{"id":16970,"date":"2022-02-14T07:56:09","date_gmt":"2022-02-14T12:56:09","guid":{"rendered":"https:\/\/scruss.com\/blog\/?p=16970"},"modified":"2025-03-08T00:17:03","modified_gmt":"2025-03-08T05:17:03","slug":"slightly-imperfect-hoot-nanny-magic-designer-simulation","status":"publish","type":"post","link":"https:\/\/scruss.com\/blog\/2022\/02\/14\/slightly-imperfect-hoot-nanny-magic-designer-simulation\/","title":{"rendered":"Slightly imperfect Hoot-Nanny\/Magic Designer simulation"},"content":{"rendered":"\n<figure class=\"wp-block-image aligncenter size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/25km-25mk-65mm.png\" alt=\"round figure with three interlaced 6-fold curves picked out in red, green and blue\" class=\"wp-image-16971\" srcset=\"https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/25km-25mk-65mm.png 1024w, https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/25km-25mk-65mm-320x320.png 320w, https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/25km-25mk-65mm-160x160.png 160w, https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/25km-25mk-65mm-768x768.png 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">I even emulated the locating notches at the edge of the paper &#8230;<\/figcaption><\/figure>\n\n\n\n<p>Simulated (and not quite right yet) output from a &#8220;HOOT-NANNY&#8221; or Magic Designer, a proto-<em>Spirograph<\/em> toy that drew six-sided curves on round paper sheets. It was made by Howard B. Jones and Co. of Chicago, IL and first sold in 1929. The company&#8217;s better known for producing <a href=\"https:\/\/www.belfuse.com\/product-detail\/industrial-cinch-jones-plugs\">Jones Plugs and Sockets<\/a>, sometimes known as Cinch-Jones connectors. The &#8220;HOOT-NANNY&#8221; name was dropped when production moved to the Northern Signal Company of Saukville, WI.<\/p>\n\n\n\n<p>My eBay-acquired Magic Designer is quite beaten up, and doesn&#8217;t always produce accurate results. Here&#8217;s how one should look, from the instruction pamphlet:<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"998\" src=\"https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/hoot-05.jpg\" alt=\"diagram of the Magic Designer toy: central turntable holding paper is rotated by crank at bottom right. On the left are two crank discs (upper and lower) each with a crank pin that can fit into holes along two arms. These arms are joined at a pivot, and in the centre of this pivot is a pencil.\n\nThe upper crank disc can be moved in an arc relative to the lower disc. This is controlled by a locking shift lever on the right\" class=\"wp-image-16972\" srcset=\"https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/hoot-05.jpg 1024w, https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/hoot-05-320x312.jpg 320w, https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/hoot-05-160x156.jpg 160w, https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/02\/hoot-05-768x749.jpg 768w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><figcaption class=\"wp-element-caption\">I can&#8217;t shake the feeling this was originally something like an artillery ranging tool or suchlike<\/figcaption><\/figure>\n\n\n\n<p>As far as I&#8217;ve been able to work out, the parameters of the machine are:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>central turntable is 6&#8243; in diameter, with 192 gear teeth around the edge;<\/li>\n\n\n\n<li>(paper diameter is 5\u00be&#8221;);<\/li>\n\n\n\n<li>each crank disc is 1&#8243; diameter (32 teeth), with the crank pin at \u215c&#8221; radius;<\/li>\n\n\n\n<li>the handle can only be turned clockwise. Consequently, the turntable can only turn anticlockwise;<\/li>\n\n\n\n<li>fixed pins at 90\u00b0 and 180\u00b0 are 6\u00bd&#8221; apart;<\/li>\n\n\n\n<li>distance between handle centre and fixed crank centre is 5&#8243; on a 7&#8243; PCD. Handle is therefore at ~225.585\u00b0 and fixed crank at ~134.415\u00b0<\/li>\n\n\n\n<li>the shift lever has a 10-70\u00b0 scale, which corresponds to moving the upper crank disc between 30-90\u00b0  of arc from the lower (fixed) crank disc;<\/li>\n\n\n\n<li>the pencil arms have 18 holes labelled A to R, at \u00bc&#8221; spacing from 5\u00be to 1\u00bd&#8221;. The perpendicular distance from the pivot holes to the pencil is 5\/16&#8243;. This small offset makes very little difference to the overall arm length.<\/li>\n<\/ul>\n\n\n\n<p>If we model the toy with a fixed turntable:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>the crank pins describe <a href=\"https:\/\/en.wikipedia.org\/wiki\/Epitrochoid\">epitrochoid<\/a>s around the edge of the paper;<\/li>\n\n\n\n<li>the pencil point traces the intersection of two circles of radius the lengths of the pencil arms, each centred on a crank pin.<\/li>\n<\/ul>\n\n\n\n<p>Here&#8217;s a very simple model in Python that emits a hard-coded (but editable) pattern in HP-GL: <a href=\"https:\/\/gist.github.com\/scruss\/529a8ad86ea4906cd7db999b285574d0\">Slightly imperfect Python simulation of the &#8220;HOOT-NANNY&#8221; (or Magic Designer) drawing toy<\/a> (static local copy: <a href=\"https:\/\/scruss.com\/wordpress\/wp-content\/uploads\/2022\/12\/hootnanny.zip\">hootnanny.zip<\/a>). It doesn&#8217;t do anything with the fixed circle studs (yet)<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Simulated (and not quite right yet) output from a &#8220;HOOT-NANNY&#8221; or Magic Designer, a proto-Spirograph toy that drew six-sided curves on round paper sheets. It was made by Howard B. Jones and Co. of Chicago, IL and first sold in 1929. The company&#8217;s better known for producing Jones Plugs and Sockets, sometimes known as Cinch-Jones [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[2],"tags":[3166,3307],"class_list":["post-16970","post","type-post","status-publish","format-standard","hentry","category-goatee-stroking-musing-or-something","tag-mathematics","tag-plot"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/pQNZZ-4pI","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/16970","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/comments?post=16970"}],"version-history":[{"count":6,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/16970\/revisions"}],"predecessor-version":[{"id":17790,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/posts\/16970\/revisions\/17790"}],"wp:attachment":[{"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/media?parent=16970"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/categories?post=16970"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/scruss.com\/blog\/wp-json\/wp\/v2\/tags?post=16970"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}