This is a little alarm clock application that I made so my 3yo son would know when it was time to come downstairs in the morning.
At 5am it turns on a red LED (indicating that it is time to stay in bed), then at 7am it turns on a green LED indicating that he can come downstairs to play.
From vanilla Raspbian (2015-05-15) use a wired ethernet (or USB ethernet) connection and boot the pi.
SSH into the pi with the default credentials:
username: pi
password: raspberry
Now run sudo raspi-config and make the following changes.
- Expand the file system to use the whole MicroSD Card
- Change the default user password (optional)
- Change the default locale to en-US UTF-8 UTF-8
- Change the timezone to America/Denver
- Change the keyboard layout to a US layout
- Change the hostname to pi1
This setup is based on these WiFi Settings.
nano /etc/network/interfaces
auto lo
iface lo inet loopback
auto eth0
allow-hotplug eth0
iface eth0 inet manual
allow-hotplug wlan0
auto wlan0
iface wlan0 inet dhcp
wpa-ssid YOURESSID
wpa-psk YOURWPAPASSWORD
echo 'options 8192cu rtw_power_mgnt=0 rtw_enusbss=0' > /etc/modprobe.d/8192cu.conf
I connected the red LED to pin 11 (gpio17) and the green LED to pin 15 (gpio22).
echo "deb http://packages.erlang-solutions.com/debian wheezy contrib" >> /etc/apt/sources.list
wget http://packages.erlang-solutions.com/debian/erlang_solutions.asc
sudo apt-key add erlang_solutions.asc && rm erlang_solutions.asc
sudo apt-get update
apt-get install -y --force-yes erlang-mini upstart htop
# You will have to confirm the switch to upstart by typing 'Yes, do as I say!'
mkdir /opt/elixir-1.0.4
curl -L https://github.com/elixir-lang/elixir/releases/download/v1.0.4/Precompiled.zip -o /opt/elixir-1.0.4/precompiled.zip
cd /opt/elixir-1.0.4
unzip precompiled.zip
echo 'export PATH=/opt/elixir-1.0.4/bin:$PATH' >> /etc/bash.bashrc
# do this as root so we have access to the gpio pins
git clone [email protected]:mmmries/pi-alarm-clock.git /opt/pi-alarm-clock
cd /opt/pi-alarm-clock
mix local.hex
mix deps.get
MIX_ENV=prod mix compile
cp upstart /etc/init/blinky.log
start blinky
To stop the project open a remote shell and execute:
Application.stop(:blinky)
init:stop()Or from a local iex session (with the same cookie) run:
:rpc.call(:pi@pi1, Application, :stop, [:blinky])
:rpc.call(:pi1@pi1, :init, :stop, [])If you want to checkout what is going on inside the erlang node running on your pi you can connect to it remotely using a command like
iex --sname laptop --cookie pi --remsh blinky@pi1
Note: Make sure you use the same cookie as you used when booting the application on the pi and make sure your computer knows how to resolve the address of the pi
The easiest way to check if the alarm clock is still running is to look at the status LED (green LED on the pi). If the application is running it will be blinking the green LED on/off every 1 second as a heartbeat.
You can also run the listen.rb ruby script inlcuded in this project which will listen for the log messages being published via UDP broadcast.
$ ruby listen.rb