Introduction of Raspberry Pi

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# Introduction of Raspberry Pi
.right[Hong]
---

# What Is Raspberry Pi
> "The [Raspberry Pi](https://www.raspberrypi.org/help/what-is-a-raspberry-pi/) is a low cost, credit-card sized computer 
> that plugs into a computer monitor or TV, and uses a standard keyboard and mouse."

> "Our Foundation’s goal is to advance the education of adults and children, 
> particularly in the field of computers, computer science and related subjects. "

The Raspberry Pi Foundation is a registered educational charity based in the UK.

???
lightweight, cheap, power save, small, as a controller
---

# Models
#### Two models.     
The small model, [Raspberry Pi 2 Model B](https://www.raspberrypi.org/products/raspberry-pi-2-model-b/).      
And the even smaller model, [Raspberry Pi Zero](https://www.raspberrypi.org/products/pi-zero/).

<div style="text-align: center;">
  <a href="https://www.raspberrypi.org/products/pi-zero/">
    <img src="raspberry-pi-intro/model-0.png" style="width:50%;">
  </a>
</div>
---
    
# Specs of Raspberry Pi 2 Model B   
It's published in February 2015 to replace old Raspberry Pi 1 Model B+.
Price is **$35**.

- A 900MHz quad-core **ARM** Cortex-A7 CPU
- 1GB RAM
- 4 USB ports
- 40 GPIO(general purpose input/output) pins 
- Full HDMI port
- Ethernet port
- Combined 3.5mm audio jack and composite video
- Camera interface (CSI)
- Display interface (DSI)
- Micro SD card slot
- VideoCore IV 3D graphics core

Because it has an ARMv7 processor, it can run the full range of ARM GNU/Linux distributions, as well as [Microsoft Windows 10](https://www.raspberrypi.org/blog/raspberry-pi-2-on-sale/).
???
可以连接风扇、继电器等等
---
     
# Specs of Raspberry Pi Zero
Half the size of a Raspberry Pi 2 Model B. 
Only **$5**.

- 1Ghz, Single-core CPU
- 512MB RAM
- Mini HDMI and USB On-The-Go ports
- Micro USB power
- HAT-compatible 40-pin header
- Composite video and reset headers    
---

# Buy a Raspberry Pi and Accessories

- Raspberry Pi 2 Model B, ¥238.00, *[Purchase Link](https://detail.tmall.com/item.htm?id=43782363457&spm=a1z09.2.0.0.lqDBev&_u=n1l0dhodd4a)*
- Shell, ¥13.90
- Fan, ¥13.90 
- EDUP EP-N8508GS USB Wireless network card, ¥29.00, *[Purchase Link](http://item.jd.com/509932.html)*
- 5V 2A USB Power Adapter Huawei, ¥35, *[Purchase Link](http://item.jd.com/1333526.html)*
- micro-SD card SanDisk, ¥33, *[Purchase Link](http://item.jd.com/1875996.html)*
- HDMI cable *(One Time Usage)* 
- Keyboard *(One Time Usage)*
- Mouse *(One Time Usage)*

**¥362.8** in total. 
<div style="text-align: center;">
	<img src="raspberry-pi-intro/my-pi.jpg" style="width:42%;">
</div>  
???
买的时候，没有在国内找到官方的销售渠道，淘宝买的
风扇有噪音，天冷不用开
自带了一个读卡器，如果没有，买一个读卡器
一般只在安装系统使用一次
---

# Set Up - Install an Operating System
[NOOBS](https://www.raspberrypi.org/help/noobs-setup/) (New Out Of the Box Software), an easy operating system install manager for the Raspberry Pi.

- Download NOOBS
- Format the SD Card via SD Formatter 4.0 
- Extract NOOBS and drop all files onto the SD card.
- Connect keyboard, mouse and monitor, and boot.

---

# Set Up - Connect to Wifi
EDUP EP-N8508GS is **driver free** on Raspberry Pi.

Plug in the EDUP EP-N8508GS and check if it works.
```bash
$ lsusb
# If EP-N8508GS works, it should be listed in the output.
$ iwconfig
# If EP-N8508GS works, you will see `wlan0` in the output
```
List SSID of Wifi.
```bash
$ iwlist wlan0 scan
```
Copy generated psk information to `wpa_supplicant.conf` file.
```bash
$ wpa_passphrase ssid wifi-password
```
Edit `/etc/network/interfaces` file and start connecting to Wifi.
```bash
$ sudo ifup wlan0
```
---

# Remote Login
Configure your Router to assign a **static IP** address for your Pi.

For desktop/laptop, you can login your Pi via `ssh`.

For mobile phone, try Serverauditor, which is available on both iOS and Android.

<div style="text-align: center;">
	<img src="raspberry-pi-intro/serverauditor-screen.jpeg" style="width:30%;">
</div>
---

# Application, a Music Alarm
Play music to wake myself up in the morning.

### How it works

- Copy (favorite) songs to Pi.    
- A tiny Python script to play songs.      
- A cron job as the timer.

### Future improvement

- "Copy and play" is too old fashion. Use a cloud music service. (A [open sourced](https://github.com/darknessomi/musicbox) CLI player for 网易云音乐.)
???
网易云音乐有web api；随时在手机上修改播放列表
---

# Application, a Music Alarm, Source
```python
import os, glob, random

def playSongs():
    location = '/home/pi/Music'
    os.chdir(location)

max = 2
    songs = glob.glob('*.mp3')
    # shuffle
    size = len(songs)
    for x in range(0, size):
        pick = random.randint(x, size-1)
        (songs[x], songs[pick]) = (songs[pick], songs[x])

for x in songs[:max]:
        play_mpg321(x)

def play_mpg321(song):
    cmd = 'mpg321 "' + song + '"'
    os.system(cmd)

if __name__    == "__main__":
   playSongs()
```

25 7 * * 1,2,3,4,5  python /home/pi/workspace/raspberry-pi/music.py
---

# Application, a Weather Forecaster
Sometimes, you just too lazy to open up an app to check weather before leaving home.

Speak out PM 2.5 index, temperature, weather condition loudly in the morning.

### How it works.
- Parse [中国天气网](http://www.weather.com.cn/weather1d/101020100.shtml) HTML page to get data. (A free weather API is not easy to get.)
- A [TTS(text to speech) API](http://tts.baidu.com/text2audio?lan=zh&pid=101&ie=UTF-8&text=%25E5%25A4%25A7%25E5%25AE%25B6%25E5%25A5%25BD) to generate voice (From Baidu).
- A cron job as the timer.

```bash
23,35 7 * * 1,2,3,4,5  cd /home/pi/log/ && python /home/pi/workspace/raspberry-pi/weather.py --hours 8,9,17,18 --history 5 >> /home/pi/log/weather.log 2>&1
```

[Source code](https://github.com/RockHong/raspberry-pi/blob/master/weather.py)

[Voice Sample](raspberry-pi-intro/2016-01-29.mp3)
---

# Application, a VOD Service
A video on demand service, which is able to stream videos to iPhone, iPad and desktop.

#### How it works

- A responsive UI by Bootstrap
- [HTTP Live Streaming/HLS](https://developer.apple.com/library/ios/documentation/NetworkingInternet/Conceptual/StreamingMediaGuide/Introduction/Introduction.html#//apple_ref/doc/uid/TP40008332-CH1-SW1) standard from Apple
- Serve video by NGINX

#### To be improved

- Performance issue.
- Disk space waste. [NGINX Plus](https://www.nginx.com/products/streaming-media-delivery/) provides a better solution, but it's not free.

<div style="text-align: center;">
	<img src="raspberry-pi-intro/vod.jpg" style="width:32%;">
</div>
---

# Applications from Other Users

- [远程开门器](http://blog.douban.com/douban/2013/01/07/2135/) 
- [家庭监控和移动目标探测](http://python.jobbole.com/81645/) 
- Airplay Server
- And many many others...

???
tv box
wireless switch; smart home?
http://ukonline2000.com/
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# Thanks