Electronics Design

Task

I have this week worked with electronics design and completed the following:

• Redrawn the Echo Hello-World board.
• Used our test equipment to observe the operation of the board.

Electronic Design Tutorial

I followed this tutorial created by Anna Kaziunas France.

Electronics Design Process

The list below summarizes the steps in the Electronics Design Process:

• Install EAGLE and add the 'fab.lbr' library.
• Add and connect component to the Schematic (.sch).
• Use the Electrical Rules Check (ERC) to verify the design.
• Switch to Board Layout (.brd), arrange components and route the traces (see note).
  
• Export the board design (both traces and dimensions) as monochrome image (.png).
• If necessary crop the exported image and then add 10 px white border.
• Use FabModules to create a milling path and mill the board.
  

Note:
The width of a 1/64' milling tool is (1 inch = 25,4 mm, 1/64 inch = 25,4/64 mm = 0,397 mm ≈) 0,4 mm. This means that FabModules will create a milling path that does not mill away black areas with a width of less than .4 mm.

I made a redrawing of the Echo Hello-World board with departure in the example given in the tutorial.

I tried to make the board smaller than the one presented in the example, and made a range of changes to the original desing including:

• Inline placement of LED and resistor.
• Moved FTDI header and button closer to the Attiny.
• Adding angled routes.

Eventhough I followed instructions from the Electrical Rules Check I ended up with a board file with less than .4 mm between the routes.

I discovered the error (highlighted below) when checking my board with the multimeter (after having soldered all components). I traced the error back to creation of the milling path in FabModules. I decided to try to reset the tool diameter (from .4 mm) to .3 mm, which resulted in a 'more correct path'.

I soldered the components to the board (see image at the top/buttom of this page). I then startet checking the board using a multimeter to check for:

• Conduction between soldering points when ment to be.
• No conduction (short circuits) when no ment to be.
• Correct functioning of resistors and LED.

Design Files

• Echo Hello-World example board (.zip, 61kb)
• Traces for Echo Hello-World board (.png, 27kb)
• Outline for Echo Hello-World board (.png, 11kb)