{"id":41,"date":"2018-09-11T18:26:25","date_gmt":"2018-09-11T22:26:25","guid":{"rendered":"http:\/\/raucousatthecaucus.com\/?p=41"},"modified":"2018-09-11T18:26:25","modified_gmt":"2018-09-11T22:26:25","slug":"update-on-the-exposure-meter","status":"publish","type":"post","link":"https:\/\/blog.raucousatthecaucus.net\/index.php\/2018\/09\/11\/update-on-the-exposure-meter\/","title":{"rendered":"Update on the exposure meter"},"content":{"rendered":"\n<p>The parts for the exposure meter came in last week. It seems that everything works just fine, except for the breadboard I picked out of the pack of 3 I ordered. It seems like the lower half of it does not work. Hopefully the other two are better.<\/p>\n\n\n\n<p>Anyways, these are the major parts in the system:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li><a href=\"https:\/\/www.adafruit.com\/product\/2590\">Adafruit Mini Metro<\/a>. This is an Arduino-compatible, ATmega328-based microcontroller. It&#8217;s the brain that processes the input from buttons and the light sensor and displays everything on the display.<\/li><li><a href=\"https:\/\/www.adafruit.com\/product\/938\">128&#215;64 OLED display<\/a>. This seemed like a good choice for this project because the OLED displays are easy to read in bright light, and I&#8217;ll be using this thing outside most of the time.<\/li><li><a href=\"https:\/\/www.adafruit.com\/product\/1980\">TSL2591 light sensor<\/a>. This senses the light and gives the microcontroller somewhere to start when deciding what shutter speed or aperture to suggest.<\/li><\/ul>\n\n\n\n<p>So far, I have a set up that does the following:<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Reads the light sensor and returns a value in lux.<\/li><li>Plugs the lux reading into an equation to get an <a href=\"https:\/\/en.wikipedia.org\/wiki\/Exposure_value\">exposure value<\/a>.<\/li><li>Plugs that exposure value into one of two equations:<ul><li>One equation finds a shutter speed that works with a selected aperture.<\/li><li>The other equation finds an aperture that works with a selected shutter speed.<\/li><\/ul><\/li><li>Sends the lux reading, exposure value, selected ISO, and the computed shutter speed or aperture to the display.<\/li><\/ul>\n\n\n\n<p>Now I need to create a menu system for adjusting a few settings, such as the ISO, changing the mode from shutter speed to aperture and perhaps setting a minimum shutter speed or aperture value. I also need to come up with a way for the results from these equations to get rounded to the nearest third of a stop so they&#8217;re easier to use. That might be the trickiest part, but I guess I&#8217;ll come up with something.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The parts for the exposure meter came in last week. It seems that everything works just fine, except for the breadboard I picked out of the pack of 3 I ordered. It seems like the lower half of it does not work. Hopefully the other two are better. Anyways, these are the major parts in &hellip; <a href=\"https:\/\/blog.raucousatthecaucus.net\/index.php\/2018\/09\/11\/update-on-the-exposure-meter\/\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Update on the exposure meter&#8221;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[21],"tags":[],"class_list":["post-41","post","type-post","status-publish","format-standard","hentry","category-buildingthings"],"_links":{"self":[{"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/posts\/41","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/comments?post=41"}],"version-history":[{"count":0,"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/posts\/41\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/media?parent=41"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/categories?post=41"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.raucousatthecaucus.net\/index.php\/wp-json\/wp\/v2\/tags?post=41"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}