{"id":90,"date":"2017-06-05T20:38:05","date_gmt":"2017-06-05T19:38:05","guid":{"rendered":"http:\/\/www.burningimage.net\/cattrack\/?p=90"},"modified":"2017-07-19T20:59:18","modified_gmt":"2017-07-19T19:59:18","slug":"first-design-thoughts","status":"publish","type":"post","link":"https:\/\/www.burningimage.net\/cattrack\/first-design-thoughts\/","title":{"rendered":"First Design Thoughts"},"content":{"rendered":"

I’ve pretty much ruled out any kind of design that requires a continuous connection via cellular modem.<\/strong><\/p>\n

The advantage of a continuous cellular connection is\u00a0that I would be able to remotely send a query to the collar (either via SMS or a data connection) and get it to report its location back to me, from anywhere in the world.<\/p>\n

<\/p>\n

Sounds really cool, but unfortunately you could only ever get a battery life measured in days out of such a design, at least without designing a trailer full of batteries for Buttons to tow along behind him. \u00a0This is why the pawtrack collar (discussed here<\/a>) only lasts for 2-3 days. \u00a0I want months, not days!<\/p>\n

In order to get months rather than days, I need the collar to spend the vast majority of its time in a really deep-sleep mode. \u00a0Assuming I manage to design-in a 200 mAh battery, then in order to get a 90\u00a0day\u00a0battery life I’d need to make sure that I consume an average of no more than 93\u00a0\u00b5A (that’s 93 millionths of an Amp!). \u00a0That’s over 100 times lower power than a typical LED!<\/p>\n

I reckon that the way to achieve this ultra-low power consumption is going to be to\u00a0design a tracker which works\u00a0in a similar way to devices like tile<\/a>.\u00a0 This uses Bluetooth Low Energy (BLE) to allow you to communicate with the\u00a0tile device from your phone. \u00a0Because of the nature of the BLE protocol, the coin cell battery in a tile can last for a year.<\/p>\n

I could certainly design a tracker to use BLE, just like the tile, but the problem with BLE is that the range is pretty limited. \u00a0You’re never going to get over 100 feet range, even across a completely empty field! \u00a0Not ideal for a cat tracker.<\/p>\n

All I need to do is design a device that sacrifices some of the 1 year battery life of the tile to give us some extra range, hopefully up to around a\u00a0mile radius from wherever I’m stood. \u00a0Unless something’s gone really wrong then that hopefully means I’ll be able to find Buttons whilst sat in my lounge.<\/p>\n

I reckon the way to do this is with a narrow-band RF design. \u00a0I think I could have the collar sit in a really low power receive mode, with the GPS module powered off. \u00a0I would then send a narrow-band RF message to the collar from a base unit, instructing the collar to wake up and turn on the GPS receiver. \u00a0As soon as it gets a GPS lock it’ll transmit the position back to the base unit.<\/p>\n

A\u00a0range of 1 mile and a battery life of 3 months would be perfect for me. \u00a0Obviously the battery life would decrease each time you instructed the collar to wake up and transmit back its position, but given that it’s primarily a device to find your cat when it’s lost, I reckon this is fine.<\/p>\n

So, onto looking for some suitable components to try and achieve this..!<\/p>\n","protected":false},"excerpt":{"rendered":"

I’ve pretty much ruled out any kind of design that requires a continuous connection via cellular modem. The advantage of a continuous cellular connection is\u00a0that I would be able to remotely send a query to the collar (either via SMS or a data connection) and get it to report its location back to me, from […]<\/p>\n","protected":false},"author":1,"featured_media":94,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[45,17,6,50,48,8,49,47,51,46,7],"class_list":["post-90","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-posts","tag-cellular","tag-gps","tag-narrowband","tag-pawtrack","tag-range","tag-receiver","tag-rf","tag-sms","tag-tile","tag-tracker","tag-transmitter"],"_links":{"self":[{"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/posts\/90","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/comments?post=90"}],"version-history":[{"count":7,"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/posts\/90\/revisions"}],"predecessor-version":[{"id":119,"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/posts\/90\/revisions\/119"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/media\/94"}],"wp:attachment":[{"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/media?parent=90"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/categories?post=90"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.burningimage.net\/cattrack\/wp-json\/wp\/v2\/tags?post=90"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}