Premiers pas avec BeagleBone Black

Démarrage
Connecter l'USB du BeagleBone Black. Une fois qu'il est visible (comme un disque : /media/BEAGLEBONE), on peut se connecter dessus : http://192.168.7.2

Des que cela fonctionne, on peut y aller par ssh (mot de passe vide) ssh root@192.168.7.2 Il n'y a pas de mot de passe. Par sécurité, mettre un mot de passe ou déployer une clé publique pour SSH.

Test des GPIO depuis le shell
Test des LED USR0123 cd /sys/class/leds ls _F cd beaglebone\:green\:usr0 ls -F cat trigger echo none > trigger echo oneshot > trigger echo heartbeat > trigger echo 1 > brightness echo 0 > brightness echo timer > trigger echo 100 > delay_on echo 900 > delay_off

Test des GPIO (write) cd /sys/class/gpio ls -F echo 60 > export cd gpio60 echo out > direction echo 1 > value cd .. echo 60 > unexport
 * 1) attach a LED at gpio1_28 (1*32+28=60) with a 220 ohms resistor

Test des GPIO (analog read) TBD

Test des GPIO (digital read) : mettre un bouton en pullup sur 60 9_28 ? (=1*32+28)
 * 1) !/bin/sh
 * 2) Read a GPIO input
 * 3) Author : http://wh1t3s.com/2009/05/14/reading-beagleboard-gpio/
 * 1) Author : http://wh1t3s.com/2009/05/14/reading-beagleboard-gpio/

GPIO=$1

cleanup { # Release the GPIO port echo $GPIO > /sys/class/gpio/unexport echo "" echo "" exit }

echo "$GPIO" > /sys/class/gpio/export echo "in" > /sys/class/gpio/gpio${GPIO}/direction
 * 1) Open the GPIO port

trap cleanup SIGINT # call cleanup on Ctrl-C

THIS_VALUE=`cat /sys/class/gpio/gpio${GPIO}/value` LAST_VALUE=$THIS_VALUE NEWLINE=0


 * 1) Read forever

while [ "1" = "1" ]; do # next three lines detect state transition if [ "$THIS_VALUE" != "$LAST_VALUE" ]; then EV="|" else EV="" fi

# "^" for high, '_' for low if [ "1" = "$THIS_VALUE" ]; then EV="${EV}^" else EV="${EV}_" fi echo -n $EV

# sleep for a while sleep 0.05

# wrap line every 72 samples LAST_VALUE=$THIS_VALUE THIS_VALUE=`cat /sys/class/gpio/gpio${GPIO}/value` NEWLINE=`expr $NEWLINE + 1` if [ "$NEWLINE" = "72" ]; then echo "" NEWLINE=0 fi

done

cleanup # call the cleanup routine

chmod 755 ./read_gpio.sh ./read_gpio.sh 60

Ressources

 * http://elinux.org/EBC_Exercise_02_Flashing_an_LED
 * http://www.armhf.com/index.php/using-beaglebone-black-gpios/
 * http://emmanuel.pouly.free.fr/beagle2.html
 * TI has more comprehensive information at: http://processors.wiki.ti.com/index.php/GPIO_Driver_Guide In particular, there's information that describes how to control the pin direction.

Test des GPIO en Python
import os import time def test(command): print command os.popen(command) test(“echo 60 > /sys/class/gpio/export”) test(“echo high > /sys/class/gpio/gpio60/direction”) test(“echo 1 > /sys/class/gpio/gpio60/value”) value = 1 for i in range(0,10): if value == 1: value = 0 else: value = 1 test(“echo ” + str(value) + ” > /sys/class/gpio/gpio60/value”) time.sleep(2) test(“echo 60 > /sys/class/gpio/unexport”)

Ressources

 * http://andrewatthewood.wordpress.com/2013/06/02/beaglebone-black-gpio-c-and-python/

Ressources

 * Bibliothèque C++ pour contrôler divers écrans LCD https://github.com/majestik666/Beagle_GPIO : vidéo de démo

Configuration Réseau
Sur le BeagleBone route add default gw 192.168.7.1

Mettre un DNS dans /etc/resolv.conf (par exemple : cat /etc/resolv.conf sur le PC, vous prenez la 1ère ligne "nameserver X.X.X.X" et vous la mettez dans /etc/resolv.conf sur le BeagleBone). nameserver 192.168.7.1 nameserver 8.8.8.8

Sur le PC qui sert de passerelle (celui où est connecté l'USB) : sudo iptables --append FORWARD --in-interface eth2 -j ACCEPT sudo iptables --table nat --append POSTROUTING --out-interface eth1 -j MASQUERADE

Note : sur ma machine, eth1 = l'I/F réseau du PC, et eth2 = la connexion filaire via USB (faire "ifconfig -a" pour vérifier, sinon adapter les commandes ci-dessus).

Vérifier que /proc/sys/net/ipv4/ip_forward contient "1". Sinon: sudo bash -c "echo 1 > /proc/sys/net/ipv4/ip_forward"

Et voilà... Depuis le BeagleBone, je peux pinger n'importe quelle adresse ping beaglebone.org ping 8.8.8.8 nslookup www.google.com

Configuration du temps
Attention : les mises à jour et les installations via npm requièrent une horloge mise à jour

voir http://derekmolloy.ie/automatically-setting-the-beaglebone-black-time-using-ntp/

date ntpdate -b -s -u pool.ntp.org date

Node.js
Attention : les mises à jour et les installations via npm requièrent une horloge mise à jour

Node.js est installé par défaut. Il sert le serveur web embarqué. La bibliothèque bonescript donne accès aux GPIO de la carte.

Led toggling
Copier ce code dans un fichier blinking.js pris dans le livre Bad to the Bone: Crafting Electronics Systems with BeagleBone and BeagleBone Black.

var b = require('bonescript');

//Old bonescript defines 'bone' globally var pins = (typeof bone != 'undefined') ? bone : b.bone.pins;

var ledPin = pins.P8_13; var ledPin2 = pins.USR3;

b.pinMode(ledPin, b.OUTPUT); b.pinMode(ledPin2, b.OUTPUT);

var state = b.LOW; b.digitalWrite(ledPin, state); b.digitalWrite(ledPin2, state);

setInterval(toggle, 1000);

function toggle { if(state == b.LOW) state = b.HIGH; else state = b.LOW; b.digitalWrite(ledPin, state); b.digitalWrite(ledPin2, state); }

node blinkled.js

Led on / off
Un autre exemple var led = process.argv[2]; var mode = process.argv[3];

var b = require('bonescript');

b.pinMode(led, b.OUTPUT);

if(mode == "ON") state = b.HIGH; else state = b.LOW;

b.digitalWrite(led, state);

node led.js USR0 ON node led.js USR1 OFF node led.js USR2 ON node led.js USR3 OFF

Analog read
Un autre exemple var b = require('bonescript'); var apin = process.argv[2]; b.analogRead(apin, printStatus); function printStatus(x) { console.log( x.value); }

node analogread.js P9_33 node analogread.js P9_35 node analogread.js P9_37 node analogread.js P9_39 node analogread.js P9_36 node analogread.js P9_38 node analogread.js P9_40

JDK
Télécharger le JDK d'Oracle : JDK 7 version "Linux ARM v6/v7 Soft Float ABI".

Le copier sur le Beagle via scp; exemple : scp jdk-7u45-linux-arm-vfp-sflt.tar.gz root@192.168.7.2:/home/root

Décompresser le tar.gz

export PATH=$PATH:/home/root/jdk1.7.0_45/bin export JAVA_HOME=/home/root/jdk1.7.0_45

java -version

Ajouter les 2 exports au .bashrc

OpenHAB
Télécharger OpenHAB

Le copier sur le Beagle via scp; exemple : scp openhab.tgz root@192.168.7.2:/home/root

Décompresser le tgz

cd openhab bin/start.sh

Naviguer sur http://192.168.7.2:8080/openhab.app?sitemap=demo

Il reste plus qu'à ajouter des règles avec le binding exec pour contrôler les GPIO du Beaglebone.

Liens:
 * http://tuxtec.blogspot.fr/2013/11/installing-openhab-on-beaglebone-black.html

Node-RED
Attention : les mises à jour et les installations via npm requièrent une horloge mise à jour

Voir http://nodered.org/docs/hardware/beagleboneblack.html

Charger et déployer ce flow pour faire clignoter les LED USR2 et USR3 du BBB [{"id":"b1fce44.9ce3c18","type":"inject","name":"on","topic":"","payload":"1","repeat":"","once":false,"x":127.16666412353516,"y":109.16666412353516,"wires":"b2a66e5e.6da6f"},{"id":"591aef4d.b55f38","type":"inject","name":"off","topic":"","payload":"0","repeat":"","once":false,"x":127.16666412353516,"y":149.16666412353516,"wires":"b2a66e5e.6da6f"},{"id":"36f2a960.164f76","type":"inject","name":"tick","topic":"","payload":"","repeat":"1","once":false,"x":127.16666412353516,"y":49.166664123535156,"wires":"7ee460bc.df48e"},{"id":"55249ec9.21e61","type":"debug","name":"","active":true,"x":567.1666641235352,"y":89.16666412353516,"wires":[]},{"id":"7ee460bc.df48e","type":"function","name":"Toggle USR3 LED on input","func":"\nvar pin = \"USR3\"\nvar b = context.global.bonescript;\ncontext.state = context.state || b.LOW;\n\nb.pinMode(pin, b.OUTPUT);\n\n(context.state == b.LOW) ? context.state = b.HIGH : context.state = b.LOW;\nb.digitalWrite(pin, context.state);\n\nreturn msg;","outputs":1,"x":347.16666412353516,"y":69.16666412353516,"wires":"55249ec9.21e61"},{"id":"b2a66e5e.6da6f","type":"function","name":"Set USR2 LED on input","func":"\nvar pin = \"USR2\";\nvar b = context.global.bonescript;\n\nb.pinMode(pin, b.OUTPUT);\n\nvar level = (msg.payload === \"1\")?1:0;\nb.digitalWrite(pin, level);\n\nreturn msg;","outputs":1,"x":347.16666412353516,"y":129.16666412353516,"wires":"55249ec9.21e61"}]

http://nodered.org/docs/hardware/arduino.html Charger et déployer ce flow pour faire clignoter la LED 13 de l'Arduino branché sur le port USB du BBB npm install firmata

Le port est /dev/ttyACM0 [{"id":"d7663aaf.47194","type":"arduino-board","repeat":"25","device":"/dev/ttyACM0"},{"id":"8c09ca6c.a975d","type":"arduino out","name":"","pin":"13","state":"OUTPUT","arduino":"d7663aaf.47194","x":509.16667556762695,"y":162.16666984558105,"wires":[]},{"id":"e37b6a97.610968","type":"inject","name":"tick","topic":"","payload":"","repeat":"0.5","once":false,"x":116.16668319702148,"y":62.16666507720947,"wires":"60b4aeaa.800d58"},{"id":"60b4aeaa.800d58","type":"function","name":"Toggle output on input","func":"\n// initialise level as a context variable if currently undefined \n// (context variables persist between calls to the function)\ncontext.level = context.level || false;\n\n// if it's a 0 make it a 1 else make it a 0...\ncontext.level = !context.level;\n\n// set the payload to the level and return\nmsg.payload = context.level;\nreturn msg;","outputs":1,"x":298.1666793823242,"y":113.16665458679199,"wires":"8c09ca6c.a975d"}]

Arduino
Attention : les mises à jour et les installations via npm requièrent une horloge mise à jour

avec Firmata et Node.js : TBD avec Node.js

Le port de l'Arduino est /dev/ttyACM0

http://www.instructables.com/id/How-to-make-a-BeagleBone-and-an-Arduino-communicat/

Future carte Arduino TRE : http://beagleboard.org/blog/2013-10-03-beagleboardorg-collaborates-with-arduino/

XBMC

 * http://beagleboard.org/project/xbmc/

OpenCV

 * http://emmanuel.pouly.free.fr/beagle5.html

GStreamer

 * http://www.oz9aec.net/index.php/beaglebone/476-turning-the-beaglebone-into-a-high-definition-ip-camera

MQTT

 * http://www.eclipse.org/paho/TalkingSmall.html

En Python avec Paho Python import time

import Adafruit_BBIO.ADC as ADC

import paho.mqtt.client as mqtt

sensor_pin = 'P9_40'

ADC.setup

mqttc = mqtt.Client

mqttc.connect("m2m.eclipse.org", 1883, 60)

mqttc.loop_start

while True:

reading = ADC.read(sensor_pin)

millivolts = reading * 1800 # 1.8V reference = 1800 mV

temp_c = (millivolts - 500) / 10

print('mv=%.2f C=%.2f' % (millivolts, temp_c))

mqttc.publish("bbbexample/tmp36/mv","%.2f" % millivolts);

mqttc.publish("bbbexample/tmp36/c","%.2f" % temp_c);

time.sleep(1)[a]

BBB contrôlant Dagu Wild Thumper 6WD Chassis
TBD
 * Dagu Wild Thumper 6WD Chassis
 * Monster Moto Shield (+ peut être Arduino)
 * Webcam Logitech C270
 * Clé Wifi
 * Mini-USB Hub