BreakfastSerial

A Firmata based framework for interacting with Arduinos over serial.

Arduino Setup

In order to use BreakfastSerial, you need to have an arduino running the standard firmata.

1. Download the Arduino IDE from the arduino website

• OSX
• Linux 32 bit
• Linux 64 bit
• Windows support coming soon.

2. Plug in your Arduino or Arduino compatible microcontroller via USB
3. Open the Arduino IDE, select: File > Examples > Firmata > StandardFirmata
4. Click the "Upload" button.

Installation

Using PyPi

pip install BreakfastSerial

From Source

git clone git://github.com/theycallmeswift/BreakfastSerial.git && cd BreakfastSerial

python setup.py install

Getting Started

The BreakfastSerial library provides a simple abstraction for a number of common components. Make sure your arduino is plugged in and is running firmata.

Arduino

If you create a Arduino object without any parameters, it will attempt to auto discover the serial port that the Arduino is attached to and connect automatically. Optionally, you can supply the path to a serial port (Ex. "/dev/tty.usbmodem4111").

from BreakfastSerial import Arduino
board = Arduino() # This will autodiscover the device

Blink an LED

To use the led object, import Led from BreakfastSerial. The constructor takes an Arduino object and a pin number as its arguments.

from BreakfastSerial import Arduino, Led
from time import sleep

board = Arduino()
pin = 13
led = Led(board, pin)

led.on()
sleep(2)
led.off()

You can also use the blink method and pass it a number of milliseconds to automate the blinking process

millis = 200
led.blink(millis)

Push a button

The Button component has a number of helper methods that make it easy to work with buttons. The constructor takes an Arduino object and a pin number as its arguments.

from BreakfastSerial import Button, Arduino

board = Arduino()
button = Button(board, 8)

def down_cb():
  print "button down"

def up_cb():
  print "button up"

def hold_cb():
  print "button held"

button.down(down_cb)
button.up(up_cb)
button.hold(hold_cb)

The down and up functions are just nice wrappers around the underlying event emitter. The Button component emits the following events:

• change - The button value changed
• down - The button is pressed
• up - The button is not being pressed
• hold - The button was held for at least 1 second

Use an RGB Led

The RGBLed component lets us change the colors of an RGB Led without having to interact with the three underlying leds.

from BreakfastSerial import Arduino, RGBLed
from time import sleep

board = Arduino()
led = RGBLed(board, { "red": 10, "green": 9, "blue": 8 })

led.red()
sleep(1)

led.green()
sleep(1)

led.blue()
sleep(1)

led.yellow()
sleep(1)

led.cyan()
sleep(1)

led.purple()
sleep(1)

led.white()
sleep(1)

led.off()

LED Brightness

You can set the brightness of an LED with the brightness function. The LED must be on a PWM capable pin or it will throw and error. Brightness is measured on a scale of 0% to 100%.

from BreakfastSerial import Arduino, Led
from time import sleep

board = Arduino()
pin = 9
led = Led(board, pin)

for x in range(0, 100):
  led.brightness(x)
  sleep(0.01)

Read a sensor

The Sensor component lets us read in data from a sensor (analog or digital). The constructor takes in an Arduino object and a pin number.

from BreakfastSerial import Arduino, Sensor

board = Arduino()
sensor = Sensor(board, "A0")

def print_value():
  print sensor.value

sensor.change(print_value)

The Sensor object has the following properties:

• threshold - the amount value must change by to trigger a change event (Default: 0.01)
• value - the value of the underlying pin

The change function is just a nice wrapper around the underlying event emitter. The Sensor component emits the following events:

• change - The sensor value change by at least the amount of threshold

Control a servo

The Servo component let's us control a servo. The constructor takes in an Arduino object and a pin number.

from BreakfastSerial import Arduino, Servo
from time import sleep

board = Arduino()
servo = Servo(board, "10")

servo.set_position(180)
sleep(2)
servo.move(-135)
sleep(2)
servo.center()
sleep(2)
servo.reset()

The value property of a Servo object is the current position of the servo in degrees

Control a DC Motor

The Motor component let's us control a DC Motor. The constructor takes in an Arduino object and a pin number. The motor must be on a PWM capable pin.

from BreakfastSerial import Arduino, Motor
from time import sleep

board = Arduino()
motor = Motor(board, 9)

motor.start(80)
sleep(2)
motor.speed = 50
sleep(2)
motor.stop()

The speed property is represented in a percentage of max speed. So, speed = 80 is setting the motor to 80% speed. Setting speed equal to 0 is the same as calling stop().

Moar!

There are a bunch of examples in the examples/ folder. Additional components will be added over time, so be sure to check back regularly.