{"id":7,"date":"2007-09-03T22:41:43","date_gmt":"2007-09-04T02:41:43","guid":{"rendered":"http:\/\/www.logicalzero.com\/blog\/?p=7"},"modified":"2014-05-23T01:15:15","modified_gmt":"2014-05-23T05:15:15","slug":"the-motor-controller-project","status":"publish","type":"post","link":"http:\/\/www.logicalzero.com\/blog\/?p=7","title":{"rendered":"&#8216;The Motor Controller Project&#8217;"},"content":{"rendered":"<p>This project is actually sort of a sub-project; it will later be used to drive more interesting things.<\/p>\n<p>This is my first attempt at an L298 H-Bridge motor driver board. It is based primarily on some sample schematics from the L298 data sheet; some inspiration was also gleaned from other similar projects available on-line. This will also be my first attempt at etching a PC board, which is a little daunting.<\/p>\n<p>The design is fairly straightforward; it isn&#8217;t much more than a breakout board for the L298, plus the minimal handful of additional parts to support it. I&#8217;m going deliberately simple in order to keep it as generic as possible; I originally bought my L298 ICs with the intention of providing forward and reverse for a pair of standard DC motors, but it now looks like my first application will be driving a bipolar stepper motor.<\/p>\n<p><!--more--><a href=\"http:\/\/www.logicalzero.com\/blog\/images\/motorboard_schematic.png\" target=\"blank\"><img src=\"http:\/\/www.logicalzero.com\/blog\/images\/motorboard_schematic_thumb.png\" style=\"padding: 8px\" title=\"L298 H-Bridge board schematic v1.0 (click for larger image)\" alt=\"L298 H-Bridge board schematic\" align=\"middle\" \/><\/a><a href=\"http:\/\/www.logicalzero.com\/blog\/images\/motorboard_traces+placement.png\" target=\"blank\"><img src=\"http:\/\/www.logicalzero.com\/blog\/images\/motorboard_traces+placement_thumb.png\" style=\"padding: 8px\" title=\"L298 H-Bridge board layout v1.0 (click for larger image)\" alt=\"L298 H-Bridge board schematic\" align=\"middle\" \/><\/a><br clear=\"both\" \/><br \/>\nThe nonpolarized capacitors are .1\u00ce\u00bcF (-20\/+80%) 25V ceramic discs; the polarized one is a 1000\u00ce\u00bcF 35V electrolytic. The diodes are 1N5404 (3A, 400V) &#8212; ignore the fact that they are labeled 4004 in the schematic. I&#8217;m only planning to run at most 12V motors, so these values are probably overkill. Better safe than sorry &#8212; and aflame.<\/p>\n<p>I&#8217;m moderately happy with the layout, except the zig-zagging needed to accomodate the diodes. It looks kind of cool, but is more complex than I would like, especially for my first etched board. I could have adjusted the length of the diode&#8217;s leads on the top of the board, but EAGLE does not seem to be able to do that (or at least thoroughly obscures how to do it). I&#8217;m going to try to fix my <a href=\"http:\/\/www.finkproject.org\/\" target=\"_blank\">Fink<\/a> installation (which I sort-of broke, trying to port some other apps &#8216;by hand&#8217;) and use <a href=\"http:\/\/www.geda.seul.org\/\" target=\"_blank\">gEDA<\/a> from now on. Ignore the top-layer pads (the red rings) around the diodes and capacitors; those are just &#8216;notes&#8217; to myself. Since I&#8217;m going to etch this myself, I&#8217;m free to misuse symbols to my heart&#8217;s content.<\/p>\n<p>I picked up a standard-width industrial-grade Sharpie<sup>tm<\/sup> marker at the local stationery store and placed an order for an ultra-fine one. Everything I&#8217;ve seen suggests that these are exactly what electronics catalogs sell as a &#8216;etch-resist pen&#8217; for several times the price. The advertising text on the barrel states that the pen <em>&#8220;remains permanent under most chemical washes&#8221;<\/em>. I&#8217;m going to do some practice etching on scrap first, so I&#8217;ll put the pen through its paces at the same time.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>This project is actually sort of a sub-project; it will later be used to drive more interesting things. This is my first attempt at an L298 H-Bridge motor driver board. It is based primarily on some sample schematics from the L298 data sheet; some inspiration was also gleaned from other similar projects available on-line. This [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[6,5],"tags":[12],"_links":{"self":[{"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7"}],"collection":[{"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7"}],"version-history":[{"count":1,"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7\/revisions"}],"predecessor-version":[{"id":158,"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7\/revisions\/158"}],"wp:attachment":[{"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.logicalzero.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}