Slide from my talk at Linux Day 2013 in Avellino (Italy). Getting started with BeagleBone Black and Python library by Adafruit

1. HANDS ON EMBEDDED LINUX WITH
BEAGLEBONE BLACK
Daniele Costarella
Ex Carcere Borbonico (Avellino) – October 25th, 2013

2. October 25th, 2013
Linux Day 2013
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What is BeagleBone Black?
BeagleBone Black is a $45 MSRP community-supported development
platform for developers and hobbysts. Boot Linux in under 10 seconds
and get started on development in less than 5 minutes with just a single
USB cable.

3. October 25th, 2013
Hardware
Processor: AM335x 1GHz ARM® Cortex-A8
• 512MB DD3 RAM
• 2GB 8-bit eMMC on-board flash storage
• 3D graphics accelerator
Connectivity
• USB client for power and communications
• USB host
• Ethernet
• HDMI
• 2x46 pin headers
Software Compatibility
• Ångström Linux
• Android
• Cloud9 IDE on Node.js w/ BoneScript Library
and more…
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Embedded Linux for Makers
• Embedded Linux System blur the definition between
computer and device
• Powerful tools in the hands of “regular” people, not just those who
design electronics for a living
• More powerful and capable than a “simple” microcontroller like
ATMEGA 328 (Arduino)
• Perfect for those projects too complex to be executed on a MCU

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Advantages?
Built-in
networking
Remote
access
Timekeeping
Multitasking
Linux
software
Filesystem
Size
USB
Community

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Linux Day 2013
BeagleBone Black: Ready to use
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7. October 25th, 2013
Browsing Your BeagleBone
• Firstly, just test that the
connection is active by trying
to connect to the BBB with a
browser.
• Connect to the URL
http://192.168.7.2
• You should see a helful
introductory web page
served by the BeagleBoard
itself
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8. October 25th, 2013
Linux Day 2013
Go with SSH
• On Linux or Mac simply open a terminal window and
type the following command:
ssh 192.168.7.2 –l root
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9. October 25th, 2013
Using Python
Using GPIO, PWM and more with Python!
Available functionality:
• 7 Analog pins
• 65 Digital Pins at 3.3V
• 2xI2C
• 2xSPI
• 2x CAN Bus
• 4 Timers
• 4x UART
• 8x PWM
• A/D Converter
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10. October 25th, 2013
Expansion Headers
Each digital I/O pin has 8 different modes that can be selected, including GPIO
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11. October 25th, 2013
Linux Day 2013
Install Adafruit_BBIO
Commands needed to install the library.
Access via SSH and execute (on Angstrom Linux):
opkg update && opkg install python-pip python-setuptools python-smbus
pip install Adafruit_BBIO
You can test your installation simply trying to load one of
the modules:
import Adafruit_BBIO.GPIO as GPIO; print GPIO
#you should see this or similar:
<module 'Adafruit_BBIO.GPIO' from '/usr/local/lib/python2.7/dist-packages/
Adafruit_BBIO/GPIO.so'>
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Using the library
Open a Python console and import the library.
Example:
import Adafruit_BBIO.GPIO as GPIO
You can access the channels by either referencing the pin
“key” or the name.
import Adafruit_BBIO.GPIO as
GPIO
GPIO.setup("P8_10", GPIO.OUT)
GPIO.output("P8_10", GPIO.HIGH)
GPIO.setup("P8_14", GPIO.IN)
if GPIO.input("P8_14"):
print("HIGH")
else:
print("LOW")

13. October 25th, 2013
LED blinking: wiring
Positive to pin 10 and negative to GND
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14. October 25th, 2013
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LED blinking: writing the program
Back to the Linux/Mac prompt and create the executable
file
# nano blink.py
Write the simple program:
import Adafruit_BBIO.GPIO as GPIO
import time
GPIO.setup("P8_10", GPIO.OUT)
while True:
GPIO.output("P8_10", GPIO.HIGH)
time.sleep(0.5)
GPIO.output("P8_10", GPIO.LOW)
time.sleep(0.5)
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Linux Day 2013
LED blinking: writing the program
…and execute it
# python blink.py
Easy!
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Measuring Temperature: wiring
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Measuring Temperature
…and write the program
# nano temperature.py
Write the simple program:
import Adafruit_BBIO.ADC as ADC
import time
sensor_pin = 'P9_40'
ADC.setup()
while True:
reading = ADC.read(sensor_pin)
millivolts = reading * 1800 # 1.8V reference = 1800 mV
temp_c = (millivolts - 500) / 10
temp_f = (temp_c * 9/5) + 32
print('mv=%d C=%d F=%d' % (millivolts, temp_c, temp_f))
time.sleep(1)
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Using a Push Button
Energy Harvesting Demoboard
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19. October 25th, 2013
Writing the code
…and write the program
# nano button.py
Write the simple program:
import Adafruit_BBIO.GPIO as GPIO
import time
GPIO.setup("P8_12", GPIO.IN)
old_switch_state = 0
while True:
new_switch_state = GPIO.input("P8_12")
if new_switch_state == 1 and old_switch_state == 0 :
print('Do not press this button again!')
time.sleep(0.1)
old_switch_state = new_switch_state
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20. October 25th, 2013
Fade Effect with PWM: wiring
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21. October 25th, 2013
PWM?
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22. October 25th, 2013
Fade Effect with PWM: code
…and write the program
# nano led_fade.py
import Adafruit_BBIO.PWM as PWM
import time
led_pin = "P9_14"
PWM.start(led_pin, 0)
while True:
for i in range(0, 100):
PWM.set_duty_cycle(led_pin, i)
time.sleep(0.05)
for i in range(0, 100):
PWM.set_duty_cycle(led_pin, 100-i)
time.sleep(0.05)
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23. DEMO

24. October 25th, 2013
Linux Day 2013
Recommended readings
Getting Started with BeagleBone Black
Make
By Matt Richardson
Building Embedded Linux System
O’Reilly
By Karim Yaghmour, Jon Masters, Gilad Ben
Yassef, and Philippe Gerum
Embedded Linux System Design and
Development
By P. Raghavan, A. Lad, S. Neelakandan,
Auerbach
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25. October 25th, 2013
Linux Day 2013
Thank you
@dcostarella
danielecostarella.com
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