Techy odds and ends

Cheap and Cheerful and gets the job done. Edit 07-Aug-2023: 19 months after buying this robot and using it every few days, it is dead. Mechanical failure means that one of the wheels is no longer connected to the motor that drives it, so the robot basically goes round in small circles. If you're looking for a smart appliance with all the bells and whistles then this is not it, but it doesn't pretend to be it anyway. This is an entry-level vacuum cleaner robot that fumbles around more or less randomly, cleaning up whatever is in its path. The reason I bought this is because I wanted to see how well the technology coped with a small home on one floor that really is quite cluttered to be honest. If it doesn't cope well, then no great loss. If it does, then I know I can invest a bit more when this one comes to the end of its life. The robot comes with an infra-red remote control allowing you to access its basic features: auto clean, room clean, edge clean, spot clean an...

First of all, let's get one thing out of the way. It's a major thing that you always need to bear in mind when participating in social media in order to enjoy it safely. Your own safety is not the only thing that depends on this, that of your friends and family does, too. Social media is not a safe haven. There. I said it. Social media is open to anyone, not just the "good guys" like you and your friends. The "bad guys" are also out there and they gradually glean snippets of information from you and others that help them build up a profile allowing them to impersonate you, take over your social media account or even perpetrate identity theft. Any of the above can ruin your reputation and your credit rating and get you into trouble with the law if a crime is committed using your identity. That is, unless you deprive the bad guys of this information... Don't even feed them misinformation either because they can detect patterns in tha...

It's about a week since I bought one of these so I thought I'd jot down some of my first impressions of the timepiece. My overall impression is positive. There are a couple of negative points that I'll deal with but, on the whole, I like this watch. The build strikes me as being sturdy. There is no play in the crown or in the buttons and their operation is met with a reassuring amount of smooth friction. The mechanism for setting the watch is slightly unconventional but it actually makes sense. Most analogue watches with date usually allow you to set the date by pulling the crown out to a first position, and then to set the time by pulling the crown out to a second position. This watch does things slightly differently because it also has to allow you to calibrate the chronograph before you use it for the first time. With the crown in the first position you can zero the chronograph's minutes hand (10 o'clock dial) and you can set the date by rotating the h...

We've all seen those status updates from friends stating that they got 9 out of 10 answers right to a so-called impossible test claiming that " Nobody will get more than 60% of these right!" or something similar, haven't we? Let's look at how these things work, what they do and why they do it. Before going any further, help yourself to a decent dollop of cynicism or you're going to be very disappointed in social media. Remember the golden rule: if it looks too good to be true, then the chances are that it is not true. If there is the remotest possibility that something happening on social media could be something other than what it looks like, then it is not what it looks like and someone is trying to pull a fast one for profit in some way. Are the people setting these quizzes doing it out of the goodness of their hearts for the enrichment of the human race? Of course not. They're doing it to make money . So how do they make their money? What is their...

This is a little foray into number theory and presents one method of calculating the value of \(\pi\). It involves using a program to perform iterative calculations, so in order to minimise the impact of compounded rounding errors, it makes sense to use a computing device that operates with sufficient precision. I chose the SwissMicros DM42 for this because it uses Thomas Okken's Free42 Decimal under the hood, which offers around 34 digits of precision. The DM42 is also extremely fast, particularly so if connected to a USB port while operating because it more than triples the CPU clock compared to battery-powered operation. Back in 1735, the Swiss mathematician, astronomer (and a few other things besides) Leonhard Euler stated, and proved in 1741, that as the number \(n\) tends towards \(\infty\), the probability that two natural numbers \(a\) and \(b\) less than or equal to \(n\) are coprime, i.e. that \(a\) and \(b\) share no common divisor other than \(1\), tends towards ...

Am I a good photographer? Am I heck! But I do want to learn, and think the only way to learn techniques that are equally valid both in digital photography and in traditional 35mm film photography is to use a reflex camera with interchangeable lenses. A compact job won't cut it. A camera phone? Forget it! So, bit of a mid-life crisis :) I splurged out some of my savings on a Canon EOS 800D back that came with an 18-55mm zoom lens. I also bought a couple of different lenses to use with it. The 800D is not a professional camera. It's amateur but high-end amateur. I didn't want to spend huge amounts of money on something that will only be a passing fad, but then again I wanted to put enough into it to give me the best chance of seeing good results and being able to monitor progress. The sensor is not a full-frame sensor, it's an APS-C sensor but the results are still pretty good. The lens that came with the camera in a kit is an "EF-S 18-55m f/4-5.6 IS STM...

A while back, another member of the MoHPC forum mentioned a program he'd written for the HP-41C that allows the user to manage multiple alpha registers. I responded saying that I had written something similar many moons ago that behaved like a LIFO (last-in-first-out) stack rather than an indexed array of datasets and said that I'd look it up. I have no idea whatsoever what I did with my little utility so I decided to rewrite it, purely and simply. So here it is. NB: This program creates and manages a data file in Extended Memory called "ASTACK". If you already have a file of that name, it will be deleted! Note also that running these programs uses Flag 01 and trashes registers R07-R10. Finally, since this uses Extended Memory, you will need to run this on a 41CX or SwissMicros DM41, or on a 41C or 41CV with the "X-Function" module. The size of the data file created in Extended Memory depends on the depth of the alpha stack that you want to crea...