Rasperry pi

与Arduino稍有不同的是，这是源于英国中学的开源项目，用900M ARM CPU，可以解码高清视频。缺点是3.3V，I/O电流小（可用TXB0108 转为5V，但I2C不行），开发也较复杂。它可直接装Linux（wheezy raspbian或Ubuntu core）/Android/Windows 10 loT core做开发应用，微软也卖硬件。如果选择的话，能用Arduino完成的就别用RasberryPi。比如实时性的，Rasberry PWM的周期就很慢。

变种硬件，如国产Banana Pi，硬件挺好，软件/支持/和寿命难说。http://www.leiphone.com/news/201406/raspberry-pi-geek-other.html  http://www.udoo.org/ 

Rasperry Pi用Python编程, IDE: https://blog.idrsolutions.com/2014/12/top-8-ides-programmers-coders-beginners-raspberry-pi/ 

支持ZFS: https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=19062 

SATA multiplier JMB321： http://www.htpcguides.com/rebuild-bananian-kernel-with-sata-port-multiplier-support/ 

多OS支持：https://books.google.com/books?id=zXz5CwAAQBAJ&pg=SL1-PA1&lpg=SL1-PA1&dq=Raspberry+Pi+2+开发 

入门：https://sites.google.com/site/raspberrypidiy/extend 

http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/temperature/ 

Rasperry Pi 3：

https://www.raspberrypi.org/blog/raspberry-pi-3-on-sale/ 

3.3-5V i2C converter:

GPIO: http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/temperature/#exampleCode 

## button.py
# import necessary library
import RPi.GPIO as GPIO   
import time   
# to use Raspberry Pi board pin numbers
GPIO.setmode(GPIO.BOARD)   
# set up pin 11 as an output
GPIO.setup(11, GPIO.IN)
# enter while loop unitl exit
while True:
# set up input value as GPIO.11
   inputValue = GPIO.input(11)
# when user press the btn
   if inputValue== False:
# show string on screen   
      print("Button pressed ")
      while inputValue ==  False:  
# Set time interval as 0.3 second delay
            time.sleep(0.3)   

##Blink.py
# import necessary library
import RPi.GPIO as GPIO   
import time   
# to use Raspberry Pi board pin numbers
GPIO.setmode(GPIO.BOARD)   
# set up pin 11 as an output
GPIO.setup(11, GPIO.OUT)
# enter while loop unitl exit
while True:
# Make an LED flash on
   GPIO.output(11,True)  
# Set time interval as 1 second delay
   time.sleep(1)    
# Make an LED flash off  
   GPIO.output(11,False)
# Set time interval as 1 second delay
   time.sleep(1) 

wifi打印服务器：http://bbs.wenxuecity.com/computer/235417.html 

https://www.adafruit.com/product/4884 硬件也包括arduino等，Pi RP2040类似nano仅12刀，芯片仅1刀，32bit Cortex M+双核125M@3V3，支持C/C++，Python。板带264K RAM，8M Flash，21xGPIO，4x12bit ADC,2 I2C/SPI/UART, 16x PWM, 内置0.2A锂电充，RGB NeoPixel