Home and Hobbies

On this page: General Comments | Audio Electronics | Computer Hardware | Disco/Stage Lighting | System Software | DIY | Languages | General Computing

Goto top of this pageGeneral Comments

This page lists non-professional experience in electronics, and other subjects relevant to engineering. It is not in any way exhaustive; such a page would be full of irrelevant detail.

Some items were constructed from kits, though in most cases modified (this is indicated in the comments below). That said, the majority of the high level and circuit designs were original. Of course, all test/integration activities were home-based.

Goto top of this pageAudio Electronics

Some Projects Design, and construction of various hi-fi components.

Design, and construction of a PA mixing desk, amplifiers, multicore cable, and associated remote electronics.
Hardware Skills Analogue
  • high quality audio electronics (ranging from low level microphone inputs to >100W RMS amplifiers)

Interface

  • earth loops and EMC considerations.
  • sending audio signals (even at 1mV level) moderate distances without significant degredation.
Debug/Test Skills General Testing
  • analogue oscilloscopes for audio debug
Support Activities Thermal design to allow loss of significant heat from a small box without causing excessive temperature rise within the box.

Mechanical design of equipment suitable to be used as a mobile PA.

Goto top of this pageComputer Hardware

Some Projects Construction of a 'Cortex' computer from a kit purchased from Powertran (in 1983), and various kit upgrades.

Design/build other enhancements to the Cortex, including:

  • expand from 64k RAM to 256k RAM,
  • add parallel printer port,
  • add expansion interface.
Hardware Skills Digital
  • standard logic,
  • wiring/grounding techniques to allow 'touchy' digital circuits to operate reliably without a ground plane (e.g. a compact 256k byte DRAM board using 32 64kx1 DRAM chips).
  • 9995 microprocessor
Software Skills Minor operating system upgrades to support hardware changes. Coding in 9995 assembley language.
Debug/Test Skills General Testing
  • analogue oscilloscopes for digital debug

Goto top of this pageDisco/Stage Lighting

Some Projects Design and construction of Mk.1 and Mk.2 lighting controllers - both were standalone sound-to-light controllers.

Design and construction of Mk.3 lighting controller. This could be either computer controlled (Cortex or Sinclair QL) or manually controlled for stage use, with remote mains boxes connected via a multicore cable.
Hardware Skills Analogue and Mixed Signal
  • general analogue design, filters, intelligent signal detection/thresholding
  • audio electronics

Digital

  • standard logic, PALs - for bus interface,
  • DataIO ABEL/AHDL for PAL programming data generation (done at work)
  • 9995 (Cortex) and 68008 (QL) microprocessors

Interface

  • audio input
  • grounding, audio EMC considerations
  • 0V switched mains outputs - Triac switched with opto-isolated control inputs
Software Skills Medium-size programmes for embedded real-time control; split between a user interface and a real-time hardware control routines. User interfaces written in BASIC (Cortex and QL); real-time routines in 9995 assembler (Cortex) and 68008 assembler (QL)
Debug/Test Skills General Testing
  • analogue oscilloscopes for analogue and digital debug
Support Activities Thermal design to allow loss of significant heat from a small box without causing excessive temperature rise within the box.

Mechanical design of equipment suitable to be used as a mobile lighting rig.

Goto top of this pageSystem Software

Some Projects Enhancements to the Cortex' operating system:
  • add a disk cache,
  • improved support for memory above the 64k point.

Write a C compiler (in Cortex BASIC; based on one written earlier in C).

Write a word processor and text formatter (using the C compiler) - used for various letters, reports, etc. over many years - including University final year report.
Software Skills Various applications programmes and operating system enhancements. Written in BASIC and 9995 assembler

Goto top of this pageDIY

Some Projects The 'enthusiastic' side of DIY, including
  • strip and rebuild a kitchen, involving major modification to the existing units,
  • complete house rewire,
  • move taps, radiators, pipes; replace loft water tank,
  • knock out and rebuild under-stairs cupboard.
Support Activities General mechanical awareness to allow design and construction to be undertaken without problem.

Goto top of this pageLanguages

Languages French and German.
Listening/speaking Moderate, after a short time adjusting back to the language
Reading Moderate
Writing Moderate but slow; dictionary generally necessary for vocabulary
Limitations Main limitation is vocabulary; this begins to build back after a short period exposed the language
Recent use 1996-1999: little - mostly in shops/restaurants on holiday; occasional conversations with foreign visitors.

1986-1996: moderate - many solo cycle tours undertaken, so relied on foreign languages for general conversation in addition to basics like finding things to eat and places to stay.

Goto top of this pageGeneral Computing

This covers the period up to March 1999; for the period following that see Career > Time off Engineering (1) and Career > Time off Engineering (2).

Computer System
Software

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Curriculum Vitae > Career ... > Home and Hobbies / John Dubery / 8 April 2000