{"id":1540,"date":"2019-04-14T20:01:02","date_gmt":"2019-04-14T19:01:02","guid":{"rendered":"https:\/\/ofalcao.pt\/blog\/?p=1540"},"modified":"2019-04-14T20:11:11","modified_gmt":"2019-04-14T19:11:11","slug":"voice-with-micropython-for-the-ev3","status":"publish","type":"post","link":"https:\/\/ofalcao.pt\/blog\/2019\/voice-with-micropython-for-the-ev3","title":{"rendered":"Voice with MicroPython for the EV3"},"content":{"rendered":"\n

The new MicroPython environment for the EV3 has sound commands… but not ‘speak’ like the full ev3dev python (ev3dev-lang-pyhton).<\/p>\n\n\n\n

But it has ‘os.system’ so we can make system calls…<\/p>\n\n\n\n

So <\/p>\n\n\n\n

#!\/usr\/bin\/env pybricks-micropython
import os
os.system('espeak \"hello\" --stdout | aplay')<\/pre>\n\n\n\n
works but as soon as we instantiate an ev3brick it stops working:<\/p>\n\n\n\n
#!\/usr\/bin\/env pybricks-micropython
from pybricks import ev3brick as brick
import os
os.system('espeak \"hello\" --stdout | aplay')<\/pre>\n\n\n\n
The error is ‘aplay: main:788: audio open error: Device or resource busy’<\/p>\n\n\n\n
So it seems pybricks allocates the ALSA sound card in some exclusive way. Strange because ‘aplay -L’ shows there is a software mixer:<\/p>\n\n\n\n
null
     Discard all samples (playback) or generate zero samples (capture)
 default:CARD=legoev3
     LEGO MINDSTORMS EV3 Speaker, LEGO MINDSTORMS EV3 Speaker
     Default Audio Device
 sysdefault:CARD=legoev3
     LEGO MINDSTORMS EV3 Speaker, LEGO MINDSTORMS EV3 Speaker
     Default Audio Device
 dmix:CARD=legoev3,DEV=0
     LEGO MINDSTORMS EV3 Speaker, LEGO MINDSTORMS EV3 Speaker
     Direct sample mixing device
 dsnoop:CARD=legoev3,DEV=0
     LEGO MINDSTORMS EV3 Speaker, LEGO MINDSTORMS EV3 Speaker
     Direct sample snooping device
 hw:CARD=legoev3,DEV=0
     LEGO MINDSTORMS EV3 Speaker, LEGO MINDSTORMS EV3 Speaker
     Direct hardware device without any conversions
 plughw:CARD=legoev3,DEV=0
     LEGO MINDSTORMS EV3 Speaker, LEGO MINDSTORMS EV3 Speaker
     Hardware device with all software conversions<\/pre>\n\n\n\n
So after several try&fail iteractions, I got a workaround by creating a ‘\/home\/robot\/.asoundrc’ file:<\/p>\n\n\n\n
pcm.hwmix {
     type dmix
     ipc_key 1939 # must be unique
     slave { pcm \"hw:CARD=legoev3\" }
 }
pcm.!default hwmix<\/pre>\n\n\n\n
This works… unless we also use ‘brick.sound.beep()’… then it locks in some other way. Oh well, nothing is perfect.<\/p>\n","protected":false},"excerpt":{"rendered":"
The new MicroPython environment for the EV3 has sound commands… but not ‘speak’ like the full ev3dev python (ev3dev-lang-pyhton). But it has ‘os.system’ so we can make system calls… So #!\/usr\/bin\/env pybricks-micropythonimport osos.system(‘espeak “hello” –stdout | aplay’) works but as soon as we instantiate an ev3brick it stops working: #!\/usr\/bin\/env pybricks-micropythonfrom pybricks import ev3brick as … Continuar a ler “Voice with MicroPython for the EV3”<\/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-1540","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-oQ","_links":{"self":[{"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/posts\/1540","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=1540"}],"version-history":[{"count":0,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/posts\/1540\/revisions"}],"wp:attachment":[{"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/media?parent=1540"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/categories?post=1540"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/tags?post=1540"},{"taxonomy":"series","embeddable":true,"href":"https:\/\/ofalcao.pt\/blog\/wp-json\/wp\/v2\/series?post=1540"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}