Simple KiCad example; Sch, Brd, Sim, 3D

I remember starting out wishing I had an example KiCad project just to show me how KiCad (pronouced Key-Cad [French developer pronunciation]) worked for inspiration for further exploration:
555.zip (2.0 MB) Most examples I found weren’t complete enough to help with full project comprehension.

This package can be opened in KiCad with File->Open Project… or just clicking on the 555.kicad_pro file in file explorer. Things you can do immediately;

  • Open 555.kicad_sch

  • Click on U1, the 555 timer IC and press ‘D’ on your keyboard. You should see the 555 datasheet

  • Simulate the 555 Timer using NGSPICE

  • My intent with simulation is to show functional output using a circuit with passive, parametric, and functional design parts/blocks. The circuit is simulated at 5V and jumps to 15V power input to see how the 555 might behave with a 3x voltage change.

  • Is Q1 really needed? Try modifying the circuit by removing Q1 and wiring the Emitter Q1.1 to Output U1.3 and re-simulate after removing Q1. This will show U1 output with capacitive charge/discharge characteristics caused by slightly higher 555 output loading.

  • Make “Smart PDF” documentation using the File->Plot… output

  • Click on U1 or Q1 (in the smart PDF) to see schematic part information

  • Run Electrical Rules checker and try to fix the issues

  • Open 555.kicad_pcb

  • See what the board looks like in 3D by pressing [ALT-3]

  • Spin the board around to see how it looks in 3D

  • Export the board image to STEP format which can be imported to your favorite mechanical CAD design tool; FreeCAD, SolidWorks, etc. for modeling

  • Save the board in JPEG format for documentation in Word or LibreOffice Writer

  • Export the board to STL and 3D print it

  • Pretend you’re going to send the board out by exporting to ODB++ or IPC-2581 which can be submitted to your favorite PCB vendor for a bare PCB and/or assembly quote (if you actually do this, send me one! [though-hole or SMD])

  • Fix the mounting holes so they are connected to Ground

  • Redo the board with surface mount parts (use 0805 or larger parts if you plan to assemble it yourself by hand)

  • Get an idea how much the parts might cost with KiCost (open 555.xlsx) to see example output

  • Look at a manufacturing assembly view of the board by opening 555-ibom.html in your browser (made with “Interactive Html Bom” plugin)

The first time I posted parts of this was 3D Formats - 3D Printing fun with KiCAD/FreeCAD + EE101 type KiCAD intro when I wanted to experiment with modeling for parametric case design. I started with a 3D print.

A simple circuit like this shows project layout at a file level, and provides a working simple example of how to use KiCad though several design and production stages.

3 Likes

These are good to have. And a (Youtube) video of how it is done.

But a colleague once said that a every board should have a LED. A LED on the output immediately tells if it is working. A blinking LED is best, it tells that it is working, it is not working, it is working, it is not working…(An old Finnish joke of how to test car’s turning indicators)

1 Like

Good suggestion!

And it sounds like an opportunity to try the new “variant” feature in KiCad.