{"id":330,"date":"2010-02-28T23:54:59","date_gmt":"2010-03-01T03:54:59","guid":{"rendered":"http:\/\/designforpeople.ca\/?p=330"},"modified":"2010-03-01T00:06:11","modified_gmt":"2010-03-01T04:06:11","slug":"multiplexing-with-iv-18","status":"publish","type":"post","link":"http:\/\/designforpeople.ca\/?p=330","title":{"rendered":"Multiplexing with IV-18"},"content":{"rendered":"<p>What makes it possible for an amateur like me to take on a project like this is the overwhelming amount of support that comes from a worldwide community of developers, often without their knowledge. For example, the circuit design and firmware for the <a href=\"http:\/\/www.ladyada.net\/make\/icetube\/\" target=\"_blank\">icetube clock<\/a> are freely available to download and re-use under an open-source licence. The clock design is similar in some ways to my own. The schematics and code don&#8217;t have everything I&#8217;ll need in the final design, but\u00a0I have learned a great deal and saved hours, days, maybe weeks worth of time in procurement and experimentation, and this\u00a0gave me a great tutorial for developing my own design.<\/p>\n<p>I was able to light up the IV-18 tube and have it display digits, without completely understanding how it all works. I guess this is the real beauty of open-source. You don&#8217;t have to know everything, you don&#8217;t have to do everything. You find something and build on it, and bring your own contribution.<\/p>\n<p>For this prototype I am using an obsolete\u00a0<a href=\"http:\/\/pdf1.alldatasheet.com\/datasheet-pdf\/view\/25838\/SUTEX\/HV518P\/+QF7F8uxRRDVapXYADU+\/datasheet.pdf\" target=\"_blank\">HV518P<\/a> high-voltage driver IC, which takes signals from the microcontroller and outputs high-voltage directly to the display segments in the VFD tube. I chose this one mainly because it comes in a DIP package, so I can fit it into a breadboard.<\/p>\n<p>The most difficult part of getting all this to work was wiring from the driver to the VFD tube. The schematics for the icetube were for the popular <a href=\"http:\/\/datasheets.maxim-ic.com\/en\/ds\/MAX6921-MAX6931.pdf\" target=\"_blank\">MAX6921<\/a> driver, which I will likely use in the final design, but the wiring for the HV518 seems to be a bit different &#8211; so I had to cross-reference the icetube schematic and the data sheet for the HV518 to know which pins went where, which didn&#8217;t seem to work so well. It can be a bit like a rubix cube &#8211; even if it&#8217;s off by just one bit, it can take hundreds of re-tries to get it all in order. In the end I got it working by sheer brute force and determination.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-331\" title=\"img_1007\" src=\"http:\/\/designforpeople.ca\/wp-content\/uploads\/2010\/02\/img_1007-200x300.jpg\" alt=\"img_1007\" width=\"200\" height=\"300\" srcset=\"http:\/\/designforpeople.ca\/wp-content\/uploads\/2010\/02\/img_1007-200x300.jpg 200w, http:\/\/designforpeople.ca\/wp-content\/uploads\/2010\/02\/img_1007-682x1024.jpg 682w, http:\/\/designforpeople.ca\/wp-content\/uploads\/2010\/02\/img_1007.jpg 2048w\" sizes=\"(max-width: 200px) 100vw, 200px\" \/><\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-332 alignnone\" title=\"img_1019\" src=\"http:\/\/designforpeople.ca\/wp-content\/uploads\/2010\/02\/img_1019-300x200.jpg\" alt=\"img_1019\" width=\"300\" height=\"200\" srcset=\"http:\/\/designforpeople.ca\/wp-content\/uploads\/2010\/02\/img_1019-300x200.jpg 300w, http:\/\/designforpeople.ca\/wp-content\/uploads\/2010\/02\/img_1019-1024x682.jpg 1024w\" sizes=\"(max-width: 300px) 100vw, 300px\" \/><\/p>\n","protected":false},"excerpt":{"rendered":"<p>What makes it possible for an amateur like me to take on a project like this is the overwhelming amount of support that comes from a worldwide community of developers, often without their knowledge. For example, the circuit design and firmware for the icetube clock are freely available to download and re-use under an open-source [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3,17],"tags":[],"_links":{"self":[{"href":"http:\/\/designforpeople.ca\/index.php?rest_route=\/wp\/v2\/posts\/330"}],"collection":[{"href":"http:\/\/designforpeople.ca\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/designforpeople.ca\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/designforpeople.ca\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/designforpeople.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=330"}],"version-history":[{"count":6,"href":"http:\/\/designforpeople.ca\/index.php?rest_route=\/wp\/v2\/posts\/330\/revisions"}],"predecessor-version":[{"id":334,"href":"http:\/\/designforpeople.ca\/index.php?rest_route=\/wp\/v2\/posts\/330\/revisions\/334"}],"wp:attachment":[{"href":"http:\/\/designforpeople.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=330"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/designforpeople.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=330"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/designforpeople.ca\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=330"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}