You have reached the homepage for Grant Searle's bits and bobs. Please feel free to browse!

Hi. This page links to my other electronics and computer pages.
A bit of background... I live in the UK (Wales, actually). I was born in 1966 and had my first soldering iron when I was eight. After many years of burnt fingers I am still going strong with electronics. From mid 1975 until late 80s I subscribed to Everyday Electronics - still have them all in a big stack, and have also managed to get hold of the ones from issue 1 to when I started. Also bought Practical Wireless, Popular Electronics, Hobby Electronics etc, to name a few. My interest in computers started in about 1977, so I was very active with the home computers at the start of the 80's and started with a Dragon 32 then went on to the wonderful BBC Micro. Over recent years I have turned to collecting some of the old computers, electronics kits and TV games, and I have rebuilt some of the computers (see below).

Have fun browsing, I've spent a lot of time on these pages and hope they are of use to you.

Regards, Grant.


Index
Scroll down, or jump down from here...
My CP/M design | My simple 6809 design | My simple Z80 design | My simple 6502 design | My simple video/kb interface | Low cost FPGA projects | Space Invaders | My electronics kits | My pong TV games | ZX80 | Jupiter Ace | UK101 | My computers | Pong | My new 70s TV game | PW Tele Tennis | Super Breakout | Other Stuff


For news and updates, follow me on Twitter:
Follow @zx80nut

CP/M - my own design
A fully functional Z80 CP/M machine using only 9 chips

Click here to see my home-designed CP/M machine built on breadboard. I designed the circuit and wrote the BIOS and much of the monitor myself.


Simple 6809 - my own design
A complete 6809 computer on 6 chips

In the same style as the Z80 computer below - can't get simpler than this!
I designed this to be as simple as possible while still allowing it to be expanded.

Click on the picture to go there.


Simple Z80 - my own design
A complete Z80 computer on 7 chips

In the same style as the 6809 computer above - can't get simpler than this!
I designed this to be as simple as possible while still allowing it to be expanded.

Click on the picture to go there.


Simple 6502 - my own design
A complete 6502 computer on 7 chips

In the same style as the 6809 and Z80 computer above - can't get simpler than this!
I designed this to be as simple as possible while still allowing it to be expanded.

Click on the picture to go there.


Simple Video and Keyboard interface
Text/graphics PAL or NTSC video and a PS/2 keyboard interface.

Ideal for any computer (such as my designs) which has a serial port.

Click HERE to see it.


Low-cost FPGA projects

l have created several recreations of computers on a very low cost FPGA board. Some are published here...

A complete UK101 with internal 4K RAM Multi-option design-your-own computer  

...ideal to get you started with FPGA

 


 

Space Invaders

My redesigned circuit build using a Z80 with the ORIGINAL arcade ROM code so is fully faithful to the original, and can be used as a replacement in a cabinet if needed. You can see it running in the picture at the top of the page. The sound circuit is the same and the shifter circuit is very similar to the original, but the rest of it is totally redesigned from the basics to allow the use of a Z80 processor instead of the 8080. Fully shared memory with the CPU and graphics with efficient bus contention arbitration. The chip count, although high, is significantly lower than the original. Click HERE to see it.


My electronics kit collection


My first kit, when I was eight, was the "Science Fun Experiments In Electronics" by Logix Kosmos. The first circuit that I ever built was on that system and I've kept going ever since. I don't have much of that kit left, unfortunately.

Here is my unintentional collection of electronic kits from the 60's, 70's and 80's.


My TV game ("pong") collection


Back in Christmas 1976, my present was a Videomaster Superscore black and white unit with a pistol. Unfortunately it only lasted a few days before it failed, so I then got (and still have) a Grandstand 3000 colour one instead. Over the last few years I have been collecting some more machines from this era.

Here is my collection.


My new 70's TV game design


A faithful (as possible) recreation of the classic 70's TV games done on a modern microcontroller and very few other parts. Based on the Atmel ATMEGA328 processor using Arduino code. Can be build on an Arduino board or using a stand-alone microcontroller (Arduino hardware/software not needed).

Click HERE to see it


Home-built micros

Build your own
I have produced chip labels for all projects on my pages. Please go HERE to get them.

I have built a few of the home micros using the schematics. To see the results, please visit the following pages:

ZX80 page

Jupiter Ace page

MicroUK101 page


My machines

Over the years I've been collecting the micros which were popular, mainly in the 80's. I currently have about 70 different computers, plus several "spares". Here is a selection of what I've got. Click on the picture for details:

My machine collection


Pong
Arcade Pong

I decided to build an arcade Pong machine using the original Atari schematics and a large number of chips in my spares box. I was pleased that it worked first time. If you want to see the results of my weeks work, please go to my Pong pictures here. Also included there is a build of a magazine-published version of Pong. This differs from the arcade version because it is an analogue design, popular with the very first home consoles, instead of the digital version used in the arcade Pong.

 

Practical Wireless "Tele-Tennis"

First published in 1974. I wanted to build this for a long time, so finally in 2008 I did so. Click here to see the results. Included on this page are scans of the complete construction articles, re-published with kind permission from the copyright holder, PW Publishing Limited.

Super Breakout
The arcade version

I won an old Arcade Super Breakout board from eBay. It was a major restoration, but here is how I did it.

Other stuff
The Ladybird Radio

Many (!) years ago I built a great medium wave radio from a Ladybird book. I still have it, and here are photos of it,

 

MK14

Anyone interested in the MK14 computer may want a copy of the original SCMP datasheets which I've scanned:
SCMP datsheet scans

 

Sinclair Spectrum clone

I had been following, with great interest, Chris Smith's "Harelquin" Spectrum Clone here: http://www.zxdesign.info/thebeginning.shtml
I was so impressed that I HAD to have a go myself. I am very pleased that I managed to get the design working.
You can see my version (some differences to Chris's design to simplify the Sync circuitry) here.
(not much there, yet, but please look at Chris's log pages for some excellently detailed information)


Contact me
My contact address is currently:
    
I will always try to get back to you, but I don't always get the time, so please be patient. No requests for buying anything off me though, please

Please note... if I start getting spam on this address then I will drop this address and use a new one.
(If you have contacted me and have not had a reply, check back on this page to see if it has changed)