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Internet of Things

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Internet of Things

Setting up Raspberry Pi

  • [MQTT Official Site]http://www.mqttfx.org

  • Install VNC Server
    Running VNCServer at Startup

  • Command+K
    vnc://172.25.0.121:5901

  • Free MQTT Dasboard
    http://www.mqtt-dashboard.com

  • MQTT Client: MQTTFx
    broker.hivemq.com
    brew install mqttfx

  • Install mosquitto client on rPi
    sudo apt-get mosquitto-client
    sudo apt-get mosquitto # optional

  • In the first terminal run
    $ mosquitto_sub -h 127.0.0.1 -t myTopic

  • In the second terminal run
    $ mosquitto_pub -h 172.0.0.1 -t myTopic -m “Hello, world”

Connect to GrovePi

Refer to: Quick Start Guide to the GrovePi.

  1. Connect the GrovePi to Raspberry Pi

image

  1. Install the GrovePi repository

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    curl -kL dexterindustries.com/update_grovepi | sudo bash

  2. Check if Raspberrypi has connected to Grovepi

    1
    sudo i2cdetect -y 1

Example

  1. “Hello, World!” Example: LED Blink

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    cd /home/pi/Dexter/GrovePi/Software/Python
    sudo python grove_led_blink.py

  2. LED Fade

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    # fade_led.py
    # python fade_led.py

    import time
    import grovepi

    # Connect the Rotary Angle Sensor to analog port A2
    potentiometer =  2

    # Connect the Grove LED to digital port D5
    # SIG,NC,VCC,GND
    led = 5

    # Digital ports that support Pulse Width Modulation (PWM)
    # D3, D5, D6

    # Digital ports that do not support PWM
    # D2, D4, D7, D8

    grovepi.pinMode(led,"OUTPUT")
    time.sleep(1)
    i = 0

    while True:
        try:
            # Reset
            # if i > 255:
            #    i = 0

            # Current brightness
            i = grovepi.analogRead(potentiometer) / 4
            print (i)

            # Give PWM output to LED
            grovepi.analogWrite(led,i)

            # Increment brightness for next iteration
            # i = i + 20
            time.sleep(.5)

        except KeyboardInterrupt:
            grovepi.analogWrite(led,0)
            break
        except IOError:
            print ("Error")

  3. LED

CheatSheet

  • Logon
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    ssh pi@ip_addr  
    # passwd:pi
  • Reset root passwd
    1
    sudo passwd root