{"action":"created","issue":{"url":"https://api.github.com/repos/technobly/SparkCore-NeoPixel/issues/11","labels_url":"https://api.github.com/repos/technobly/SparkCore-NeoPixel/issues/11/labels{/name}","comments_url":"https://api.github.com/repos/technobly/SparkCore-NeoPixel/issues/11/comments","events_url":"https://api.github.com/repos/technobly/SparkCore-NeoPixel/issues/11/events","html_url":"https://github.com/technobly/SparkCore-NeoPixel/issues/11","id":88112809,"number":11,"title":"5V supply to the entire circuit","user":{"login":"omarojo","id":995265,"avatar_url":"https://avatars.githubusercontent.com/u/995265?v=3","gravatar_id":"","url":"https://api.github.com/users/omarojo","html_url":"https://github.com/omarojo","followers_url":"https://api.github.com/users/omarojo/followers","following_url":"https://api.github.com/users/omarojo/following{/other_user}","gists_url":"https://api.github.com/users/omarojo/gists{/gist_id}","starred_url":"https://api.github.com/users/omarojo/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/omarojo/subscriptions","organizations_url":"https://api.github.com/users/omarojo/orgs","repos_url":"https://api.github.com/users/omarojo/repos","events_url":"https://api.github.com/users/omarojo/events{/privacy}","received_events_url":"https://api.github.com/users/omarojo/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":3,"created_at":"2015-06-14T03:45:59Z","updated_at":"2015-06-15T16:15:07Z","closed_at":null,"body":"Cant I just use a 5v output power supply to power the SparkCore (into the VIN pin), and use the same 5v power supply to power the NeoPixels ? "},"comment":{"url":"https://api.github.com/repos/technobly/SparkCore-NeoPixel/issues/comments/112124298","html_url":"https://github.com/technobly/SparkCore-NeoPixel/issues/11#issuecomment-112124298","issue_url":"https://api.github.com/repos/technobly/SparkCore-NeoPixel/issues/11","id":112124298,"user":{"login":"technobly","id":2249224,"avatar_url":"https://avatars.githubusercontent.com/u/2249224?v=3","gravatar_id":"","url":"https://api.github.com/users/technobly","html_url":"https://github.com/technobly","followers_url":"https://api.github.com/users/technobly/followers","following_url":"https://api.github.com/users/technobly/following{/other_user}","gists_url":"https://api.github.com/users/technobly/gists{/gist_id}","starred_url":"https://api.github.com/users/technobly/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/technobly/subscriptions","organizations_url":"https://api.github.com/users/technobly/orgs","repos_url":"https://api.github.com/users/technobly/repos","events_url":"https://api.github.com/users/technobly/events{/privacy}","received_events_url":"https://api.github.com/users/technobly/received_events","type":"User","site_admin":false},"created_at":"2015-06-15T16:15:07Z","updated_at":"2015-06-15T16:15:07Z","body":"You need to make sure the RasperryPi can handle outputting that much current.  The Core draws about 150mA with Wi-Fi on, and each NeoPixel you light up with a 5V supply can consume 60mA if fully bright and WHITE.\r\n\r\nHere's a recommended hook up diagram: \r\n![](http://i.imgur.com/LGRR4CO.jpg)\r\n\r\nNeopixels can work fine powered off of 5V and data input 3.3V, generally I've seen this if you don't have a lot of them. If you are breadboarding, try it first... if you get a lot of glitching on the pixels then you probably need to level shift up to 5V.\r\n\r\nThat said, their datasheet does suggest a 0.7*VDD data input though:\r\nhttp://www.adafruit.com/datasheets/WS2812B.pdf\r\n\r\n...and because they must be powered at a minimum of 3.5V you shouldn't run them off of 3.3V (but I've run them all the way down to 2.6V and they work so YMMV).  A 4.2 - 3.6V LiPo will work ok, but you have to keep the data input high level above that 0.7*VDD.  So if the LiPo is 4.2 - 3.6V that's 2.94 - 2.52.  That should work just fine with a 3.3V data output from the Core or Photon.\r\n\r\nIf you run them off of 5.0V (RasPi), you need a minimum of a (5.0V*0.7 = 3.5V) data input... so this would be a perfect reason to level shift up to 5V with a single tri-state buffer such as this one:\r\nNL17SZ125XV5T2G if you making your own design, or this one [SN74HCT125N](http://www.digikey.com/product-detail/en/SN74HCT125N/296-8386-5-ND/3768600 if you are breadboarding."}}