{"id":1833,"date":"2017-05-07T14:33:17","date_gmt":"2017-05-07T13:33:17","guid":{"rendered":"https:\/\/www.nathankowald.com\/blog\/?p=1833"},"modified":"2017-05-07T14:34:36","modified_gmt":"2017-05-07T13:34:36","slug":"raspberry-pi-prepaid-energy-monitor","status":"publish","type":"post","link":"https:\/\/www.nathankowald.com\/blog\/2017\/05\/raspberry-pi-prepaid-energy-monitor\/","title":{"rendered":"Prepaid energy monitor with a Raspberry Pi"},"content":{"rendered":"<h4>Instructions: <a href=\"https:\/\/github.com\/n8kowald\/powerpi\" target=\"_blank\" rel=\"nofollow noopener\">https:\/\/github.com\/n8kowald\/powerpi<\/a><\/h4>\n<p>My flat has a prepayment energy meter.<br \/>\nSometimes I forget to check how much money we have and the power goes out, forcing me to walk to the nearest open PayPoint location at inconvenient times.<\/p>\n<p>I wanted a way to automate these checks.<\/p>\n<div id=\"attachment_1835\" style=\"width: 1560px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1835\" src=\"https:\/\/www.nathankowald.com\/blog\/wp-content\/uploads\/2017\/05\/powerpi.jpg\" alt=\"\" width=\"1550\" height=\"793\" class=\"size-full wp-image-1835\" \/><p id=\"caption-attachment-1835\" class=\"wp-caption-text\">The Raspberry Pi B+ enclosed emails me a photo of the money we have left<\/p><\/div>\n<p>I had an unused Raspberry Pi B+, camera module (REV 1.3), and a USB Wi-Fi dongle. With these I could take a photo of the amount left and email myself a photo every day at a specified time.<\/p>\n<p>It turned out to be easy.<br \/>\nThe most time consuming bit was experimenting with <a href=\"https:\/\/www.raspberrypi.org\/documentation\/usage\/camera\/raspicam\/raspistill.md\" target=\"_blank\">raspistill<\/a> options to produce the best photo for the dark cabinet it&#8217;s enclosed in.<\/p>\n<div id=\"attachment_1843\" style=\"width: 660px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-1843\" src=\"https:\/\/www.nathankowald.com\/blog\/wp-content\/uploads\/2017\/05\/power-left-1.jpg\" alt=\"Amount of money left on our prepaid electricity meter\" width=\"650\" height=\"450\" class=\"size-full wp-image-1843\" \/><p id=\"caption-attachment-1843\" class=\"wp-caption-text\">Amount of money left on our prepaid electricity meter<\/p><\/div>\n<p>As you can see the photo is not amazing. However, considering it was taken in a dark cabinet I&#8217;m happy with the result.<\/p>\n<h4>Full instructions here: <a href=\"https:\/\/github.com\/n8kowald\/powerpi\" target=\"_blank\" rel=\"nofollow noopener\">https:\/\/github.com\/n8kowald\/powerpi<\/a><\/h4>\n<p>Next, I want to use Optical Character Recognition (OCR) to detect the amount in the photo.<br \/>\nI could then take readings every 5 minutes, save that to a database and produce a graph of the times when we use the most electricity.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Instructions: https:\/\/github.com\/n8kowald\/powerpi My flat has a prepayment energy meter. Sometimes I forget to check how much money we have and the power goes out, forcing me to walk to the nearest open PayPoint location at inconvenient times. I wanted a way to automate these checks. I had an unused Raspberry Pi B+, camera module (REV [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[25],"tags":[],"class_list":["post-1833","post","type-post","status-publish","format-standard","hentry","category-raspberry-pi"],"acf":[],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/posts\/1833","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/comments?post=1833"}],"version-history":[{"count":29,"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/posts\/1833\/revisions"}],"predecessor-version":[{"id":1865,"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/posts\/1833\/revisions\/1865"}],"wp:attachment":[{"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/media?parent=1833"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/categories?post=1833"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.nathankowald.com\/blog\/wp-json\/wp\/v2\/tags?post=1833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}