{"id":20,"date":"2014-09-17T00:00:53","date_gmt":"2014-09-17T00:00:53","guid":{"rendered":"http:\/\/www.wis.co.uk\/lego\/?p=20"},"modified":"2015-04-30T21:03:38","modified_gmt":"2015-04-30T21:03:38","slug":"clock-number-1","status":"publish","type":"post","link":"https:\/\/www.wis.co.uk\/lego\/clock-number-1\/","title":{"rendered":"Clock Number 1"},"content":{"rendered":"<p><a href=\"http:\/\/4.bp.blogspot.com\/-YWyQhxaF7H0\/U-0f7Vb9HTI\/AAAAAAAABXk\/Cm_3GwOGGAg\/s1600\/2014-08-14\"><img loading=\"lazy\" class=\" alignright\" src=\"https:\/\/images-blogger-opensocial.googleusercontent.com\/gadgets\/proxy?url=http%3A%2F%2F4.bp.blogspot.com%2F-YWyQhxaF7H0%2FU-0f7Vb9HTI%2FAAAAAAAABXk%2FCm_3GwOGGAg%2Fs1600%2F2014-08-14&amp;container=blogger&amp;gadget=a&amp;rewriteMime=image%2F*\" alt=\"\" width=\"320\" height=\"240\" border=\"0\" data-orig-src=\"http:\/\/4.bp.blogspot.com\/-YWyQhxaF7H0\/U-0f7Vb9HTI\/AAAAAAAABXk\/Cm_3GwOGGAg\/s1600\/2014-08-14\" \/><\/a>Now that I have moved into my man-cave, I am able to start working on a number of projects that have been on hold whilst we rebuilt the house. Stuff like rebuilding a computer, sorting out the XBMC media box, and stuff like that. And building cool things out of Lego.<\/p>\n<p>One of the projects that has been ticking over at the back of my mind is to build a clock. A quick internet search shows lots of ideas of building clock faces out of Lego, and <a href=\"http:\/\/www.mocpages.com\/moc.php\/3964\" data-blogger-escaped-target=\"_blank\">some<\/a> of <a href=\"https:\/\/www.flickr.com\/photos\/steampoweredbricks\/6763713913\/\" data-blogger-escaped-target=\"_blank\">these<\/a> are <a href=\"http:\/\/www.arthursacek.com\/2011\/07\/lego-clock-2011.html\" data-blogger-escaped-target=\"_blank\">very artistic<\/a>. A lot of work goes into making some of these designs, and eventually my clock will have an arty face as well.<\/p>\n<p>For the idea in hand, I am not content to use a purchased clock mechanism. The challenge is to build the mechanism as well. For this, Lego Technic is my weapon of choice, but there are a number of challenges:<\/p>\n<ul>\n<li>Lego axles are cross-shaped rather than round, and the gears have a cross-shaped hole in the middle so that the gears do not spin on the axle. The challenge is that a clock has two concentric axles for the hour and minute hand &#8211; three if you want a second-hand as well. So somewhere in the mechanism, at least one gear must be able to spin freely on the axle.<\/li>\n<li>It is considered extremely bad form among Adult Fans of Lego to deliberately damage one&#8217;s Lego. Therefore the drilling-out of the axle-cross in a gear is not permitted. Having said that, I confess to doing exactly that a number of years ago.<\/li>\n<li>The minute hand rotates sixty times faster than the hour hand. A gear ratio of 60:1 is required between the two concentric axles. Lego gears are available with 8, 16, 24, and 40 teeth (there are a few others too). I leave the maths as an exercise for the reader.<\/li>\n<\/ul>\n<p class=\"separator\"><a href=\"http:\/\/3.bp.blogspot.com\/-bP4tUHrYCFI\/VBn2JeQaCkI\/AAAAAAAABYk\/OiILSNMwtgE\/s1600\/IMG_1154s.jpg\"><img loading=\"lazy\" src=\"https:\/\/images-blogger-opensocial.googleusercontent.com\/gadgets\/proxy?url=http%3A%2F%2F3.bp.blogspot.com%2F-bP4tUHrYCFI%2FVBn2JeQaCkI%2FAAAAAAAABYk%2FOiILSNMwtgE%2Fs1600%2FIMG_1154s.jpg&amp;container=blogger&amp;gadget=a&amp;rewriteMime=image%2F*\" alt=\"\" width=\"640\" height=\"480\" border=\"0\" data-orig-src=\"http:\/\/3.bp.blogspot.com\/-bP4tUHrYCFI\/VBn2JeQaCkI\/AAAAAAAABYk\/OiILSNMwtgE\/s1600\/IMG_1154s.jpg\" \/><\/a><\/p>\n<p>Over the course of an hour in my cave the other evening, with paper, pen, and the calculator on my phone (a form of cheating), I worked out the gear ratios. I know I can look it up online, but that&#8217;s not so satisfying. Then I ran into another problem: how to make sure that the start and the end of the gearing end up on the same axle. I built and rebuilt the mechanism half a dozen times before I worked that out. Some problems can only be solved by trial and error. And the solution turned out to be quite elegant. The mechanism is seen here.<\/p>\n<p>On the front (in the lower part of the picture to the left) is a <a href=\"http:\/\/www.bricklink.com\/catalogItemPic.asp?P=6573\" data-blogger-escaped-target=\"_blank\">dark grey part<\/a>\u00a0, known as a &#8220;<a href=\"http:\/\/en.wikipedia.org\/wiki\/Differential_(mechanical_device)\" data-blogger-escaped-target=\"_blank\">differential<\/a>\u00a0&#8220;. This part is found in many of the Technic vehicle sets, and your car has one too. I use it here, because it has round axle-holes. The dark grey bit itself is driven by the small 8-tooth gear to its right. The axle through the middle is driven from the back of the mechanism (top of the picture).<\/p>\n<p><a href=\"http:\/\/1.bp.blogspot.com\/-TeyJOWzSO-A\/VBn2IplJqrI\/AAAAAAAABYY\/iHyLUlL_UAc\/s1600\/IMG_1152s.jpg\"><img loading=\"lazy\" src=\"https:\/\/images-blogger-opensocial.googleusercontent.com\/gadgets\/proxy?url=http%3A%2F%2F1.bp.blogspot.com%2F-TeyJOWzSO-A%2FVBn2IplJqrI%2FAAAAAAAABYY%2FiHyLUlL_UAc%2Fs1600%2FIMG_1152s.jpg&amp;container=blogger&amp;gadget=a&amp;rewriteMime=image%2F*\" alt=\"\" width=\"640\" height=\"480\" border=\"0\" data-orig-src=\"http:\/\/1.bp.blogspot.com\/-TeyJOWzSO-A\/VBn2IplJqrI\/AAAAAAAABYY\/iHyLUlL_UAc\/s1600\/IMG_1152s.jpg\" \/><\/a>So here I present, with a simple face to support the whole thing, version 1 of my Lego clock. There is no drive system yet &#8211; you have to turn the minute hand manually. But the hour hand rotates at exactly the right speed when you do so. My son called it a Saturday alarm clock &#8211; you can set it for exactly the time you want, and it will make absolutely no sound at that time on a Saturday, thus allowing you to have a lie-in. so practical.<\/p>\n<p>If I have nothing else to do on Saturday after my lie-in, I might start work on the drive mechanism. Episode 2 of this saga will follow in a few months&#8217; time. If you can&#8217;t wait for me to build mine, have a <a href=\"http:\/\/62bricks.com\/lego-clock\/\" data-blogger-escaped-target=\"_blank\">look<\/a> at <a href=\"http:\/\/www.ubergizmo.com\/2011\/11\/lego-digital-clock-is-awesome\/\" data-blogger-escaped-target=\"_blank\">what<\/a> <a href=\"http:\/\/www.nico71.fr\/tag\/clock\/\" data-blogger-escaped-target=\"_blank\">others<\/a> <a href=\"http:\/\/www.dsharlet.com\/2011\/01\/15\/lego-clock\/\" data-blogger-escaped-target=\"_blank\">have<\/a> <a href=\"http:\/\/arts.brookes.ac.uk\/news\/items\/080213-students-interactive-lego-clock.html\" data-blogger-escaped-target=\"_blank\">done<\/a>.<\/p>\n<p>(This post first appeared on my <a title=\"Blogspot blog\" href=\"http:\/\/princeofgonville.blogspot.co.uk\/2014\/09\/clock-number-1.html\" target=\"_blank\">Blogspot blog<\/a>\u00a0in September 2014).<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Now that I have moved into my man-cave, I am able to start working on a number of projects that have been on hold whilst we rebuilt the house. Stuff like rebuilding a computer, sorting out the XBMC media box, &hellip; <a href=\"https:\/\/www.wis.co.uk\/lego\/clock-number-1\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7,4],"tags":[6,8,5],"_links":{"self":[{"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/posts\/20"}],"collection":[{"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/comments?post=20"}],"version-history":[{"count":4,"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/posts\/20\/revisions"}],"predecessor-version":[{"id":34,"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/posts\/20\/revisions\/34"}],"wp:attachment":[{"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/media?parent=20"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/categories?post=20"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.wis.co.uk\/lego\/wp-json\/wp\/v2\/tags?post=20"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}