Week 6

This page presents the assignments for week 6 of Fab Academy 2020: “Electronics Design”.

To do list:

Group

use the test equipment in your lab to observe the operation of a microcontroller circuit board

Individual

redraw an echo hello-world board,
add (at least) a button and LED (with current-limiting resistor),
check the design rules, make it, and test it,
extra credit: simulate its operation

Week 6 files:

RedrawHelloBoard.kicad_pcb (own work)

RedrawHelloBoard.pro (own work)

RedrawHelloBoard.sch (own work)

Week 6 "hero shot":

Figure 0: ATtiny45 hello-world board redrawn

Individual assignments

Redraw an hello-world board

Using Eagle software

I create a new project in Eagle.

In the schematic file I used the "place symbol" tool add the components needed to the drawing board.

After adding all components, I used the "wire tool" to connect component.

I checked the LED datasheat and use a website to calculate the appropriate value to use for its resistor.

Select ATtiny component from library

Select switch component from library

Check the microcontroller documentation

Board schematic

LED resistor calculator website

From the schematic file, Eagle generated the components (with real size) on the board, but not optimaly placed.

I tryed several combination for components wiring and positioning.

Then I generated a black and white picture.

Finaly I inverted the black and white to get a picture ready for engraving on the laser cutter.

Final schematic

PCB components before positioning

PCB components after positioning and wiring

Generated black and white picture with Eagle

Inverted black and white picture for laser cutter

Make it

Laser cutter

I used one job on the laser cutter to engrave the copper with the layout produced in Eagle.

I used a beeping oscilloscope to check that the trace have been correctly made before cutting the fiberglass.

I then used 20 simple jobs to cut trough the fiberglass of the board.

Setting up fiber laser

Copper engraving

Test trace with beeping oscilloscope

Fiberglass cutting

Board after alcool cleaning

Soldering

I used the microscope to search for copper hairs.

I used beeping oscilloscope for more testing of the traces.

I then glued all needed components on a "to solder list" paper.

I soldered each component and then make beeping oscilloscope test.

Search for copper hairs

Create a "to solder list"

Soldering set up

Soldering components

Board after soldering

Test it

Programming the board

I used ATMEL Studio and ATMEL ICE programmer to program the board.

I checked for online documentation of ATtiny45.

I first programmed the board to wait 1 second before turning on or off the LED.

Then I programmed it to turn on the LED

Board and programmer