{"id":960,"date":"2016-09-08T15:40:59","date_gmt":"2016-09-08T14:40:59","guid":{"rendered":"http:\/\/ofalcao.pt\/blog\/?p=960"},"modified":"2016-09-08T15:40:59","modified_gmt":"2016-09-08T14:40:59","slug":"lego-wedo-2-0-with-mit-app-inventor","status":"publish","type":"post","link":"https:\/\/ofalcao.pt\/blog\/2016\/lego-wedo-2-0-with-mit-app-inventor","title":{"rendered":"LEGO WeDo 2.0 with MIT App Inventor"},"content":{"rendered":"

I got a request for help today, Mr. Rocha is trying to use MIT App Inventor to control the WeDo 2.0 Smart Hub RGB LED.<\/p>\n

I’ve never used App Inventor<\/a> before but I had already installed the Companion once in my Android Phone because I read something somewhere and found it quite similar to Snap! and Scratch (and\u00a0 also just because it is from MIT… I have a fetiche for MIT back from when I was at college and read Nicholas Negroponte<\/a> articles on Wired). So let’s give it a try.<\/p>\n

I just wanted to connect to the WeDo 2.0 Smart Hub and change the color to RED. When using gatttool that’s done with just<\/p>\n

char-write-cmd 3d 06040109<\/pre>\n
Just needed to add the BLE extension<\/a> to start working, getting a connection was easy but writing to the handle took a while since App Inventor BLE extension doesn’t use handles, just UUIDs. So I had to go back to my notes and find the Service UUID and the Characteristic UUID:<\/p>\n
service_uuid = 00004f0e-1212-efde-1523-785feabcd123\r\ncharacteristic_uuid = 00001565-1212-efde-1523-785feabcd123<\/pre>\n
Then I tried a block called “call BluetoothLE. WriteStringValue” but I couldn’t find a way to convert an hexadecimal string (“06040109”) to a proper string to send.<\/p>\n
So I tried another block, “call BluetoothLE.WriteIntValue”. At first I made an old mistake, converting “06040109h” to “100925705”. Didn’t work.<\/p>\n
Then I wrote it in reverse (“09010406h”) and converted it to “151061510”. And now it works!<\/p>\n
\"WeDoLED\"<\/a><\/p>\n
Now that I finally started, I think I will use App Inventor some more times. Damn easy to create an BLE Android app!<\/p>\n","protected":false},"excerpt":{"rendered":"
I got a request for help today, Mr. Rocha is trying to use MIT App Inventor to control the WeDo 2.0 Smart Hub RGB LED. I’ve never used App Inventor before but I had already installed the Companion once in my Android Phone because I read something somewhere and found it quite similar to Snap! … Continuar a ler “LEGO WeDo 2.0 with MIT App Inventor”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[1],"tags":[],"series":[],"class_list":["post-960","post","type-post","status-publish","format-standard","hentry","category-sem-categoria"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2Mhyv-fu","_links":{"self":[{"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/posts\/960","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/comments?post=960"}],"version-history":[{"count":0,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/posts\/960\/revisions"}],"wp:attachment":[{"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/media?parent=960"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/categories?post=960"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/tags?post=960"},{"taxonomy":"series","embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/series?post=960"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}