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Wednesday, 25 September 2013

My Revised Second Raspberry Pi Lego Case (pi model a ver1 rev2)


The previous version was demonstrated in the previous blogpost (http://ddurdle.blogspot.ca/2013/09/my-second-raspberry-pi-lego-case-pi.html)

Intention [unchanged]: To be used as a XBMC media player.  Some will include a wifi dongle (for streaming) while others will feature only videos stored locally)

Challenges addressed with the revision:

  • add a power switch (to provide for easy-means of shutting down, powering off and powering on the device)
  • widen the IR window to broaden distance and angle
  • build a safe-guard around the SD card (to protect the SD card slot)
  • re-orient the raspberry pi so the right-side becomes the predominant side (front-side)


Equipment:
Assumptions:
  • No need for the VIDEO port (going to use HDMI)
  • No need for AUDIO jack (going to use HDMI)
  • No need to access camera port, GPIO pins, etc
  • Require a "window" for IR receiver
  • No powered hub required; will be streaming, using SD card/USB key/powered-hard-drive for video watching
Front-side view



Gone is the IR window from the fronts-side.  The IR receiver has been relocated to the right side under a more generous window.  The unit now raises 2/3rds a lego brick size higher on the right side to accommodate the wiring extending from the power switch.


Right-side view:


closeup with switch powered on (blue light)



Added exactly one lego block size out on the right side of the unit, and 2/3rd a lego block size higher.

The IR window is 4 times as large as it was before (was 2x1, now 4x2) and there is 180 degree aperture  as there is an additional 1x2 of the window accessible from the front view of the unit.

The illuminated push button fits perfect with ample space around to prevent the button catching on the case.  The exact size allowed in my design was 4/3rds a lego brick size.  The micro-USB slot is slightly higher, being replaced by the one on the power switch.  The new micro-USB slot fits more flush with the case then the previous one.

The addition of the lego blocks has provided a better safety mechanism around the SD card, as it now sits completely flush with the unit.  The build up of the blocks gives the case more stability as now both the front-side and right-side are two lego blocks in depth in the core areas giving the case more structural integrity.

Notes:  
  • The SD card is nearly impossible to pull out with your fingers (unless your fingers consist of toothpicks) -- both an advantage and disadvantage.  To take the card out, placing a piece of tape on the top of the card would provide you the needed grip to pull the card out.  As a compromise, the lower section of blocks were strategically built in a manner that would allow you to easily pull the bottom section off without dismantling the case or removing unnecessary blocks.  Care just has to be taken when pulling the blocks off.
  • Consideration was given to making a finger gap to allow for my fat fingers to be able to grab the SD card and pull it out, but was decided against as it left a huge unsightly gap and pulling the card out in such a manner would put at risk damaging the SD card slot.

Back-side view:


I had to extend the HDMI opening by one lego block size on the right.  The original design allowed the board inside to shift left or right up to 3 mm, which would accommodate HDMI plugs that have a fat plastic casing (and indeed most of mine have this).  With the new additions to the case, the board inside fits more snug with just a 1mm shifting allowed for temperature contractions/expansion. You end up seeing more of the internals and subject more to dust.

Left-side view:



Only change here is the changing of the window colouring from blue to white to match the right-side.  I had no large windows for the right-side that were in blue tint (at least none that I could easily find).

The picture shows a wifi dongle attached to the USB port.

Notes:  

  • The onboard LEDs colour output is noticeable at this viewing angle (red glow indicates the system is powered on, a slight green flow overtop the red glow indicates data is being accessed).  This level of output was sufficient for the intended deployment...
  • The white window is thicker in material (the blue tinted window was hollow from the inside), so the LEDs are more obscured from view in this case design.  Since the re-positioning of the case now puts the LEDs in the rear, the function of these LEDs becomes less important.  The illuminated light switch replaces most of the need for these LEDs. 
Top view:


A slight incline on one side.  Some may think it makes the case look ugly, but I think it adds to its character.

Notes:  

  • The raspberry pi internals are still not easily accessible from the top.  Unlike some of my other lego cases that feature a door for access, there was no need for easy access in the intended deployment.  With the new incline, the GPIO is even more of a challenge to access,however, the wiring for the IR receiver and power switch are very accessible with just the removal of a single 4x4 pannel.
Action shots:



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