Build Instructions

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• 1

  Step 1

  Selecting Hardware

  Case
  Searching online, I found the "Mini Macintosh", an accessory from the American Girl doll catalog that was released in 1996. This toy version originally had a 3.25" monochrome LCD display that showed static images as seen in this YouTube video. I thought it'd be perfect, so I bought one on eBay.

  
  Computing Module

  Once I got it in my hands, I realized that a Raspberry Pi wouldn't fit in the case unless I started de-soldering connectors, and even then it'd be a challenge. Fortunately, around this time HardKernel released their ODROID-W computing module, which is a South Korean clone of the Raspberry Pi. It got some hate from the internet, but it's still an impressive bit of engineering so I ordered one immediately. (They've apparently been discontinued since then.)
  
  Display
  The screen comes from a Chinese automotive rearview display. I had previously tried a TFT display, but the drivers for this particular one aren't well-written so it flogs the CPU at 100% whenever it's in use.
  
  Power
  Since the screen runs best at 12V but the ODROID-W only needs 5V, I bought this DC/DC step-down converter. It takes anything between 12-24V as input, and outputs 5V at the other end.
  
  Peripherals
  I also included a USB Hub, USB Wi-Fi adapter, and a wireless keyboard/trackpad.

• 2

  Step 2

  Preparing the Case

  I disassembled the case and found that it consisted of three pieces: a "lower" base with the battery compartment, the "upper" shell with power switch and speaker, and the front panel with screen.

  In the lower base, I slightly widened a hole where the original mouse wire entered and inserted a combination power and RCA cable. The cable was originally for a microphone, so all I had to do was cut it apart and spray it with a can of gray vinyl dye. The RCA connector will be wired to the secondary input on the display, so I can connect other composite devices as inputs to the Mac's screen.

  Shown above: The lower base with power/RCA cable.

  In the upper shell, I soldered JST connectors onto the power switch. The female plug is "input", while the male connector is "output", with the toggle switch operating as a simple open/close on the positive lead. There's a mono speaker (8-Ohm, 1-Watt) mounted in the top as well. I originally tried using an audio amp from Sparkfun, but the quality wasn't very good so I've removed it until I figure out an alternative. In the meantime, the wires are bundled together and secured with kapton tape.

  Shown above: The upper shell with power switch and speaker.
  Shown below: The lower base and upper shell shown assembled.

• 3

  Step 3

  Mounting the Internals

  To avoid damaging the casing and to allow future expansion, I made an internal frame that would house all of the other components independently. I modeled it in Sketchup and then laser-cut the design out of 1/8" acrylic.

  Shown above: The internal mounting frame, as designed.
  Shown below: The internal mounting frame, finished.

  The walls of the frame are held together with tape, which seems to work well enough for stability. The ODROID-W and USB hub are mounted to the sides using screws and threaded inserts. The power converter is mounted to the floor in the same manner. The audio amp was mounted to the top using zip-ties, but I removed it prior to taking these photos. The excess 5V power wires are secured against the step-down converter with more kapton tape for future use.

  Shown above: Alternate view from the rear, as designed.
  Shown below: Alternate view from the rear, finished.

  Shown above: The frame is inserted into the assembled lower base and upper shell.
  

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