Questions that are frequently seen on blog threads include:
- why are there so many different types of scope probe?
- which probe should I use?
- why is my signal doing this?
Those are very sensible, common and important questions – so, if you know where to look, there are good answers on the web. I’ve gathered together a small collection of high quality references that have helped me in the past. I hope they enable people to swiftly answer their common questions.
I wanted to resurrect the attractive digital clock I made in the early 1970s, but it’s been a very long time since it was interesting enough to bother hanging it on a wall. Mutating it into a “Vetinari Clock” has made it, once again, into a talking point.
You can buy modules that convert conventional crystal-controlled analogue clocks into Vetinari clocks, but they have disadvantages. Firstly they require more than minimal conceptual changes to my clock, e.g. timing being derived from a crystal rather than by counting the 50Hz mains cycles. More importantly it simply doesn’t look right: digits ticking over instantaneously have much less visual impact than a second-hand moving slower or faster. Hence I made my own module, and it turned out to be a short and fun hack. Continue reading
Digital clocks don’t look very exciting nowadays, but things were very different 40 years ago. Since it was the first LED display and first digital clock that friends and neighbours had ever seen, it became a talking point. One person even actively disliked it – because it showed her life ticking away. Presumably none of her mechanical clocks had a second hand.
Size: 8″ by 8″, with 0.7″ LEDs
I’ve a certain fondness for the clock because it is my earliest surviving hack, looks reasonably pretty, and is a memento of time spent building things with my father. I’d wondered about putting it back on the wall, but didn’t get around to it because – even if it worked – it would be boring and quaint rather than a talking point. Then I realised I could turn it into yet another Vetinari Clock, so that maybe it would once again be a talking point amongst normal mundanes. When I dug it out it still worked, slightly surprisingly.
Then as now, it was difficult to find cases that are æsthetically pleasing. The solution was to find a very 1970s style decorative ceramic tile, and to cut out a slot for the display. The case sides were made from widely available painted wooden moldings. Suitable bezels were unobtanium, so smoky perspex was cut to size, rounded off, and simply glued over the slot. Looks fine from normal viewing distance
So, what did I find inside? Continue reading
To most people in the early 70s, electronics equalled TV, radio, giant computers with whirling things and blinkenlights tended by white-coated priests in cavernous rooms, the relatively new concept of “solid-state hi-fi” audio and, if they thought about it, RADAR. So what has and hasn’t changed?