Arduino - chipKIT enclosure, fancy

Last crawled date: 1 year, 11 months ago

Note: default "rendering" is an actual picture of 3D printed part in production.

This is the 4th Arduino housing I have designed. The top shield is intended to be the Adafruit 1.8" TFT I have in the library. Below it is an Adafruit prototype shield and a Seeedstudio Mega. Notice the support cage in the middle layer, it is to hold the bottom of the Arduino "stack" up in place. Without it, any inputs to the power connector, USB connector, or other connectors to the other shields could pull them down and away from the top shield.

The cutouts in the bottom layer are to add rigidity to the 3D printed model. Without those gothic looking column indents, the 0.125" front wall was very flexible and induced layer adhesion problems during the ABS 3D print. This version is very rigid and did not "split" during the print.

The top shield, the Adafruit 1.8" TFT with joystick and SD card, bolts to the lid with M3 screws. The holes are sized to accept a tap after 3D printing. There are cutouts for the SD card to allow its removal and update as needed when in production. The top lid does bolt into place, but hinges with the 2 pins into the middle layer. This design works well in practical use with the 3D printed ABS.

NOTE: the very top piece, the "lid" has been updated to add more support for the PCB when the screws are tightened. Initial version would allow the PCB to flex, which I found was cause for the TFT to not function properly. Update is its own lone lid_v2.stl file. If you need a different version (STEP, dwg, dxf, etc) please comment and I'll export accordingly. STL loaded because I 3D printed it and tested it.

All bolts besides the top 3 M3 screws are M5 and as 3D printed in ABS are ready to be tapped after the print. My 3D printer shrinks holes slightly, so are sized 0.190" in the drawing. You may need to adjust for your application. Note: I found this hole size would allow the M5 screws to thread into the raw plastic, however, I tested and discovered their strength and "bite" is much more firm if the holes are first tapped!

There is a removable "door" that slides in the middle layer which is trapped by the lid. This door is clumsy in usage, but once the test bench no longer needs updating via the USB connector, will be a more permanent fixture.

Note about the door and middle layer: the power connector to the Seeedstudio Mega protrudes from the housing. This was my design concession to space restraints. This connector did not lend itself to concealment easily! Also note that the Seeed Mega has an unusual layout. It can be seen and purchased here: http://www.seeedstudio.com/depot/seeeduino-mega-p-717.html I rather like this product for offering Mega performance in an undersized "Uno-like" footprint. (Note: this "Goldilocks" Uno might be even better! http://www.freetronics.com/products/goldilocks-arduino-compatible-with-atmega1284p-mcu )

A write up about this project is here: https://forum.sparkfun.com/viewtopic.php?f=14&t=36254

Update: changed the MCU to chipKIT platform to quadruple my SRAM from 8K to 32K! More here: http://www.chipkit.org/forum/viewtopic.php?f=18&t=2530