Z88 Tribute Computer

In honour of Sir Clive Sinclair here is my 2023 version of his great Z88. I hope he would approve.

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The Z88 was, nay, still is, a remarkable machine. I've seen it described as the iPad of the 80s.
Although I was using computers long before Sinclair came on the scene, it was his ZX81 kit that got me hooked on building my own hardware.
Of all the machines Sir Clive produced, the Cambridge Z88 found a special place in my heart from the day I first saw a magazine advert for it. After purchasing one and using it for several decades (yes, really), it eventually retired to a quiet box in the attic.
Then in 2022, I was hunting for something and instead found my Z88 again. Waves of nostalgia washed over me!
Anyway, I couldn't help but think "I wish there was a modern version of this classic". But alas, Sir Clive had already passed on. May he rest in peace.
So I grabbed all the common stuff that the trendy kids play with these days and got to mashing stuff together in the hope of producing something respectable.

Adding project details, etc. over time as I reverse engineer my own project! 

Here are some specs of this machine:

  • Customized Desktop / Workspace environment to honour the Z88 UI
  • Built-in Application Suite to provide modern alternatives to the Z88 built-in apps
  • Powered by Raspberry Pi 4 running Raspberry Pi OS
  • Built-in 1920 x 480TFT screen, with custom capacitive-touch overlay
  • Built-in mini physical keyboard with USB controller
  • RAM as per RPi4 specs
  • SD Card storage as per RPi4 specs
  • WiFi as per RPi4 specs
  • Bluetooth as per RPi4 specs
  • Li-ion battery with battery management 
  • USB-C charging
  • Wireless charging
  • Hardware button to Power ON/OFF
  • Hardware button to switch between Low-power usage and Full-power mode
  • Tough ABS portable tablet style case
  • Wireless charging base with ergonomic slope for easy desktop or laptop use
  • Built-in Z88 Emulator (OZvm) with customisations to support hardware for those who want the "Real Experience" ;^)

And, of course, plenty of scope for expansion thanks to the Raspberry Pi 4's remaining unused I/O.

Photos of the internals of the Z88 Tribute

1. Open case. Screen and keyboard (face down) at the top of the photo. Wireless charger and USB-C connector at the bottom.

2. Closer look at the bottom of the case.

In the centre is the wireless charging circuit, which consists of a coil, a controller on a circuit board and an inductive shield in the form of metallised sticky tape. The coil is mounted so that it close to the top of the Z88 Tribute to allow it to be placed on standard commercially available wireless chargers, as well as it's own charger.

To the right of the photo the USB-C socket can be seen. The case wall has to be carefully scraped away until it is thin enough for a USB-C plug to make full contact inside the socket, when mounted and plugged into from the outside.

3. A closer look at the gubbins.

Below we can see the Raspberry Pi 4 on the centre right. Directly behind the RPi4 is a battery management circuit. Both are held in place by a 3D printed holder.

On the centre left is the Li-Ion rechargeable battery, also held in place by a 3D printed holder, plus a couple of cable ties.

Immediately below the RPi4 and battery is the keyboard matrix decoder for the built-in keyboard.

4. Audio and video close-up.

The HDMI to LCD board (which comes with the 1920x480 LCD screen) is removed from it's housing and rotated to the position shown in the photo, to allow connection to the HDMI output from the RPI4. This decision was forced due to the choice of connectors available.

The HDMI to LCD board also supports Multi-Touch Input via a micro-USB connector. Unfortunately, the display unit does not come with a Capacitive Touch Screen Digitizer, so a compatible one was sourced.

Notice above the HDMI board, one of the built-in loudspeakers and to the far left the "SLEEP" button. It's not a true SLEEP button, because the RPi boards do not support low-power sleep modes. Instead, I have configured it to shutdown the display and as many peripherals as possible.

5. Audio and Touch-Screen.

Finally, towards the centre of the photo we can just see the Touch Screen Digitizer board, hidden beneath the flat white cable.

At the top, there is the other loudspeaker and to the far right, the POWER button. The POWER button triggers a clean shutdown of the OS and then the RPi4 itself.

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  • Still here ...

    The Lab Guy03/21/2024 at 16:40 0 comments

    Just adding a log entry, seeing as I haven't updated this project progress for a few weeks.

    There will be more photos and details about assembly steps, software configuration etc. soon.

    I have been somewhat distracted by another retro-computer project that I discovered out-of-the-blue, and I couldn't resist but look into it.

  • Kick-off reverse-engineering and publishing my Z88 Tribute

    The Lab Guy01/30/2024 at 12:51 0 comments

    I built most of this project in 2022, just picking up and dropping off as I could.

    The only real design choice was that the finished article should look and feel as much like the Z88 as I can manage, but use modern hardware, software and communications.

    For those who don't know the Z88, it was clean, simple and fluid to use and ran on four(?) AA cells. Yet, you could run a business with one using only the built-in apps and serial printer, if you wanted to.

    That's a far cry from the heavyweight applications and OSes we have today, with user interfaces that expect extreme graphics and power-hungry hardware.

    So, although I created the project a few days beforehand, today I took some photos (the very first photos I have ever taken of this project BTW!) and have proceeded to upload ed them to the project page.

    Next, I am going to start taking the system apart and photographing and writing up how each subsection was built, configured, connected, etc., extracting the parts list and producing detailed instructions on how to build your own, if you wish.

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  • 1
    Poor workmanship disclaimer ;^)

    I know, I know. In the photos of this project there are scratches on the casing, there appears to be a massive hole that looks as though it was cut with a chainsaw, there is glue all over the place, the 3D printed parts look as though they were made on M.C. Escher's printer. 

    All I can ask is please forgive my poor workmanship. It was the best I could do given my circumstances at the time.

    I will endeavour to highlight alternative methods, materials and/or tools as we cover the worst bits, which should help you to achieve a more refined article.

    Now, onward...

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