Designing an Arduino R4 Support Plate in Freecad

Following on from my previous post where I started to design a support plate for an Arduino Form Factor FPGA Development board I have decided to make one for an Arduino R4.  This is because I have one and because learning Freecad and sharing my methods are good for me and hopefully of some use to those who read my blog posts😎

So lets get a look at the Arduino R4 and it's dimensions:

I found this drawing from the Arduino R4 manual which is here: Arduino R4 Manual.  There is an image of the board below in case it is needed.

I also helpfully found a Freecad model for the development board which will help considerably as it allows one to build an assembly model and check everything fits properly:

https://www.printables.com/model/1054095-arduino-uno-r4-wifi-cad-model-corrected/files

So to begin with we can perform the same steps as I did in the previous post:

1. Load up Freecad and start a new project in the part design workbench:

I chose to call mine ArduinoR4_Support but you may choose something else.  I would suggest you save your files in an appropriate folder too.

2. Create a new Body and Start a new Sketch on the XY Plane:

3. Draw a centred rectangle by clicking on the 'Centred Rectangle' Tool measuring 82 mm x 75.2 mm.

4. Create some rounded corners -  Click on the create fillet tool and select each horizontal and vertical line near the corner.  Do not worry about accuracy:

5. Hold down the CTRL key and select all four fillets and then click on the 'Constrain Equal' tool or press 'E':

6. Set a 4 mm dimension to the fillets by clicking on a fillet and clicking of the smart dimension tool:

7. Exit the Sketch and save the file - always a good idea.

8. Pad out the shape to 3 mm:

9. Create another sketch on the XY Plane:

10. Exit the sketch back to the Part Design Workbench.  

11. Attach the sketch just created to the top of the plate created by selecting the top face:

12. Return to the sketch just created and draw another centred rectangle (dimensions: 75.2 mm x 59.94 mm)

13. Add some fillets as before with radius of 5.84 mm, make sure to set the fillets to be of equal constraint:

14. Using the Arduino dimensions about trace out the shape of the arduino.  This is particularly difficult.  Start with a centre rectangle then remove the right side line and freehand sketch the bevelled edges and finally add the corner fillets:

 

 

15. Exit the sketch and extrude the shape out by 3 mm using the pad tool:

 

 

16.   Now is another good time to save our work...

17.   Click on the inner plane of the shape and attach a new sketch - Its time to add the support pegs for the arduino.  Roughly place 4x circles in the appropriate positions and set them all to equal size and then dimension one them to be 2.8 mm diameter.

  

18.  Next constrain the circuit positions as shown in the image below:

 

 

19. Exit the sketch and pad the circles to 3 mm height:

 

20. Create another new sketch on the top of the ring plane ready to add some cut outs for the USB and power connector:

  

21.  Place some rectangles roughly were the DC power jack and USB connector are present:

 

 

 

22. Constrain the size and position of the rectangles as shown below:

 

 

 

 23. Bevel the edges of the rectangles with a 45 degree angle to allow the connectors some room for insertion and disconnection: