LED lighted up successfully by getting power. Now, I could move forward with programming the board.

Programming the board: Week 8