555 Project part 2

From design to PCB

This year with students back in the classroom it was time to resume the development process. I was able to use a professional development day in Term 2 to finally get to grips with KiCad. I had already looked at a tutorial so using that as a reference I started the process to turn this circuit into a finished PCB that I could use in classes.

Eeschema editor

Following the steps in the KiCad tutorial I was able to create the circuit, then export this to a board design, choosing the appropriate footprints for components. Next step was to do the layout and connect up the tracks.

Finished PCB layout in KiCad

KiCad has a very neat 3D viewer which means you can view a finished board before it even gets produced.

The 3D viewer even populates the board with components

Previously I had ordered some PCBs from others’ designs from PCBWay as a test. From KiCad I was able to export my board layers as Gerber files. PCBWay has a quick feature where you just upload the Gerber files and it does all of the configuration. Their prototype rate means that you can get 10 boards made for just USD$5, but unfortunately the shipping costs rather more. Nevertheless, the service is incredibly quick, from submitting the order on Wednesday to receiving it on Monday morning, from China to Australia. The unit cost will come down when I order larger numbers for production.

10 + 1 for free!

When the boards arrived, 5 minutes work with the soldering iron and a finished product.


555 project part 1

Two years ago I had my students prototyping a simple 555 based LED flasher circuit on breadboards.

Prototype on mini breadboard

The next step involved transferring this to strip board so they could make a permanent circuit to take home. This part of the process proved troublesome as Veroboard is difficult to work with due to the close spacing of tracks, and the inability of students to follow placement instructions precisely.

In 2020 we started the year, but then COVID-19 intervened and students did not attend school, so did not build physical projects or do soldering.