{"id":252,"date":"2012-10-22T10:50:19","date_gmt":"2012-10-22T09:50:19","guid":{"rendered":"https:\/\/howiem.org\/wordpress\/?p=252"},"modified":"2012-10-22T10:50:19","modified_gmt":"2012-10-22T09:50:19","slug":"tiny-stepper-motors","status":"publish","type":"post","link":"https:\/\/howiem.org\/wordpress\/2012\/10\/22\/tiny-stepper-motors\/","title":{"rendered":"Tiny stepper motors"},"content":{"rendered":"<p>If you&#8217;re ever in a posh car or on an expensive motorbike, you&#8217;ll sometimes notice that when you turn the ignition on, the speedo and rev counter dials do a quick self-calibration, moving their indicator needle all the way round the dial and back to zero again.<\/p>\n<p>Instead of using a traditional meter mechanism (a simple coil and magnet), they use a tiny computer-controlled stepper motor. Here&#8217;s one removed from a dial:<\/p>\n<p><img decoding=\"async\" title=\"Hosted by imgur.com\" src=\"http:\/\/i.imgur.com\/4fqLw.jpg\" alt=\"\" \/><\/p>\n<p>The metal shaft sticking out used to have a little plastic indicator needle on the end. Inside, they&#8217;re more like a watch mechanism than a traditional stepper motor:<\/p>\n<p><img decoding=\"async\" title=\"Hosted by imgur.com\" src=\"http:\/\/i.imgur.com\/RQEdG.jpg\" alt=\"\" \/><\/p>\n<p>The tiny black cog in the middle is magnetic, and sits in the round gap in the metal frame just to its left.<\/p>\n<p><img decoding=\"async\" title=\"Hosted by imgur.com\" src=\"http:\/\/i.imgur.com\/RZygN.jpg\" alt=\"\" \/><\/p>\n<p>Power up the two coils in the right sequence, and it drives the tiny cog round, in turn moving the other cogs which move the indicator needle.<\/p>\n<p>These are more traditional stepper motors, though still very tiny:<\/p>\n<p><img decoding=\"async\" title=\"Hosted by imgur.com\" src=\"http:\/\/i.imgur.com\/BX00B.jpg\" alt=\"\" \/><\/p>\n<p>I dug them out of a tiny camcorder. The shorter one controlled the focussing lens, while the longer one controlled the zoom. The little chip on the left is an Atmega168 &#8211; similar to the chip in an Arduino. With luck the chip&#8217;ll have enough power to drive the motors directly. Not sure yet what I&#8217;m gonna get the motors to do, exactly, but whatever it is it&#8217;ll be tiny and very cool. Yeah.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>If you&#8217;re ever in a posh car or on an expensive motorbike, you&#8217;ll sometimes notice that when you turn the ignition on, the speedo and rev counter dials do a&#8230;<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,1],"tags":[],"class_list":{"0":"post-252","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-electronics-and-hackery","7":"category-uncategorized"},"_links":{"self":[{"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/posts\/252","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/comments?post=252"}],"version-history":[{"count":0,"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/posts\/252\/revisions"}],"wp:attachment":[{"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/media?parent=252"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/categories?post=252"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/howiem.org\/wordpress\/wp-json\/wp\/v2\/tags?post=252"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}