Miniature MZ-80K

Making a miniature of MZ-80K as “Real Computer”

It actually runs!

The 1/5 scale model of MZ-80K is my artwork in 1981, when I was a high school student.
It was mainly built by plastic plate of 1.5mm thickness, because its design was mostly square-shaped.
It took effort to trace accurate shape, paint for good appearance.
Especially it was too laborsome to paint the each key-top by hand, I cannot do it again now, haha.

Raspberry Pi Zero was released last year, Pi Zero W follows this year.
And then, HAL Laboratory announced to produce “PasocomMini” this autumn.
That is a retro-style computer running Smile-BASIC,  reproduces the shape of MZ-80C in 1/4 scale.
Well, all the stuffs are ready, let’s make one of mine!
Now I want to know how the technology has advanced through these decades.

<Concept>

  • Watching as a precise miniature. Playing as a real computer.
  • Looking back to 1978, the year of MZ-80K was born, from 2017’s eyes.

The reference for Sharp MZ-80K (Wikipedia)

<Function>

  • Main board : Raspberry Pi Zero W (1Ghz clock, 512MB RAM)
  • Display unit : 1.5inch TFT, NTSC/PAL input

  • Sound : Stereo audio output from Raspberry Pi’s PWM via low pass filter
  • Network : Wifi and Bluetooth on board
  • OS : Raspbian (Standard GUI desktop environment of Raspberry Pi)
  • Input : Not available itself. Use with external devices from USB/Bluetooth or VNC viewer from other PC/Smartphone.

  • Battery : 2000mAh LiPo battery. Running time has not checked, maybe 2 hours or more.

<Internal Connection>

<Technical Topics>

  • All of the terminal is accessible for cabled connection, though it normally runs wireless.
  • Charging port is settled backside of the body. Charging indicator is lit by internal LED through an optical fiber.
  • Power indicator is lit by internal board through an optical fiber.
  • Power switch is set at left side of under-body.
  • The top body can be fully opened by pivoting newly added hinge.
    The work could not be done in 1981 due to lack of my skill, I use brass pipe and 3D-printed hinge parts in this challenge.
  • Wiring with connectors and composition of parts are designed to meet the demand of maintenance-purpose..such as replacing battery.
  • Cooling is one of major matter in this project. I took care of it much.
    • A small copper heatsink was attached to CPU chip.
    • Large copper plate was attached to radiate the heat of CPU board. A heat transfer material is used to joint the board and plate through bottom’s hole.

  • Outer scheme has no change this time, except fixing a small gap at backside of the body.

<How She Runs>

  • The screen is awfully small, lol.. It is very hard to accomplish usual work with the machine itself..
    Off course, external HDMI monitor or VNC connection will open the door.

  • There is remarkable heating of bottom copper plate after continuous high CPU usage.
    That indicates the effect of cooling stuff, also reminds me of heating problems in this era.

<Conclusion>

  • Actually it is far more convenient to use a smartphone than using this gadget machine.
    But it is like a vintage machine awoke from long slept past. Lovely.
  • The job of 2017 and 1981 were both done by myself. But it is like a collaboration work beyond long time.
    I have strange feeling about that.
  • Raspberry Pi  Zero W is very wonderful platform, ideal for the project such as this.
    You’d better try it, good luck !
  • Pictures of the making process are stored at below Google Photo Album
     →Link to Google Photo Album