{"id":501,"date":"2014-08-10T21:30:17","date_gmt":"2014-08-10T20:30:17","guid":{"rendered":"http:\/\/ofalcao.pt\/blog\/?p=501"},"modified":"2014-08-10T21:30:17","modified_gmt":"2014-08-10T20:30:17","slug":"ev3dev-controlando-motores","status":"publish","type":"post","link":"https:\/\/ofalcao.pt\/blog\/2014\/ev3dev-controlando-motores","title":{"rendered":"ev3dev – controlando motores"},"content":{"rendered":"

A utiliza\u00e7\u00e3o b\u00e1sica do LEGO Mindstorms EV3 com ev3dev fica completa com a utiliza\u00e7\u00e3o de motores.<\/p>\n

Ligando um motor (45503<\/a> EV3 Medium Servo Motor) na ficha A, o sistema operativo acusa o evento:<\/p>\n

root@ev3dev:~# dmesg\n(...)\ntacho-motor tacho-motor0: Tacho motor registered.\nev3-tacho-motor outA:motor: A Tacho Motor connected to port outA gpio 91 irq 192\n\n<\/pre>\n
Uma vez mais \u00e9 necess\u00e1rio consultar a wiki do projecto ev3dev<\/a> para entender como aceder aos motores. Estes tamb\u00e9m s\u00e3o mapeados pelo sistema operativo, desta vez em “\/sys\/bus\/legoev3\/devices\/” e em ” \/sys\/class\/tacho-motor\/”:<\/p>\n
root@ev3dev:~# ls \/sys\/bus\/legoev3\/devices\/\nin2\u00a0 in3\u00a0 in4\u00a0 outA\u00a0 outA:motor\u00a0 outB\u00a0 outC\u00a0 outD<\/pre>\n
root@ev3dev:~# ls \/sys\/class\/tacho-motor\/\ntacho-motor0<\/pre>\n
root@ev3dev:~# ls \/sys\/class\/tacho-motor\/tacho-motor0\ndevice\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 port_name\u00a0\u00a0\u00a0\u00a0\u00a0 pulses_per_second\u00a0\u00a0\u00a0\u00a0 reset\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0speed_regulation_K\u00a0 subsystem\nduty_cycle\u00a0\u00a0\u00a0\u00a0 position\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 pulses_per_second_sp\u00a0 run\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0speed_regulation_P\u00a0 time_sp\nduty_cycle_sp\u00a0 position_mode\u00a0 ramp_down_sp\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 run_mode\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0state\u00a0\u00a0 \u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 type\nestop\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 position_sp\u00a0\u00a0\u00a0 ramp_up_sp\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 speed_regulation_D\u00a0\u00a0 \u00a0stop_mode\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 uevent\npolarity_mode\u00a0 power\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 regulation_mode\u00a0\u00a0 \u00a0\u00a0\u00a0\u00a0 speed_regulation_I\u00a0\u00a0 \u00a0stop_modes<\/pre>\n
Muito informa\u00e7\u00e3o para processar mas para come\u00e7ar podemos confirmar apenas o tipo de motor:<\/p>\n
root@ev3dev:~# cat \/sys\/class\/tacho-motor\/tacho-motor0\/type\nminitacho<\/pre>\n
Os motores Mindstorms s\u00e3o inicializados no modo “run forever”, podemos tamb\u00e9m confirmar isso:<\/p>\n
root@ev3dev:~# cat \/sys\/class\/tacho-motor\/tacho-motor0\/run_mode\nforever<\/pre>\n
Neste modo podemos controlar o motor controlando 2 par\u00e2metros:<\/p>\n
    \n
  • \/sys\/class\/tacho-motor\/tacho-motor0\/duty_cycle_sp<\/li>\n
  • \/sys\/class\/tacho-motor\/tacho-motor0\/run<\/li>\n<\/ul>\n
    o shell script abaixo faz o motor rodar 5 segundos num sentido e 5 segundos no sentido inverso, com um duty factor de 50%:<\/p>\n
     #!\/bin\/bash\n echo\u00a0\u00a0 0 > \/sys\/class\/tacho-motor\/tacho-motor0\/duty_cycle_sp\n echo\u00a0\u00a0 1 > \/sys\/class\/tacho-motor\/tacho-motor0\/run\n echo\u00a0\u00a0 50 > \/sys\/class\/tacho-motor\/tacho-motor0\/duty_cycle_sp\n sleep 5s\n echo\u00a0\u00a0 0 > \/sys\/class\/tacho-motor\/tacho-motor0\/duty_cycle_sp\n sleep 1s\n echo\u00a0\u00a0 -50 > \/sys\/class\/tacho-motor\/tacho-motor0\/duty_cycle_sp\n sleep 5s\n echo\u00a0\u00a0 0 > \/sys\/class\/tacho-motor\/tacho-motor0\/duty_cycle_sp\n echo\u00a0\u00a0 0 > \/sys\/class\/tacho-motor\/tacho-motor0\/run<\/pre>\n