Sunday, 24 March 2019

Digital Counter

I'm still working with grid layouts and making sure they work properly in IE11... I'm also concerned with petrol prices at the minute at my local BP Garage... so I got to playing with digital readouts in preparation for making a CSS grid calculator and developed this. I'm using lodash merely because it helps with all the nice array functionality which we don't have in IE11.

Saturday, 23 March 2019


After my last post, I got to work on another Wireframe conversion from Python to JS using p5, this one is from issue 6: This is the code, simple eh? I did need a wee bit of help from PaweĊ‚ Dawczak as I'm not totally au fait with the vagaries of Python.
const segment_size = 50;
const angle = 2.5;
const phase_step = 0.3;
const wobble_amount = 0.8;
const speed = 4.0;
const width = 600;
const height = 600;
let seconds = 0;
let tail_pieces = [];
function setup() {
    createCanvas(width, height);
    tail_pieces = Array.from({
        length: 10
    }, (_, i) => ({
        img: loadImage('images/tail_piece.png'),
        x: null,
        y: null
        img: loadImage('images/tail_hook.png'),
        x: null,
        y: null
function draw() {
    seconds += 0.01;
    let x = width - (segment_size * 2);
    let y = height - (segment_size * 2);
    tail_pieces.forEach(function(p, index, arr) {
        p.x = x;
        p.y = y;
        const temp_angle = angle + wobble_amount * Math.sin(index * phase_step + seconds * speed);
        x += segment_size * Math.cos(temp_angle)
        y -= segment_size * Math.sin(temp_angle)
    tail_pieces.filter((p,index) => index % 2 === 0 && image(p.img, p.x, p.y));
    tail_pieces.filter((p,index) => index % 2 === 1 && image(p.img, p.x, p.y));

Wednesday, 20 March 2019


I love Wireframe magazine, mainly because it seems like a blast from the past where I eagerly bought the latest ZX Spectrum magazine for the game listing... then spent hours upon hours entering the code into the machine to play a game. I know there were often bugs, but the debugging was sometimes the best part. I know I'm not alone in this as at least Ben Collins joins me in an appreciation of debugging.

Where I'm sort of sad though is that most of the smaller listings are in Python and, while I can find my way around Python, I much prefer JS, so I've started converting the listings to JS using p5. I've translated the Parallax example from issue 3, but the one above (from issue 1) was the most challenging yet as I needed to re-architect the program to work with p5. It wasn't all that hard really, but it was fun, especially getting my head around the trigonometry.

This is the JS code, should you want to enter it yourself:

const width = 800;
const height = 400;
const drag = 0.8;
const particles = [];
const framerate = 10;
const speed = 60;

const explode = () => {
    const x = random(width);
    const y = random(height);
    for (var i = 0; i < 100; i++) {
            vx: speed * pow(random(1), 0.5) * sin(random(2 * PI)), 
            vy: speed * pow(random(1), 0.5) * cos(random(2 * PI)), 
            age: 0, 
            birth: new Date()

function setup() {
    createCanvas(width, height);
    stroke(255, 230, 128);

function draw() {
    if (frameCount % 10 === 0) {
    particles.forEach(function(p, index, arr) {
        if (p.age <= 2) {
            const age = new Date().getSeconds() - p.birth.getSeconds();
            point(p.x, p.y);
            p.x = p.x += p.vx * p.age;
            p.y = p.y += p.vy * p.age;
            p.vx = p.vx * Math.pow(drag, p.age);
            p.vy = p.vy * Math.pow(drag, p.age);
            p.age = age;
            arr.splice(index, 1);

Thursday, 14 February 2019

Dom’s PiWars contribution – Arvind

NOTE: Cross-posted from here

Arvind and I met the week before last for a quick chat so I could write this, and it's taken me this long to have time to write up the conversation. I can only blame the vagaries of Internet Explorer 11 messing with my workflow; it's so frustrating to have something that looks and works just as it ought to in every browser under the sun, only for our QA to come along and test it in IE11 and notice that it's borked. It's a shame that a significant proportion of our customers use it, despite the recent advice from Microsoft to avoid using it as the default browser.

Ah well, back to talking about Arvind. I should approach describing Arvind by giving some context. In the dim and distant past, I moved from a job as a forensic psychiatric nurse to nursing on nights in an acute psychiatric ward in Cambridge.

Not long after starting there the latest change in nurse education occurred and we who worked nights were asked to mentor student nurses for a compulsory set of nights. I only managed to mentor two before trends changed again and they were no longer required to do some nights before qualifying.

One was the daughter of my friend and boss at the time, and we're still friends though she's no longer a nurse. I don't think she nursed for much longer after finishing her training before becoming a teacher. Here I am kicking myself for not remembering if she was a trained teacher before nurse training or if she went for teacher training afterwards - whatever though: we still keep in touch, so I'm guessing it wasn't working alongside me that put her off nursing.

The other was Sally, Arvind's wife, and I kept abreast of what she was doing but she worked on a different site, and despite us both living afloat on the Cam for a while, we lost touch. My divorce happened, and it turns out that, like many such things in Cambridge, my next wife knew Sally, so I kept up-to-date by proxy.

Then years and a different career happened before someone clocked my geeky t-shirt at the gym and introduced me to Ely Makers and Arvind got in touch and mentioned that his wife knew me. How cool eh?

Anyway, that's the context: on to Arvind. He works as developer like me but is far more adept at hardware type things like 3D printing and electronics whereas not even my Mum asks for my help with technology, and my wife has her own, individual, printer.

I was thinking of how best to describe him and while doing so was reading - for the third time - Dan Simmon's Hyperion (or The Fall of Hyperion) and was struck with something that one of the Pilgrims, Sol Weintraub, said. While describing his daughter, he says something about knowing someone who's sheer goodness makes one strive to be better themselves (having said that I can't find the relevant section now so I might be wrong about the character). I know a few of those people, and despite them making me feel distinctly un-good in comparison, I feel privileged to do so - even more so to be married to one (hey, it's nearly the 14th of February so I can't help myself).

So we know that Arvind is a developer and that I consider him intrinsically good, but what else is there to say about him? Well, one of the things that shaped my consideration was his emphasis on helping others and collaborating. He took exception (at least as much as he seems able to, anyway) at my hesitation to share too many details of our final entry to PiWars this year, for instance.

I thought I'd better show some interest in the actual final product during our conversation and subsequently learnt about the debate about whether to use tracks or wheels and also about stepper motors (which sound fascinating). The thing that does stand out is that while Arvind isn't organising our team, he is one of the many pillars of Ely Makers and without his enthusiasm, we'd be all the poorer.

We, of course, discussed our shared profession, especially in the context of the current divide that seems to be occurring with those who sling HTML, CSS and minimal JS becoming an almost different animal from those who dig deep into whatever the favourite JS Framework is at the minute. This dichotomy is something of a new debate and was brought to my attention by the article by Chris Coyier called The Great Divide, give it a read: it's fun.

Along with the discussion of our jobs we looked at the broader aims of Ely Makers, and there seem to be two principal aims. These seemed to me to be to encourage people to get involved, while also remove the fear which some feel towards technology. I was reminded of the Men's Shed Movement, though the club aims to embrace all genders and abilities. Arvind want to encourage all, so I guess calling it a Men's Shed-like thing is wrong, as all are welcome... let's call it a Shed Movement instead ;-)

I guess even calling it a Shed Movement might be incorrect as Arvind is keen to encourage community and collaboration, not only within Ely Makers but amongst other Makers and the wider community. Thinking about it that seems to be the ethos of all involved with loads of us pitching in to put on events, if not as part of Ely Makers then wider afield (two of us a Code Club volunteers). I guess this is echoed right there on the front page of our website:

Ely Makers is a friendly network of people of all ages with an interest in Science, Technology, Computers and Electronics. The group is based in Ely, Cambridgeshire although anyone is welcome to join.

To sum up, as this post is late and I need to do another over the coming weekend, if you have a chance to meet Arvind or Sally, then please do say hello. Should you be knocking around Ely over the weekend when we're running a session, then please do pop in and check out the stuff we're doing. It's worth keeping a weather eye on our Events & Dates page.

Wednesday, 30 January 2019

Dom’s PiWars contribution – Introduction

NOTE: Cross-posted from here

I am perhaps the least active member of the Pi Wars Team, but then again I did say that I would be. Arvind kindly asked if I’d like to help and of course I said yes. I then realised that there was likely to be very little I could do, being as inept as I am with anything other than the odd bit of writing and wrangling code (HTML, CSS and JS) into something that resembles something that you’d like to – hopefully – interact. I lurk in our piwars Slack channel and try to contribute here and there, though that generally involves merely adding a cute emoji to someone’s efforts, without any clear understanding of what they have done. It all looks intelligent and sophisticated, but I don’t have a clue of the effort involved because my mind doesn’t work that way. Give me a Lego set and some instructions, and I’m away with the fairies for a couple of hours. Ask me to create something physical or decipher the bands on a resistor, and I’ll look up instructions on YouTube (actually, one competency I do have is in the realms of Archery… when once asked who our coach was in an archery competition we had to answer, “YouTube”).

So, with all that out of the way, I’m going to try and write about what we’re (I use the term “we”, but you know…) doing concerning Pi Wars. I appreciate that there might be some level of competition so I’m going to steer well away from the hard facts and talk about the things that interest me: the people on our team that are doing the hard stuff and making Lego without the instruction book – I might even get permission to talk about what they’re doing. Over the next few weeks, I’ll be interviewing some (if not all) of the team so that you can get some insight into their personalities if or when you meet them at the final competition.

Of course, should you have any questions for the team, please don’t hesitate to get in touch and I’ll do my best to get an answer for you, subject to the solution not being sensitive regarding the competition?

Tuesday, 22 January 2019

Google's GDPR fine

So Google was hit with a $57 million GBPR fine, instigated by France, on Monday 21st January 2019. I took to thinking about this today and seeing as Google posted its first $100 billion in sales in 2018 I calculated that this represents something like 0.057% of its sales... or 4.99651328 hours (0.057% of (1 year)). Please check my math though as my billions are different from modern billions.

Friday, 23 November 2018

Finding the index of an array of objects by one of the object's properties

I've been doing a shed load of work with lodash of late and, seeing as I've not posted in an age, I thought I'd illustrate an issue I was working on today.

I needed to pass an element of an array to a Vue component but needed a specific one identified by another object. We use lodash so thought I'd make use of findIndex and isEqual and came up with this:

const obj = {
    id: 1,
    name: "fred"

const arr = [{
    a: "B",
    s: {
        id: 1,
        name: "fred"
}, {
    a: "A",
    s: {
        id: 2,
        name: "fred"

alert(arr[_.findIndex(arr, (a) => _.isEqual(a.s, obj))].a);

Heat eh?