AntiMath

Using fullPage.js to make a vertical split-screen parallax

posted in CSS jQuery on October 9, 2017 - 0 Comments

fullPage.js, as its author states, is a jQuery plugin which allows you to “create full screen pages fast and simple”.

How about using it to make a split-screen parallax fast and simple ?

First the required HTML structure:

<div id="splitscreen">
  <div class="section">
    <div class="column column-left">Left Side</div>
    <div class="column column-right">Right Side</div>
  </div>
</div>

Then init the fullPage.js, and customize the settings to your taste.

$(document).ready(function() {
 $('#splitscreen').fullpage({
   navigation: false,
   scrollingSpeed: 1000,
 });
});

Now the CSS for the split-screen:

#splitscreen > .section .column-left {
  float: left;
  width: 50%;
  color: #000;
  background: #fff;
}

#splitscreen > .section .column-right {
  float: right;
  width: 50%;
  color: #fff;
  background: #000;
}

#splitscreen > .section .column-left {
  transition: all 1s ease 0s;
  transform: translateY(100%);
  backface-visibility: hidden;
}

#splitscreen > .section .column-right {
  transition: all 1s ease 0s;
  transform: translateY(-100%);
  backface-visibility: hidden;
}

#splitscreen > .section.active {
  z-index: 1;
}

#splitscreen > .section.active .column-left {
  transform: translateY(0);
}

#splitscreen > .section.active .column-right {
  transform: translateY(0);
}

#splitscreen > .section.active ~ .section .column-left {
  transform: translateY(-100%);
}

#splitscreen > .section.active ~ .section .column-right {
  transform: translateY(100%);
}

/* prevent fullpage from translating the page */
#splitscreen {
  transform: translate3d(0px, 0px, 0px) !important;
}

#splitscreen > .section {
  position: absolute;
  top: 0;
  left: 0;
}

Split screen parallax demo.

CSS, custom, how to, jQuery, jQuery plugin

CSS proportional box and vertical align

posted in CSS on July 14, 2017 - 0 Comments

Proportional box:

.box {
    width: 100%;
    height: 0;
    padding-top: 56.25%; /* 16:9 */
}

16:9 ⇔ 9/16=0.5625 ⇒ 0.5625*100=56.25%

Vertical alignment 1:

<div class="valign">
    <div class="valign-inner">
       Vertically aligned content.
    </div>
</div>

.valign {
    display: table;
    table-layout: fixed;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}

.valign-inner {
    display: table-cell;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    vertical-align: middle;
}

Vertical alignment 2:

.valign {
    display: flex;
    align-items: center;
    justify-content: center;
}

.valign-inner {
    flex: 1;
}

Proportional box with background image and vertically centered content:

<div class="box" style="background-image: url('path/to/image');">
    <div class="box-inner">
        <div class="valign">
            <div class="valign-inner">
               Vertically aligned content.
            </div>
        </div>
    </div>
</div>

.box {
    position: relative;
    width: 100%;
    height: 0;
    padding-top: 56.25%; /* 16:9 */
    background-repeat: no-repeat;
    background-position: center center;
    background-size: cover;
}

.box-inner {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    text-align: center;
}

.valign {
    display: table;
    table-layout: fixed;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}

.valign-inner {
    display: table-cell;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
    vertical-align: middle;
}

CSS

fullPage.js – always scroll from top within sections

posted in jQuery on December 15, 2016 - 0 Comments

Scroll long sections always from top.
This works only for section without slides.

$('#fullpage').fullpage({
  scrollOverflow: true,
  onLeave: function(index, nextIndex, direction){
    $('.fp-scrollable').each(function() {
      var iScrollInstance = $(this).data('iscrollInstance');
      iScrollInstance.scrollTo(0,0, 2000);
    });
  }
});

jQuery plugin

Novus 4510 Mathematician

posted in electro math on November 20, 2016 - 0 Comments

A friend gave me this National Semiconductor Novus 4510 Mathematician scientific calculator made in 1976, and I couldn’t resist taking it apart.

It is an interesting calculator, simply by being a Reverse Polish notation (RPN) machine.

On the inside, the hardware it’s pretty simple, with only two IC’s and a 9-digit 7-segment bubble LED display, mounted on a single side fiber glass PCB. The keyboard seems pretty robust and it’s fixed to the front part of the case, while the PCB it’s mounted on the back part of the case, connected through a flat flex cable.

IC1: MM5760N – 24 pin DIP, Slide Rule Processor
IC2: DS8864N – 22 pin DIP, Segment-Digit Parallel-Input Display Driver

basic computing

Simple HTML5 placeholders fallback for IE9 and older

posted in CSS jQuery on October 14, 2015 - 0 Comments

I hoped I will never hear about IE9 and its lack of support for the placeholder attribute, … I had high hopes.

I’ve boiled a simple fallback, late in the evening and in a rush, using IE conditional comments for browser detection.

<!--[if IE 8 ]>    <html class="ie8 lt-ie10"> <![endif]-->
<!--[if IE 9 ]>    <html class="ie9 lt-ie10"> <![endif]-->
<!--[if (gt IE 9)|!(IE)]><!--> <html><!--<![endif]-->

$(document).ready(function() {

	// HTML5 placeholders fallback for IE9 and older
	if ($('html').hasClass('lt-ie10')) {

		// add the placeholder text as value
		$('textarea, input:text').each(function() {
			$(this).attr('value', $(this).attr('placeholder'));
		});

		// clear form fields on focus
		$('textarea, input:text').on('focus click', function(){
			if (this.value == this.defaultValue) {
			this.value = '';
			}
		}).on('blur', function(){
			if (this.value == '') {
			this.value = this.defaultValue;
			}
		});
	}

});

form fields, internet explorer, simple, toolbox

Random start cycle

posted in jQuery on October 9, 2015 - 0 Comments

function randomBox(randomItem) {

  randomItem = $(randomItem);

  var random = Math.floor(Math.random() * randomItem.length);

  randomItem.eq(random % randomItem.length).addClass('active');

  function startRand() {

    var current = randomItem.parent().find('.active');

    if ( current.is(':last-child') ) {
      current.removeClass('active');
      current.siblings(':first-child').addClass('active');
    } else {
      current.removeClass('active');
      current.next().addClass('active');
    }

    setTimeout(function(){startRand()}, 2500);
  }

  startRand();
}

randomBox('.list > .item');

cycle

CSS target elements by partial class or ID name

posted in CSS on August 20, 2015 - 0 Comments

This can simply be achieved using attribute selectors.

div[attr^="elem"]

// Matches any “div” with an “attr” attribute that begins with “elem”.

div[attr$="elem"]

// Matches any “div” with an “attr” attribute that ends with “elem”.

div[attr*="elem"]

// Matches any “div” with an “attr” attribute that contains the substring “elem”.

div[attr|='elem']

// Matches any “div” with an “attr” attribute that starts with “elem” and may continue with a dash (ex. “elem-string”).

Ex. target a “form” with the id=”login-[ID]-form” (where [ID] is a random form ID)

form[id^="login"]
// or
form[id^="login"][id$="form"]
// or
form[id*="login"][id*="-form"]
// or
div[id|='login']

Network cable tester

posted in electro on May 17, 2015 - 2 Comments

Build a network cable tester with just two cheap integrated circuits and a few parts from the ‘junkbox’.
This cable tester, tests all the 8 wires in a network cable in one move, if one of the 8 LEDs does not lit up, it means that the wire corresponding to that LED is faulty.

You need:

1 x 4017 decade counter,
1 x 555 timer,
8 x LEDs,
2 x 8P8C modular connector (RJ45),
8 x 100Ω resistor,
1 x 10KΩ resistor,
1 x 15KΩ resistor,
1 x 4,7µF capacitor.

The yellow LED has no special significance, I only had 7 green LEDs.

A good ideea would be that every LED have the color of the corresponding wire, and maybe a switch for the T568A and T568B standards.

DIY, network, simple, toolbox

CSS propeller

posted in CSS on May 3, 2015 - 0 Comments

Just for fun!

See demo CSS3 Keyframe Animation Propeller
(Do not open the demo page, if you do not tolerate high speed changing frames!)

<html>
  <head>
    <title>CSS3 Propeller</title>
  </head>
  <body>
    <div class="propeller"></div>
  </body>
</html>

.propeller {
  position: absolute;
  left: 0;
  right: 0;
  top: 0;
  bottom: 0;
  margin: auto;
  
  width: 0px;
  height: 0px;
  border-width: 200px;
  border-style: solid;
  border-color: #fff #00f #fff #00f;
  border-radius: 50%;

  -webkit-animation-duration: 0.2s;
  -moz-animation-duration: 0.2s;
  -o-animation-duration: 0.2s;
  animation-duration: 0.2s;

  -webkit-animation-name: rotateCircle;
  -moz-animation-name: rotateCircle;
  -o-animation-name: rotateCircle;
  animation-name: rotateCircle;

  -webkit-animation-iteration-count: infinite;
  -moz-animation-iteration-count: infinite;
  -o-animation-iteration-count: infinite;
  animation-iteration-count: infinite;

  -webkit-animation-timing-function: linear;
  -moz-animation-timing-function: linear;
  -o-animation-timing-function: linear;
  animation-timing-function: linear;
}

@-webkit-keyframes rotateCircle {
  from {
    transform: rotate(0deg); 
  }

  to {
    transform: rotate(360deg);
  }
}

@-moz-keyframes rotateCircle {
  from {
    transform: rotate(0deg); 
  }

  to {
    transform: rotate(360deg);
  }
}

@-o-keyframes rotateCircle {
  from {
    transform: rotate(0deg); 
  }

  to {
    transform: rotate(360deg);
  }
}

@keyframes rotateCircle {
  from {
    transform: rotate(0deg); 
  }

  to {
    transform: rotate(360deg);
  }
}

More on CSS animations you can find here:
https://developer.mozilla.org/en-US/docs/Web/CSS/animation
https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Using_CSS_animations
https://css-tricks.com/almanac/properties/a/animation
https://css-tricks.com/snippets/css/keyframe-animation-syntax

Animation, CSS, CSS3, Keyframe

SASS sqrt function

posted in CSS on March 24, 2015 - 2 Comments

There are times when a method of calculating the square root of a number is needed in SASS; for example calculating the sides of a right triangle, when the length of the hypotenuse is known, or the other way around, for a triangle mixin.

SASS provides us with some basic number operations, and there are libraries which implement more advanced math functions, but I wanted to experiment.

Using Newton’s method algorithm from Wikipedia, transcribed in SCSS scripting, we get the following:

@function sqrt($r) {
  $x0: 1; // initial value
  $solution: false;

  @for $i from 1 through 10 {
    @if abs(2 * $x0) < 0,00000000000001 { // Don't want to divide by a number smaller than this
      $solution: false;
    }

    $x1: $x0 - ($x0 * $x0 - abs($r)) / (2 * $x0) !global;

    @if ( abs($x1 - $x0) / abs($x1)) < 0,0000001 { // 7 digit accuracy is desired
      $solution: true;
    }

    $x0: $x1;
  }

  @if $solution == true {
    // If $r is negative, then the output will be multiplied with <a href="http://en.wikipedia.org/wiki/Imaginary_number">i = √-1</a>
    // (√xy = √x√y) => √-$r = √-1√$r
    @if $r < 0 {
      @return $x1 #{i};
    }
    @else {
      @return $x1;
    }
  }
  @else {
    @return "No solution";
  }
}

Which works, but looks too complicated.

We can simplify it into,

@function sqrt($r) {
  $x0: 1;
  $x1: $x0;

  @for $i from 1 through 10 {
    $x1: $x0 - ($x0 * $x0 - abs($r)) / (2 * $x0);
    $x0: $x1;
  }

  @return $x1;
}

Note: By default SASS computations are done with a precision of 5 decimals, if you need a higher precision use the “–precision N” (where N is the number of decimals) flag when compiling.

CSS, SASS, SCSS

Get the closest next or previous integer in a sorted array of integers

posted in JS on November 24, 2014 - 2 Comments

// array = sorted array of integers
// val = pivot element
// dir = boolean, if true, returns the previous value

function getVal(array, val, dir) {
  for (var i=0; i < array.length; i++) {
    if (dir == true) {
      if (array[i] > val){
        return array[i-1] || 0;
      }
    } else {
      if (array[i] >= val) {
        return array[i];
      }
    }
  }
}

Example:

array = [0, 5, 7, 9, 22, 27];
pivot = 11;

getVal(array, pivot);        //returns 22
getVal(array, pivot, true);  //returns 9

Threshold voltmeter

posted in electro on October 5, 2014 - 0 Comments

threshold-voltmeter

This is not an actual voltmeter, it just “detects” if the input voltage is below or above a certain threshold. The threshold voltage is the breakdown voltage of a Zener diode.

I have seen this in a magazine described as an rudimentary car battery voltage indicator, recently I have used it as a protection circuit, just replaced the red LED with a relay, acting like a switch (closed when the voltage is under the threshold value and open if the voltage is grater).

Prevent inner elements trigger an event on the parent

posted in jQuery JS on August 17, 2014 - 4 Comments

Method 1
Stop propagation on inner elements before attaching an event on the parent.

$('#parent a').on('click', function(event){
  //stop the event bubbling up to the parent
  event.stopPropagation();
});

$('#parent').on('click', function(event){
  //attach event on the parent
  alert('Parent element clicked!');	
});

Method 2
Check if the event target matches the designated target.

$('#parent').on('click', function(event) {
  if(event.target == event.currentTarget) {
    alert('Parent element clicked!');
  } else {
    alert('Child element clicked!');
  }
});

Method 2.1
Check if the tag name of the event target matches a certain element.

$('#parent').on('click', function(event){
  if(event.target.tagName.toLowerCase() === 'a'){
    alert('Child anchor element clicked!');
  } else {
    alert('Parent element clicked!');
  }
});

javascript, toolbox

Hide popup when clicking outside

posted in jQuery on June 2, 2014 - 4 Comments

//show popup when clicking the trigger
$('#trigger').on('click touch', function(){
  $('#tooltip').show();
});			

//hide it when clicking anywhere else except the popup and the trigger
$(document).on('click touch', function(event) {
  if (!$(event.target).parents().addBack().is('#trigger')) {
    $('#tooltip').hide();
  }
});

// Stop propagation to prevent hiding "#tooltip" when clicking on it
$('#tooltip').on('click touch', function(event) {
  event.stopPropagation();
});

Demo

how to, jQuery, toolbox

4 bit relay computer

posted in electro on May 25, 2014 - 3 Comments

This is my first 4 bit adder built with nothing more than relays.

4bit-adder-schematic

The forest of wires on the right are used to set the input values (in the picture Input1 = 0100 (4 in base 10) and Input2 = 0101 (5 in base 10)), and the LEDs on the left are used as output indicators for the SUM (in this picture 1001 (9 in base 10)).

basic computing

Prevent bxSlider stop auto

posted in jQuery on April 14, 2014 - 0 Comments

Prevent bxSlider stop auto slides transition, when navigating through slides.

$(document).ready(function(){
	var slider = $('#slideshow').bxSlider({
		auto: true,
		stopAuto: false,
		startSlide: 0
	});
	
	$(document).on('click','.bx-pager-link',function() {
	    slider.stopAuto();
	    slider.startAuto();
	});
});

active slide, current slide, cycle, how to, jQuery plugin

Slide out hamburger menu

posted in CSS jQuery on March 28, 2014 - 2 Comments

It is known that the slide out menus ( or hamburger menus ) are the best way of making a menu usable for mobile.

This method uses jQuery in order to clone the markup of the desktop version menu, and make it slide out. Check out the demo.

<body>
	<div id="container">
		<div id="header">
			<div id="navigation">
				<ul>
					<li>
						<a href="#">Lorem Ipsum</a>
					</li>
					<li>
						<a href="#">Lorem Ipsum</a>
					</li>
				</ul>
			</div>
			<span id="toggle-menu">Menu</span>
		</div>
	</div>
</body>

$('#navigation').clone().prependTo('body').addClass('mobile-navigation').removeAttr('id');
$('div.mobile-navigation').prepend('<span class="close">Close</span>');

$('#toggle-menu').bind('click touch', function(){
	if( $('div.mobile-navigation').hasClass('open') ){
		$('div.mobile-navigation').animate({width: "0px"}, 300).removeClass('open');
		$('#container').animate({left: "0px"}, 300);
	} else {
		$('div.mobile-navigation').animate({width: "210px"}, 300).addClass('open');
		$('#container').animate({left: "-210px"}, 300);
	}
});

$('div.mobile-navigation span.close').bind('click touch', function(){
	$('div.mobile-navigation').animate({width: "0px"}, 300).removeClass('open');
	$('#container').animate({left: "0px"}, 300);
});

#container {
  position: relative;
  width: 100%;
}

.mobile-navigation {
  width: 0;
  height: 100%;
  overflow: hidden;
  position: fixed;
  right: 0;
  top: 0;
  z-index: 200;
}

Check out demo.

CSS, how to, jQuery, mobile, simple

Square wave generator with 7400 series chip

posted in electro on March 9, 2014 - 4 Comments

This is a simple and useful oscillator, built, using just a 7400 chip ( 4 NAND gates ) and very few other components.

7400-square-wave
7400-square-wave-pcb
square-wave-signal

thoughts: simple;