Add instructions for setting up on Raspbian in voicekit branch. (#149)

HACKING.md

@@ -0,0 +1,74 @@
+# Setting up the image
+
+We recommend using [the images](https://aiyprojects.withgoogle.com/voice) we
+provide. Those images are based on [Raspbian](https://www.raspberrypi.org/downloads/raspbian/),
+with a few customizations and are tested on the Raspberry Pi 3. If you prefer
+to setup Raspbian yourself, there are some manual steps you need to take.
+
+## Installing the dependencies
+
+First, make sure you have `git` installed and clone this repository in
+`~/voice-recognizer-raspi`:
+
+```shell
+sudo apt-get install git
+cd
+git clone https://github.com/google/aiyprojects-raspbian.git voice-recognizer-raspi
+```
+
+Then, install the project dependencies and setup the services:
+
+``` shell
+cd ~/voice-recognizer-raspi
+scripts/install-deps.sh
+sudo scripts/install-services.sh
+```
+
+## Configuring the Voice HAT driver
+
+To use the Voice HAT, your kernel needs to be 4.9 or later. This is available
+on Raspbian 2017-07-05 and later. You'll also need to configure ALSA:
+
+``` shell
+sudo scripts/configure-driver.sh
+sudo scripts/install-alsa-config.sh
+sudo reboot
+```
+
+## Get cloud credentials
+
+To access the cloud services you need to register a project and generate
+credentials for cloud APIs. This is documented in the
+[setup instructions](https://aiyprojects.withgoogle.com/voice#users-guide-1-1--connect-to-google-cloud-platform) on the
+webpage.
+
+## Making code changes
+
+If you edit the code on a different computer, you can deploy it to your
+Raspberry Pi by running:
+
+``` shell
+make deploy
+```
+
+## Running automatically
+
+You can find sample scripts in the `src` directory showing how to use the
+Assistant SDK.
+
+To execute any of these scripts on the Raspberry Pi, login to it and run
+(replacing the filename with the script you want to run):
+
+``` shell
+cd ~/voice-recognizer-raspi
+source env/bin/activate
+python3 src/assistant_library_demo.py
+```
+
+If you want the voice recognizer service to run automatically when the Pi
+boots, you need to have a file in the `src` directory named `main.py`. You can
+make a copy of one of the sample scripts and rename it. Then run this command:
+
+``` shell
+sudo systemctl enable voice-recognizer.service
+```

systemd/voice-recognizer.service

@@ -0,0 +1,16 @@
+[Unit]
+Description=voice recognizer
+After=network.target ntpdate.service
+
+[Service]
+Environment=VIRTUAL_ENV=/home/pi/voice-recognizer-raspi/env
+Environment=PATH=/home/pi/voice-recognizer-raspi/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
+ExecStart=/home/pi/voice-recognizer-raspi/env/bin/python3 -u src/main.py
+WorkingDirectory=/home/pi/voice-recognizer-raspi
+StandardOutput=inherit
+StandardError=inherit
+Restart=always
+User=pi
+
+[Install]
+WantedBy=multi-user.target