Computers

Here you will find details of the computers I have owned and projects I have used them for.


Sinclair ZX

IMG_9365

I credit Sir Clive Sinclair with bringing the Home Computer to the masses. The first two computers were even offered as kits to reduce the price to the end user and to offer the opportunity to build your own computer.

A friend lent me the first computer I ever used. A Sinclair ZX80 with a graphics conversion so that the screen did not flicker each time the ZX80 had to think about something. It amazed me that this was supplied as a kit because there were a lot of microchips supporting the processor.

 

After the ZX80 I purchased my first computer, a ZX81. I no longer have this version as I did a fair amount of customisation and it eventually disappeared. I have another example purchased from eBay, which I replaced the keyboard, again purchased from eBay. It is now a good working example with 16K RAM pack.


Later I decided to add a Sinclair Spectrum to my collection and bought a boxed example of a 48K spectrum with the rubber keys. The trouble is having used a BBC Micro extensively the Spectrum does not provide anything special. Yes it is in a small package but it means the keyboard is not as easy to use as either the Dragon or the BBC.

Dragon 32

Dragon32s
IMG_4056

When I had started work I bought a Dragon 32. It cost me £129 from Dixons. Again I modified this and housed it in a separate box. After many years in the shed and never being finished, I bought a non-working example from eBay and replaced the motherboard and PSU with the ones I had originally and now have a great working example as shown in the picture. Together with the Dragon is the Dragons Claw which provides a BBC Micro compatible user port for the Dragon. It is a really great piece of kit for interfacing with gadgets.

Some of the projects I made for the Dragon were a speech synthesis module that would use allophones to speak the text you gave it. Always sounded like a computer speaking but this was a long time before you could digitally record sound on a PC. I also made my own user port using the 6821 Interface Adaptor to connect an automatic model railway. I never completed this project but I learnt a lot about interfacing electronics and logic addressing.

There is an emulator called xroar available for Windows and Mac from this URL: http://www.6809.org.uk/xroar/


Atari ST

After the Dragon I moved on to an Atari STFM. I bought this from a computer company within a much larger store in Oxford Street. It cost around £320 and left me very confused originally as, unlike all the computers I had before, the computer did nothing without booting from a floppy disk. However, I persevered with it and found it to be one of the best computers I owned. Originally it had 512K of RAM and I bought a set of memory chips, sockets and capacitors and soldered an upgrade of another 512K. I wrote many programs for this computer including a database and label printing software.

I was so impressed with this computer I upgraded to an Atari Mega 4 STE, which I still have. It has a built in 40MB Hard Disk drive and it has many serial ports, including MIDI.

BBC Micro

IMG_0153e

Acorn beat Sinclair to provide a computer the BBC could use in education programs about computers. The BBC Micro was a much later addition to my collection but I used one regularly as I spent many an evening round a school friend’s house playing Elite. It is truly the best of a generation. The ability to expand it and program it was second to none and suppliers provided all manner of equipment to use with it. I even used one at college for CAD work. It included a second processor and mouse.

The model B I have now was given to me by a friend. It had been upgraded somewhat with extra ROM and RAM boards. I have returned it to a standard model B but retained the DFS to allow the use of the two 5 ¼” floppy disks.

I recently purchased a SD Card disk emulator to allow the quick saving of files to SD card instead of the bulky 5 ¼” disk drives. However, while testing the drive the BBC went bang!! It was a typical power supply problem caused by age. There is a high voltage capacitor on the input side of the power supply and these break down over time. The old ones had paper insulators, which catch fire when the capacitor breaks down causing a lot of smoke. I bought a replacement from Maplin and after changing it for the new one the BBC sprang back to life.

Raspberry Pi

IMG_3205


In 2012 I heard about the Raspberry Pi. On July 20th, I ordered one from RS Components and saw that there was a long wating list. At the end of September my order had been put back past November and I saw Maplin were now selling them. Within two days I had one.

I wanted one to use in my electronic projects. First of all I wanted a low power computer to use as a webcam and to update my website from my weather station. I purchased a Raspberry Pi camera and have it set up as a webcam. I will be adding the weather station update in the coming months.

I recently bought a new 512MB version and another camera to use for portable time lapse photography projects.

IMG_3206

You can tell the board from the Made in the UK label and the different board layout. The GPIO connections are slightly different from the original board.

Pictured below is my new Raspberry Pi B+ which includes 2 more USB and an extended GPIO. I bought this from RS Components 3 days after launch (14th July 2014).

1DX_7905

Finally after waiting a while I now have a Raspberry Pi 2 which is a Model B+ with an uprated specification:

1DX_7904

The newest addition to my collection is a Raspberry Pi 3:

5DS_2530


My Collection of Raspberry Pi’s now consists of:

  • 1 x Original 256MB Model B
  • 2 x 512MB UK Model B
  • 1 x 512MB Model B+
  • 1 x 1GB Raspberry Pi 2 Model B
  • 1 x 1GB Raspberry Pi 3 Model B
  • 2 x Raspberry Pi Zero
  • 2 x Cameras
  • 1 x PiFace Digital
  • 1 x Astro Pi

Projects:

  • Webcam (on this site)
  • Garden Camera complete with night vision (under development)


© Perry Andrews 2017