Tinkercad + Eagle + Laser Head : first steps

A new tool to design PCB from sketches is Tinker Cad Circuits.

This software is a free and easy way to design PCB and emulate them. Together with Autodesk Eagle (free 30 days trial is available on Autodesk website) and FABtotum’s Laser Head it allows to design PCB easily.
Tinker Cad allows to export Eagle’s compatible sketches. Eagle is one of the most common softare used to for PCB making.

This step-by-step guide will show you how to have all the needed files from your sketch and how to convert them in order to correctly use them with FABtotum’s Laser App, the online software you received bundled with your Laser Head.
First of all, create an account on Tinker Cad circuits. Once ready, you can start realizing your sketch, by selecting your bread-board and placing all components as you can see in the sample image. In our example we will realize a simple voltage regulator (or AVR) with a LED output.

Once all components have been placed, you need to connect them with conductive wires. You should get something similar to the photo you can see next here. When all parts are correctly linked you can emulate the circuit by clicking on “Start Simulation” or clicking su “Export” – as for our example – to create the PCB. The file will be saved as .brd.

To design PCB from the saved file, open Autodesk Eagle and open the Tinker Cad Circuits downloaded file, following the path “File -> Open -> Board.

Creating the Layout on Autodesk Eagle

  • Open Autodesk Eagle

  • Open the file

    To open the *.brd file, click on “File -> Open -> Board:

  • Editing

    Once done, a new window will pop up: this will allow you to design a PCB with components all set to realize the final layout.

  • Proceed by placing all components and setting the PCB’s dimentions according to your design. See the image as an example.

  • Routing

    You then need to draw the tracks: you can do this manually  or alternatively you can use the “autorouting” function (for all details please refer to Autodesk Eagle’s guide). When all tracks are ready, you should get something similar to this.

  • Exporting

    Export the layout to be able to laser engrave with your FABtotum Core: click on the “ULP” icon to open the following pop up window. Select “cam2image.ulp”

  • Select “layout2.cam” from next screen.

  • Output

    On next screen, settings should be like: (FileType = .bmp, flag on Monochrome, Resolution DPI = 600).

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Post-processing and Preparation

  • Post-processing

    Software will get you two files: we will use only the layout that contains the tracks. These files will be useful to create the necessary codes.

  • For this example we will use Gimp.
    Open the tracks layout directly from the software.

  • Select the edge of the circuit board, right click with your mouse and select “cut the selected area”. This allows to make sure the dimensions of digital and phisical PCB are the same.

  • This will be your final result (the tracks)

  • Final circuit board will have all components on a side while tracks and pads will be on the other one. Therefore, we’ll need to use the “Mirror” Gimp function in order to rotate the image properly.

  • Exporting

    Next step is to export the image with a .jpeg extention.

  • Clicking on “export” you will generate the file, ready to be uploaded on FABtotum’s Laser App and finally on FABUI.

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Post-processing and Preparation

  • Next step will be the upload of the .jpeg image on the Laser App online that will generate the file g-code for the engraving with Laser Head. Check the available guide to see further examples of uploads.

  • Once the image has been uploaded it is essential to fill the box “width” with the final width of the PCB. In our example it will be 46.66.

  • This dimension is measured using Autodesk Eagle and must be rewritten carefully: this is essential to avoid compatibility issues between pads and will make sure final prototype is correct.

  • PCB etching

    Once you have the g-code, you need to upload on FABtotum’s Project Manager, the photosensitive board must be placed on the Milling side of the Hybrid Bed and Laser Head tip must be 2mm away from the board. Etching process needs to have the darkest ambient available to gain precision. Less light, more quality.

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Start the job with Laser Head and FABtotum

You’ll need to use a different application for the design of the PCB. Our advice is to use a proper guide, even if there won’t be the same example, so tha thte engraving task can be done step by step.

Please refer to that guide for detailed instructions and further information.

Continues: Setting the Laser Head and engraving

Continue: PCB etching