Raspberry Pi Home Automation Project: Remote Power Plug Socket Control

From hacking dash buttons it is a small step towards further home automation. Home automation in the sense of remotely controlling power plug sockets. This way a dash button can be used as an additional light switch.
The ingredients for such a project are

Raspberry Pi (Zero W)
Amazon Dash Button
433 MHz receiver and transmitter
Remote controlled power plug sockets (ideally with DIP switches)

Software

On the Raspberry Pi the following libraries are required at least:

sudo pip3 install rpi-rf     # https://github.com/milaq/rpi-rf
sudo pip3 install scapy-python3   # https://github.com/phaethon/scapy

Setup

433MHz Receiver

Pi (Zero W) 433 MHz Receiver
GND GND
3,3 V 3,3 V
GPIO 27 Data

433MHz Transmitter

Pi (Zero W) 433 MHz Transmitter
GND GND
3,3 V 3,3 V
GPIO 17 Data

Power Plug Sockets

To set up the power plug sockets see their manual. The ones with DIP switches should be preferred over those without. DIP switches allow to precisely select the addresses of the power plug sockets.

Preparations

First the codes to toggle the power plug sockets are required. These can be read using the example script from  the rpi-rf library.

sudo python3 rcv.py

Make a note of the codes for turning the power on and for turning the power off for each power plug socket. The codes have to be adapted in the python script below. Required is also the MAC adress of the Dash Button to be used as an additional light switch.

from scapy.all import *
import http.client, urllib
from rpi_rf import RFDevice

from time import sleep

#A on : 1234567 A off: 9876543

fileLRL="/home/pi/state.txt"

rfdevice = RFDevice(17)
rfdevice.enable_tx()
protocol = 1
pulselength = 350

def readFile(fileName):
  state=0
  try:
    target = open(fileName, 'r')
    state = target.read()
    target.close()
    print("Read toggle state: " + str(state))
  except FileNotFoundError:
    writeFile(fileName, state)
  return state

def writeFile(fileName, state):
  print("Store toggle state: " + str(state))
  target = open(fileName, 'w')
  target.write(str(state))
  target.close()
  return True

def toggleLight():
  state = readFile(fileLRL)
  print("LRL state " + str(state))
  if state == str(0):
    print ("light is currently off, turn it on")
    rfdevice.tx_code(1234567, protocol, pulselength)
    writeFile(fileLRL, 1)
  else:
    print ("light is currently on, turn it off")
    rfdevice.tx_code(9876543, protocol, pulselength)
    writeFile(fileLRL, 0)

def arp_detect(pkt):
  if pkt[ARP].op == 1: # network request
    mac = pkt[ARP].hwsrc
    mac = mac.lower()
    ip = pkt[ARP].psrc

  if mac == 'xx:xx:yy:xx:yy:xx': # dash button
    toggleLight()
    sleep(5)
    return "dash button detected\n"

try:
  print( sniff(prn=arp_detect, filter="arp", store=0))
except KeyboardInterrupt:
  rfdevice.cleanup()
  exit()

This way the dash button can be used as an additional remote control in parallel to the original remote control of the power plug sockets. Although this solution cannot keep up with the original remote control regarding the response time. There are several steps in between which take their time…

Raspberry Pi Zero, dash button, remote power plug socket
Raspberry Pi Zero, dash button, remote power plug socket
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Dash Button Hacks

Quite some time ago Amazon launched the dash buttons. Amazon intends them to be used for ordering everyday products. Without even knowing the price before automatically finalizing the order! This way I don’t want to use such a button.
In the end a dash button is a relatively cheap WiFi button. Quickly the first users found out how to hack them and use them in different contexts. A dash button can be a doorbell, a phone finder, a tool for doing statistics (work started/stopped, …)  or it could simply switch the light on.
Here is a short description on how to set up a dash button for alternative uses.

Hardware

Raspberry Pi (Zero)
Amazon Dash Button

Dash Button Setup

    • Follow the setup descriptions as described here. The trick is to leave the Amazon app directly after having copied the WiFi credentials to the button.
    • Find out the dash button’s IP and MAC, e.g. by looking at the active devices in your router’s setup.
    • The button will constantly nag in the amazon app about being setup uncompletely. Block the button’s internet access using the setup of the router.

Software

A small Python script on a Raspberry Pi „sniffs“ the local network for packets of all the devices within the network. If the MAC of a dash button is found certain actions can be triggered.

Additionally required packets:

sudo pip install scapy # http://www.secdev.org/projects/scapy/
sudo apt-get install tcpdump
#!/usr/bin/python
from scapy.all import *
import httplib, urllib

def doWhatIWant():
  print "TODO"

def arp_detect(pkt):
  #pkt.show() # debug info
  if pkt[ARP].op == 1: # network request
    mac = pkt[ARP].hwsrc
    mac = mac.lower()
    ip = pkt[ARP].psrc
    print "IP: " + str(ip) + ", MAC: " + str(mac)

  if mac == 'xx:xx:xx:xx:xx:xx': # dash button
    doWhatIWant()
    sleep(5)
    return "dash button detected\n"
  else:
    print "Unknown: " + str(ip) + ", " + str(mac)
    return "Unknown MAC: " + pkt[ARP].hwsrc

try:
  print sniff(prn=arp_detect, filter="arp", store=0)
except KeyboardInterrupt:
  exit()

To run the script automatically after boot simply add a line to /etc/rc.local:

sudo python /home/pi/sniff.py&

Now the dash button is ready to be used for anything else.

To make it a doorbell or a phone finder one could use pushover. The app is installed on a smartphone. That way it is possible to send notifications to this smartphone using the pushover API  using an API and a user key.

Example code

def sendNotification(message):
  conn = httplib.HTTPSConnection("api.pushover.net:443")
  conn.request("POST", "/1/messages.json",
  urllib.urlencode({
  "token": "APItoken",
  "user": "usertoken",
  "message": str(message),
 "sound": "intermission"
 }), { "Content-type": "application/x-www-form-urlencoded" })
 conn.getresponse()

Shutdown Switch for a Raspberry Pi – or: too many Legs

A Raspberry Pi lacks a shutdown button. To keep the price down I heard.
However, simply cutting off the power of a running Pi might damage the system. This is avoidable with a simple button.

In projects that require a Pi running headless (without display) it certainly helps to have a button which triggers a safe shutdown procedure. It might not always be possible to log on to the Pi, run the custom shutdown procedure for the specific project and manually type the shutdown command.

A script triggered by a simple button can do this! The script can trigger the custom shutdown procedure for the project and can turn off the Pi afterwards.

Here’s the description of how it works for me:

Hardware

Raspberry Pi (Zero) with running OS etc
Momentary switch
Some cables

Wiring

Wiring
Wiring

The switch is connected to GND and a free pin next to the GND pin. In this case it is BCM pin 21. When the switch is pressed, an edge is detected. This signal can be used to trigger the desired actions.

Software

Short vs. Long Press

A short and a long press can be easily distuingished using a simple counter in a callback function. The callback function is triggered when an edge is detected on pin 21.

# This script will wait for a button to be pressed and then shutdown or reboot the Raspberry Pi.
# A long press initiates a reboot, a very long press initiates a shutdown.

import time
from time import sleep
import RPi.GPIO as GPIO
import os

##############CONFIG##########################
demo_mode = False
debug = False
GPIN=21
##############END CONFIG######################

GPIO.setmode(GPIO.BCM)

# Pin 21 will be input and will have its pull-up resistor (to 3V3) activated
# so we only need to connect a push button with a current limiting resistor to ground
GPIO.setup(GPIN, GPIO.IN, pull_up_down=GPIO.PUD_UP)
int_active = 0

print "Shutdown / Reboot script started."

# ISR: if our button is pressed, we will have a falling edge on pin 21
# this will trigger the interrupt:
def shutdown_reboot_callback(channel):

# button is pressed
# possibly shutdown our Raspberry Pi

global int_active

# only react when there is no other shutdown process running

if (int_active == 0):
int_active = 1
pressed = 1
shutdown = 0

# count how long the button is pressed
counter = 0

while ( pressed == 1 ):
if ( GPIO.input(GPIN) == False ):
# button is still pressed
counter = counter + 1
if debug:
print "pressed: " + str(counter)
# break if we count beyond 20 (long-press is a shutdown)
if (counter >= 20):
pressed = 0
else:
sleep(0.2)
else:
# button has been released
pressed = 0

# button has been released, count cycles and determine action

# count how long the button was pressed
if (counter < 2):
# short press, do nothing
pressed = 0
int_active = 0
if debug:
print str("short press, do nothing")

else:
if debug:
print "else " + str(counter)
# longer press
if (counter < 10):
# medium length press, initiate system reboot
if debug:
print("rebooting..")

# run the reboot command as a background process
if demo_mode:
print("sudo reboot now")
exit(0)
else:
os.system("sudo reboot now")

elif (counter>=10 and counter<20):
# long press, initiate system shutdown

if debug:
print("shutting down..")

# run the shutdown command as a background process
if demo_mode:
print("sudo shutdown now")
exit(0)
else:
os.system("sudo shutdown now")


# Program pin 21 as an interrupt input:
# it will react on a falling edge and call our interrupt routine "shutdown_reboot_callback"
GPIO.add_event_detect(GPIN, GPIO.FALLING, callback = shutdown_reboot_callback, bouncetime = 500)

while True:
if debug:
print "."
time.sleep(1)

Setup

To launch the script at startup of the Raspberry Pi place it on the pi (e.g. in /usr/bin) and  add this line to /etc/rc.local just before exit 0:

sudo python /usr/bin/shutdown_reboot.py&
Shutdown / Reboot switch on a Raspberry Pi Zero
Shutdown / Reboot switch on a Raspberry Pi Zero

And here is the solution for the attentive reader on the remark on too many legs: a common momentary switch has four legs and is squared. Actually it is a matter of orientation whether the switch works as expected…

A smart Raspberry Pi Zero DIY Text Clock

So this is the project I had in mind when I was experimenting with a NeoPixel strip on a Raspberry Pi Zero. The original text clock was invented a couple of years ago. With its elegant and timeless (yes, literally) design the QLOCKTWO is simultaneously a beautiful and useful piece of art.
It is not that I exactly needed yet another clock – but I got intrigued and wanted to create my own, smart version of a text clock.

Numerous examples of DIY versions and manuals on how to build a text clock are available on the internet. Some manuals involve soldering a lot of LEDs. I wanted to skip this step and went for a NeoPixel strip. In total I calculated 92 NeoPixels: one for each letter that can be alighted.

My version of the text clock should not only display the time in a unique way but should also indicate something more, it should be smart! This is why I chose a Raspberry Pi Zero instead of a microcontroller as a base. This way I’m able to easily get more information using a Python script along with some ready-made libraries.

My smart text clock indicates whether I have unread emails in my inbox by changing the colour of the LEDs. If desired the smart text clock is also able to indicate the weather developments depending on the outside temperature or any other criteria. The weather data is taken from openweathermap.org as in former projects.

One could also try to indicate whether a train one needs to catch regularly is on time. Or the smart text clock could be used as a traffic monitor for commuters (similar to this project idea).

Updating the smart text clock every 5 minutes should be precise enough for me. It is definitely more precise than a fuzzy clock which indicates bright and dark only.

Hardware

The hardware list of the last blog entry can be extended by the picture frame which is often used for DIY text clocks. A suitable one is sold by a well-known swedish furniture store.
Additionally some paper is useful for dispersing the light from the LEDs behind the letters.

Adhesive foil with precisely cut letters can be put on the glass to match the LEDs from the strip. Here I had professional help by friends owning a cutting plotter.

The LED strip is cut and soldered together appropriately to match the letters positions. The strip is glued with its adhesive back to the picture frame’s back plate.

The LEDs are separated by a grid behind the glass. It is printed with a 3D printer. This grid helps to avoid interferences between the different letters.

A piece of transparent paper between the glass and the grid is the possibility to make the letters look smooth. If it was missing the LEDs were directly visible. A bit of diffusion makes it look better…

Software

A straightforward python script is run automatically every five minutes. First the current time is determined. The time is translated into words with a five minute precision.

The words are mapped to the LED indices from the NeoPixel strip. These are the ones to alight to display the time.

Colour Definition

To determine which colour to use for the alighted LEDs some (optional) checks are built-in:

  • Approximately every hour the weather data is fetched from openweathermap.org using the python owm library. The temperature is extracted along with the weather code. The results are used for defining the colour of the LEDs. Other parameters can be taken into account as well.
  • The number of unread emails is checked using the Python imap library. If the number is greater than zero the LED color is changed.

During night time the brightness of the LEDs is lowered. That way the smart text clock serves as a convenient night light as well.

Source Code


#!/usr/bin/python
# -*- coding: cp1252 -*-

import time

import imaplib

import pyowm
import json
import pprint

from neopixel import *

########################CONFIG############################

OWM_APYKEY='get one from openweathermap.org'
OWM_ID = an ID number

# file to store weather state
fileName="/home/pi/textClockWeatherState.txt"

EMAIL_NAME = "user@googlemail.com"
EMAIL_PASS = "password"

# LED strip configuration:
LED_COUNT = 92 # Number of LED pixels.
LED_PIN = 18 # GPIO pin connected to the pixels (must support PWM!).
LED_FREQ_HZ = 800000 # LED signal frequency in hertz (usually 800khz)
LED_DMA = 5 # DMA channel to use for generating signal (try 5)
LED_BRIGHTNESS = 128 # Set to 0 for darkest and 255 for brightest
LED_INVERT = False # True to invert the signal (when using NPN transistor level shift)

######################END#CONFIG##########################

_start = "IT IS "
_end = " O\'CLOCK"
_numbers = ('ONE', 'TWO', 'THREE', 'FOUR', 'FIVE', 'SIX', 'SEVEN', 'EIGHT', 'NINE', 'TEN', 'ELEVEN', 'TWELVE')
_past = ' PAST '
_to = ' TO '
_fivepast = 'FIVE PAST '
_tenpast = 'TEN PAST '
_aquarter = 'A QUARTER '
_twenty = ' TWENTY'
_twentyfive = ' TWENTYFIVE'
_half = ' HALF'
_fiveto = 'FIVE TO '
_tento = 'TEN TO '

'''
I T L I S A S T I M E 0,1, 2,3
A C Q U A R T E R D C 4, 5,6,7,8,9,10,11
T W E N T Y F I V E X 12,13,14,15,16,17, 18,19,20,21
H A L F B T E N F T O 22,23,24,25, 26,27,28, 29,30
P A S T E R U N I N E 31,32,33,34, 35,36,37,38
O N E S I X T H R E E 39,40,41, 42,43,44, 45,46,47,48,49
F O U R F I V E T W O 50,51,52,53, 54,55,56,57, 58,59,60
E I G H T E L E V E N 61,62,63,64,65, 66,67,68,69,70,71
S E V E N T W E L V E 72,73,74,75,76, 77,78,79,80,81,82
T E N S E O C L O C K 83,84,85
'''
# map time to precise LED indices
_timeLightMap = {
'IT IS ' : (0,1,2,3),
' HALF' : (22,23,24,25),
' PAST ' : (31,32,33,34),
' TO ' : (29,30),
'FIVE PAST ' : (18,19,20,21, 31,32,33,34),
'TEN PAST ' : (26,27,28, 31,32,33,34),
'A QUARTER ' : (4, 5,6,7,8,9,10,11),
' TWENTY' : (12,13,14,15,16,17),
' TWENTYFIVE' : (12,13,14,15,16,17, 18,19,20,21),
' HALF PAST ' : (22,23,24,25, 31,32,33,34),
' TWENTYFIVE TO ' : (12,13,14,15,16,17, 18,19,20,21, 29,30),
' TWENTY TO ' : (12,13,14,15,16,17, 29,30),
'TEN TO ' : (26,27,28, 29,30),
'FIVE TO ' : (18,19,20,21, 29,30),
'ONE' : (39,40,41),
'TWO' : (58,59,60),
'THREE' : (45,46,47,48,49),
'FOUR' : (50,51,52,53),
'FIVE' : (54,55,56,57),
'SIX' : (42,43,44),
'SEVEN' : (72,73,74,75,76),
'EIGHT' : (61,62,63,64,65),
'NINE' : (35,36,37,38),
'TEN' : (83,84,85),
'ELEVEN' : (66,67,68,69,70,71),
'TWELVE' : (77,78,79,80,81,82),
' O\'CLOCK' : (0,1,2,3)
}

class SmartTextClock():

def run(self):
print "A SMART TEXT CLOCK"

def check_googlemail(self, login, password):
# if new mail return # emails
obj = imaplib.IMAP4_SSL('imap.gmail.com','993')
obj.login(login, password)
obj.select()
nofUnreadMessages = len(obj.search(None, 'UnSeen')[1][0].split())
print "Unread emails: " + str(nofUnreadMessages)
return nofUnreadMessages

def clock(self):
t = time.strftime("%H:%M")
print t
return t

def translateHour(self, hour, offset):
if hour == '00' or hour == '12':
if offset == True:
return _numbers[0]
else:
return _numbers[11]
if hour == '1' or hour == '13':
if offset == True:
return _numbers[1]
else:
return _numbers[0]
if hour == '2' or hour == '14':
if offset == True:
return _numbers[2]
else:
return _numbers[1]
if hour == '3' or hour == '15':
if offset == True:
return _numbers[3]
else:
return _numbers[2]
if hour == '4' or hour == '16':
if offset == True:
return _numbers[4]
else:
return _numbers[3]
if hour == '5' or hour == '17':
if offset == True:
return _numbers[5]
else:
return _numbers[4]
if hour == '6' or hour == '18':
if offset == True:
return _numbers[6]
else:
return _numbers[5]
if hour == '7' or hour == '19':
if offset == True:
return _numbers[7]
else:
return _numbers[6]
if hour == '8' or hour == '20':
if offset == True:
return _numbers[8]
else:
return _numbers[7]
if hour == '9' or hour == '21':
if offset == True:
return _numbers[9]
else:
return _numbers[8]
if hour == '10' or hour == '22':
if offset == True:
return _numbers[10]
else:
return _numbers[9]
if hour == '11' or hour == '23':
if offset == True:
return _numbers[11]
else:
return _numbers[10]
return ''

# time format: HH:mm
def translateTime(self, time):
t = time.split(':', 1)
print t
h = str(t[0])
m = str(t[1])
print h + ":" + m

indices = (1,2)

if float(m) >= 0.0 and float(m) <= 2.5:
#IT IS X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[self.translateHour(h, False)] + _timeLightMap[_end]
if float(m) > 2.5 and float(m) <= 7.5:
#IT IS FIVE PAST X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_fivepast] + _timeLightMap[self.translateHour(h, False)] + _timeLightMap[_end]
if float(m) > 7.5 and float(m) <= 12.5:
#IT IS TEN PAST X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_tenpast] + _timeLightMap[self.translateHour(h, False)] + _timeLightMap[_end]
if float(m) > 12.5 and float(m) <= 17.5:
#IT IS A QUARTER PAST X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_aquarter] + _timeLightMap[_past] + _timeLightMap[self.translateHour(h, False)] + _timeLightMap[_end]
if float(m) > 17.5 and float(m) <= 22.5:
#IT IS TWENTY PAST X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_twenty] + _timeLightMap[_past] + _timeLightMap[self.translateHour(h, False)] + _timeLightMap[_end]
if float(m) > 22.5 and float(m) <= 27.5:
#IT IS TWENTYFIVE PAST X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_twentyfive] + _timeLightMap[_past] + _timeLightMap[self.translateHour(h, False)] + _timeLightMap[_end]
if float(m) > 27.5 and float(m) <= 32.5:
#IT IS HALF PAST X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_half] + _timeLightMap[_past] + _timeLightMap[self.translateHour(h, False)] + _timeLightMap[_end]
if float(m) > 32.5 and float(m) <= 37.5:
#IT IS TWENTYFIVE TO X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_twentyfive] + _timeLightMap[_to] + _timeLightMap[self.translateHour(h, True)] + _timeLightMap[_end]
if float(m) > 37.5 and float(m) <= 42.5:
#IT IS TWENTY TO X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_twenty] + _timeLightMap[_to] + _timeLightMap[self.translateHour(h, True)] +_timeLightMap[_end]
if float(m) > 42.5 and float(m) <= 47.5:
#IT IS A QUARTER TO X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_aquarter] + _timeLightMap[_to] + _timeLightMap[self.translateHour(h, True)] + _timeLightMap[_end]
if float(m) > 47.5 and float(m) <= 52.5:
#IT IS TEN TO X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_tento] + _timeLightMap[self.translateHour(h, True)] + _timeLightMap[_end]
if float(m) > 52.5 and float(m) <= 57.5:
#IT IS FIVE TO X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[_fiveto] + _timeLightMap[self.translateHour(h, True)] + _timeLightMap[_end]
if float(m) > 57.5 and float(m) <= 59.9:
#IT IS TO X O'CLOCK
indices = _timeLightMap[_start] + _timeLightMap[self.translateHour(h, True)] + _timeLightMap[_end]
return indices

def selectColor(self, weatherCondition):
# Email: Lime Green 50-205-50
# http://www.tayloredmktg.com/rgb/
color = Color(255, 222, 173)
# weatherCondition = 'fair' # 'good', 'fair, 'bad'
if weatherCondition == 'fair':
color = Color(255, 222, 173) # Navajo White 255-222-173 # Lemon Chiffon 255-250-205
if weatherCondition == 'good':
color = Color(255, 127, 80) # Coral 255-127-80 # Light Salmon 255-160-122
if weatherCondition == 'bad':
color = Color(70, 130, 180) # Steel Blue 70-130-180
return color

def getWeatherFromOWM(self):
owm = pyowm.OWM(OWM_APYKEY, version='2.5')
# Search for current weather
print "Weather @ID"
obs = owm.weather_at_id(OWM_ID)
w1 = obs.get_weather()
print(w1)
print w1.get_status()

weatherCondition = 'fair' # 'good', 'fair, 'bad'

# get general meaning for weather codes https://openweathermap.org/weather-conditions
weatherCode = w1.get_weather_code()
print weatherCode
print w1.get_sunset_time('iso')
temperature = w1.get_temperature('celsius')['temp']
print str(temperature) + " C"

# simple: judge weather on temperature
if temperature<=10.0:
weatherCondition = 'bad'
if temperature>10.0 and temperature<20.0:
weatherCondition = 'fair'
if temperature>=20.0 and temperature<35.0:
weatherCondition = 'good'
if temperature>=35.0:
weatherCondition = 'bad'

return weatherCondition

def readSavedWeatherCondition(self):
weatherCondition = 'fair' # default
try:
print 'Read file ' + fileName
target = open(fileName, 'r')
weatherCondition = target.read()
print weatherCondition
target.close()
except IOError:
print fileName + " does not exist yet. Creating a default file."
self.saveWeatherConditionToFile(weatherCondition)
pass
return weatherCondition

def saveWeatherConditionToFile(self, weatherCondition):
try:
print 'Write file ' + fileName
target = open(fileName, 'w')
target.write(weatherCondition)
target.close()
except:
print 'File ' + fileName + ' could not be written.'

# NEOPIXEL: GRB
#strip.setPixelColor(i, Color(0,0,120)) # B
#strip.setPixelColor(i, Color(0,120,0)) # R
#strip.setPixelColor(i, Color(120,0,0)) # G
def alight(self, LEDindices, color):
print 'Alight indices ' + str(LEDindices)
for i in LEDindices:
strip.setPixelColor(i, color)
strip.show()

if __name__ == "__main__":
app = SmartTextClock()
app.run()

# check for unread emails
unreadEmails = app.check_googlemail(EMAIL_NAME, EMAIL_PASS)

# get time and determine LED indices
time = app.clock()
indices = app.translateTime(time)
print "Indices " + str(indices)

# investigate weather data
weatherCondition = app.readSavedWeatherCondition()

# update weather data every hour
theTime = time.split(":")
# this range should be met from time to time
if int(theTime[1])>=0 and int(theTime[1])<=7:
weatherCondition = app.getWeatherFromOWM()
app.saveWeatherConditionToFile(weatherCondition)

# create NeoPixel object with appropriate configuration
strip = Adafruit_NeoPixel(LED_COUNT, LED_PIN, LED_FREQ_HZ, LED_DMA, LED_INVERT, LED_BRIGHTNESS)
# intialize the library (must be called once before other functions)
strip.begin()

# low light during 19-8 o'clock
if(8 < int(theTime[0]) > 19):
strip.setBrightness(200)
else:
strip.setBrightness(50)

stripColor = Color(120,120,120)

# select color depending on weather condition
if weatherCondition == 'bad':
stripColor = Color(0, 120, 0)
if weatherCondition == 'fair':
stripColor = Color(120, 120, 120)
if weatherCondition == 'good':
stripColor = Color(0,0,120)

if unreadEmails > 0:
stripColor = Color(205,50,50)

app.alight(indices, stripColor)

 

Audio Book: Raspberry Pi Zero Internet Radio with pHAT BEAT

A couple of days ago I laid my hands on a pHAT BEAT and two small speakers. Together with a Raspberry Pi Zero (and an Internet connection of course) this makes building an internet radio easily possible. And yes, inspiration for this project was also the Pirate Radio Kit.
The pHAT BEAT comes along with stereo output, an amplifier, a couple of buttons for adjusting the volume, playing/pause, forward/backward and powering off and a number of bright and shiny LEDs. Just the perfect audio hardware component for an internet radio.

Hardware

Raspberry Pi Zero with Micro SD card and up-to-date OS
USB WiFi stick (not needed if a Raspberry Pi Zero W is used)
pHAT BEAT
2
small speakers
some cables
USB power supply

Assemble the hardware as required. This implies some soldering for the headers of the Raspberry Pi Zero and the pHAT BEAT as well as the connections to the speakers. This tutorial is a good guideline to see what to do.

Software

Once the Raspberry Pi Zero is accessible headless in the local WLAN network (see this blog post for setup instructions) install the pHAT BEAT Python library.

Luckily the software for an internet radio project already exists. The setup is really made simple by running the setup script only. The setup script installs the required software and adjusts the whole configuration on the Raspberry Pi Zero. See https://github.com/pimoroni/phat-beat/tree/master/projects/vlc-radio for further reference.

Once the installation is complete, reboot. After reboot the internet radio will be automatically started and will play some example music.

The pHAT BEAT’s buttons directly work with the example projects software. Adjusting the volume or switching between different items on a configurable playlist (see configuration below) is directly possible. Even the off button immediately works: it turns off the radio and fully shuts down the Raspberry Pi Zero.

Configuration

Configure Internet Radio Streams

Collect the URLs of your favourite internet radio streams. Create the file /home/pi/.config/vlc/playlist.m3u . Insert the URLs into the playlist as in this example:

Example playlist.m3u
#EXTM3U
#EXTINF:0,station1
#EXTVLCOPT:network-caching=1000
http://station1.net/.../...
#EXTINF:0,station2
http://station2.com/.../.../mp3/...
#EXTINF:0,station3
http://station3.something/...

Alternatively create a playlist containing the radio stream URLs of your choice in VLC and save the playlist to a file. This file can be copied to the Raspberry Pi Zero to /home/pi/.config/vlc/playlist.m3u.

After reboot the forward/backward buttons of the pHAT BEAT can be used to switch between the different internet radio streams.

Wrapping: The Result

The wrapping was simple in this case: an old book became a nice „audio book“! Similar to my ‚book book shelves‘ an old book is hollowed inside with a sharp knife so the hardware fits in.
Surprisingly well is the sound of the speakers inside the book!
All I need now is to find a way to operate the small buttons of the pHAT BEAT…

Info & Links

https://github.com/pimoroni/phat-beat

 

NeoPixels Strip on Raspberry Pi Zero

Looking into my desk’s drawer I found the remainder of an Adafruit NeoPixel strip I used in another project. And an unused, last years Raspberry Pi Zero. Does that work together? Well, yes, it does! At least after fiddling a bit with hard- and software and circumventing some common traps.

Searching the web I found a tutorial for steering a NeoPixel strip with a first generation Raspberry Pi. Technically it should work with an exemplary of a more recent version, but it did not initially.
Here is the description of how it all worked out in the end:

Hardware

Raspberry Pi Zero with up-to-date Raspbian Jessie Pixel
Mini USB WiFi Adapter (if the brand new Raspberry Pi Zero W is not used)
Raspberry Pi Zero adapter cables + power supply
Adafruit NeoPixel strip
1000 μF capacitor
330 Ω resistor
1N4001 diode
5 V breadboard power supply
breadbord, cables

Connections

  • 5V power supply GND : 1000 μF capacitor (short leg)
  • 5V power supply 5V : 1000 μF capacitor
  • 5V power supply GND : NeoPixel strip GND
  • 5V power supply 5V : NeoPixel strip 5V via 1N4001 diode (side with stripe goes to 5V input of the strip)
  • 5V power supply GND : Raspberry Pi Zero GND (physical pin 6)
  • Raspberry Pi Zero (physical pin 12) : NeoPixel strip data line via 330 Ω resistor

The available pins of the Raspberry Pi Zero are listed here. GPIO #1 correlates to physical pin 12 which is BCM #18. The latter is used in the Python software.

Don’t!

It is not recommended to use the 5V output of the Raspberry Pi Zero directly to power the NeoPixel strip. The pixels might draw too much current and might therefore damage the pin. It would have been way too convenient…so: an additional 5V power supply is strongly recommended.

Software

Running Headless: Setting up WiFi

To run the Raspberry Pi Zero headless (without display), set up the WiFi connection. For this step an HDMI display and a keyboard is required. Open the file

sudo nano /etc/wpa_supplicant/wpa_supplicant.conf

Put the network configuration at the end of the file:

network={
ssid="WiFi network name"
psk="password"
}

Use raspi-config to allow SSH connections and to adjust the Pi’s hostname, the password, the time settings etc. .

SSH to Zero

When attaching the Mini USB WiFi Adapter instead of the keyboard and rebooting the Raspberry Pi Zero the desired WiFi network is used and it is possible to SSH to the Pi Zero. To find the IP adress in the local network check which devices are logged into the network at your routers access point. Or kindly ask your network admin to check. 😉

GPIO Checks

To see the available GPIO pins on the Raspberry Pi Zero run

gpio readall

NeoPixel Python Library

To set up the Python library for driving NeoPixels on a Raspberry follow this tutorial. Jeremy Garff’s Python library for NeoPixels is working like a charm.

Disabling Audio

To be able to use the PWM pins as data pins for the NeoPixel strip I disabled audio by commenting the line

# Enable audio (loads snd_bcm2835)
#dtparam=audio=on  # disable audio for PWM pin usage

in the file /boot/config.txt.

Whether audio is disabled can be checked using

aplay -l

. If audio is disabled properly the result is an error message („aplay: device_list:268: no soundcards found…“).

Examples

Once the NeoPixel library is set up and the hardware is connected properly run strandtest.py or any other example code from the rpi_ws281x/python/examples section.

Result

That’s it! The NeoPixel strip finally can be driven by a Raspberry Pi Zero.

neopixeltest

While this example is working I definitively have a new project in mind…

Links

https://learn.adafruit.com/neopixels-on-raspberry-pi/overview

https://github.com/jgarff/rpi_ws281x