MAY 25
A new Blog section for musings and small projects.
OCT 24
Updates to A Simple Model of Relativity .
JUL 24
Some thoughts on a basic radio telescope project for the amateur inspired by memories of one in the 1970s.
JUN 24
Various recent updates to Ladybird Radio, including a possible explanation for its quirky design and a recent mod which means R5L can be easily received without using regeneration. Smooth Radio now also gone from AM in the UK. Also on the reception of SW on the Transistorized Crystal Radio.
MAR 2024
Ladybird Radio - update to stations received; also to comments on the explanation of regeneration in the book. Highlighted in bold.
FEB 2024
New page - A Simple Model of Relativity .
Ladybird Radio - update/correction to stations received - including Radio Caroline :-) - and some comments on the explanation of regeneration in the book. Highlighted in bold.
JAN 2024
Now getting the laser communicator to work with a higher gain amp.
OCT 2023
Update to effect of using hand to increase signal of stations received with the Ladybird Radio.
APR 2023
Updates to stations received with the Ladybird Radio, including possibly a Saudi station, the most distant received so far.
FEB 2023
Updates to MIDI Interface and Sequencer to allow recorded sequences to be saved to on-board EEPROM and clarification about the wiring of the MIDI socket to opto-coupler.
JAN 2023
Another unwelcome reminder of the phasing out of broadcasting on AM by national radio stations here in the UK as Absolute Radio ends transmissions on MW as of this month. That's one station less to pick up on my home-built radios and it was one I would often happily listen to, so I will miss tuning in. In a few years, at least with suitable coils fitted, there will likely still be SW stations to receive, but I'm not sure I'm going to enjoy listening to Chinese or Romanian stations quite as much! The same fate awaits FM broadcasts too with the move to digital, even though I understand DAB to be inferior at least in this country. As the airwaves fall silent after 100 years, how though to appreciate and enjoy (legally!) an otherwise working antique radio?
Updates to MIDI Interface and Sequencer and code, including changes to stored sequence, note lengths and interval between notes. Plus now using integer variables for calculating PWM duty value, rather than slower floating points variables and using MIDI key to cycle through recorded note length, rather than dedicated keys for each.
DEC 2022
New item: MIDI Interface and Sequencer for Gakken synth - with code
New item: Analogue Step Sequencer, a Baby 8, used with a Gakken MX-150 synth, and some thoughts about a possible Mega 8 for the future
NOV 2022
The Ladybird Radio in reflex receiver mode; for optimal regeneration now using a smaller value capacitor between first transistor and diode detector.
OCT 2022
Ladybird Radio: new section on regeneration stage, recent updates now rolled into main text rather than as addenda
Transistorized Crystal Radio: reflex receiver hack tried out; use of regeneration considered
SEP 2022
Ladybird Radio: what a difference a new aerial has made!
Transistorized Crystal Radio: new section on performance
AUG 2022
New page on the Ferguson Tidal Clock
JUL 2022
Ladybird Radio: some updates - changes in reception, plus some general observations
JUN 2022
Spectrum Pages & Programs
New images added for Mandelbrot Set zooming in from 10x to 640x magnification
MAY 2022
Spectrum Pages & Programs: other
Pythagorean Triples - a new program using a formula known to the Babylonians.
Highest Common Factor - a new program using an algorithm from the time of the Ancient Greeks.
Spectrum Pages & Programs: Lagrange Points
code for placing an object near an L point: pictures of what happens near L4 and instability of paths at L1 and L2;
enhanced version with movement now in 3 dimensions
ability to show the path of an object in 3D by means of a stereoscopic pair of images
(correction to show view plane of (z,x), rather than (x,z))
APR 2022
Spectrum Pages & Programs
New programs for Mandelbrot & Julia Sets to show very nice banded contours in black and true white - scroll down the program pages to see these
A little more background information on the programs on the main Spectrum page
Orbits program - a Hohmann transfer orbit is depicted using thrusters to raise the height of the orbit half an orbit after being fired; work around for time display rounding errors; plus minor code changes.
All BASIC programs - apart from the Orbits one - have had their lines renumbered. See here for method. For some reason, though, it was unable to handle the aforementioned program, so that is unchanged!
Minor changes to Hanoi and Nim programs using Fuse to code statements with <>, which I'd not been able to do with the Qaop/JS emulator and for which I'd had to code some clumsy work-arounds earlier.
A new program - Lagrange Points - to simulate the motion of an object at one of 4 of these points in the Earth Moon system. Stability of L4 point demonstrated!
MAR 2022
Spectrum Pages & Programs
Tower of Hanoi puzzle - a new program inspired by one of the very first I wrote in the 1970s for a desktop programmable calculator
Orbits program - fix to minor bug in time display; comments on quirk of addition on the Spectrum.
3 new programs using Taylor series to calculate e**x, cos(x) and sin(x).
I've tweaked the Mandelbrot Set program to produce Julia sets for the iterative function (z**2) +c.
Assembly language source code now available for routines in the GoL and 1-D CA programs.
FEB 2022
Schools' Computer
Corrections to draft code based on feedback from Udo in Germany, for which many thanks!
Some more thoughts on using the Combitron-S or Combitronic to generate artillery tables. Do-able, I think.
Spectrum Pages & Programs
All programs renamed and with new headers
1-D Cellular Automaton - new example (the Sierpiński triangle)
Game of NIM - a new program loosely based on one of the very first I wrote in the 1970s for a desktop programmable calculator
Mandelbrot Set - contour mode
Neural Network - a 'new' program (from 1988!)
Prime Numbers - faster search
Slow Square Root - a new program based on one of the very first I wrote in the 1970s for a desktop programmable calculator
Strange Attractor - new program to display the logistic map
Turing Machine - initial tape data retained plus examples of a TM (add, copy)