Contents


Overview

Skill Level: Intermediate

This recipe explains the details required to setup a DJI Matrice 100 so that it can deliver a package using the IBM Watson IoT Platform.

Ingredients

DJI Matrice 100

Raspberry Pi
iPhone

Servo Motor

Slide2

Step-by-step

  1. Connect the Raspberry Pi to IBM Watson IoT Platform

    Create a Watson IoT device
    This section describes how to create an IoT device into Watson IoT and generates associated API keys for future access.

    If you do not have yet an Organization created for “Internet Of Things”, you first have to connect to Bluemix and reach the “Internet of Things” services section in the Catalog : https://bluemix.net Select “Internet of Things Platform” and then select the Free pricing plan if it is appropriate for your usage, populate the name and credential fields; press Create.

     

     

    If you have just created your “IoT” service with the previous step, you should be automatically connected to IBM Watson IoT Platform when selecting “Launch the dashboard”. If you already had one, please connect now to Watson IoT https://internetofthings.ibmcloud.com.

     

    Select your Organisation

    Open the “Devices” section

    Press “+Add Device” button

    Create a “Device Type” (if needed)Create device typeName : Raspberry Pi Device
    Description : A Raspberry Pi Device
    Press Next and optionally select attributes (Serial number, Manufacturer, … ). If not needed, leave empty.
    Press Next
    Press Next to submit information
    Declare optional metadata. If not needed, leave empty.
    Press Create

     

     

     

    The “Raspberry PiDevice” type should be available into the selectable list

    Select “Raspberry PiDevice” type and DO NOT press “Create device type” but press Next at theh bottom right of the page
    Populate your “DeviceID” with the Raspberry Pi ID for example as a unique Identifier (aka MAC address). As a naming convention, I prefixe with “SFX_” but you can write whatever you want.

    Declare optional metadata. If not needed, leave empty
    Press Next
    Security : Press “Next” to auto-generate your authentification token
    Press “Add”

    Save your device information (This is very important to copy & paste these information carefully into place where you can retrieve them later on)Organization ID                YOURORGHERE
    Device Type                     Raspberry PiDevice
    Device ID                         SFX_73ED4
    Authentication Method     token
    Authentication Token       YOURTOKENHERE
    Close the window, your device is ready for IBM side.

     

    Now, an API key needs to be generated for future access:

    Select “APPS” from the left side menu

    Click on “api keys” tab
    Click “+ Generate API keys”
    Populate “Comment” : Raspberry Pi access API Keys
    Copy&Paste the “API Key” and “Authentification token” for later on

    Press Finish

  2. Make the servo motor work!

    Download the code here: https://github.com/victordibia/tjwave

    Watch this Video: https://youtu.be/x808LHcmlpE
     
    About Servo Motors and Pulse Width Modulation (PWM)

    Servo motors are used in remote control vehicles and robotics. Most servo motors are not continuous;
    that is, they cannot rotate all the way around but rather just over an angle of about 180 degrees.The position of the servo motor is set by the length of a pulse. The servo expects to receive a pulse at least every 20 milliseconds. If that pulse is high for 1 millisecond, the servo angle will be zero; if it is 1.5 milliseconds, it will be at its center position; and if it is 2 milliseconds, it will be at 180 degrees. Depending on the library you chose to use in generation your pulse width modulation signal, there are various ways to control your servo by setting a duty cycle which determines the pulse frequency.

    On a raspberry Pi, PWM is available on a dedicated hardware pin GPIO Pin (GPIO18, Pin 12). Sometimes, when you have multiple devices that need PWM (e.g. LEDs), you can have software PWM made available on any other pin. In this instructable, we use the dedicated hardware PWM pin for our RGB LED, and use software PWM for the servo.

    Wiring Your Servo Motor

    RaspPi_Pin_Chart

    Your servo motor has three wires – Power, Ground and Data in. In this recipe I use the Tower Pro servo motor and the wires are as follows – Red (Power), Brown (Ground), Yellow (Data in).

    For this recipe, a software PWM library is used to control the servo motor, and I wire my setup as follows.

    Red (+5v, Pin 2)
    Brown (Ground, Pin 14)
    Yellow (Data in, Pin 26, GPIO7 )
    Note: In the code, you can always change the pins used.

  3. Use Node.red to create a flow

    Use node.red to create the flow you would like to open and close the package delivery system which you mount on the drone.

    Ours looked like the image below.

    Create your IoT flow
    This section describes how to create the flow that will drive the integration logic.

    Create a flow:

    Connect to IBM Bluemix : https://console.ng.bluemix.net
    Go to CATALOG on to top menu bar
    Select “node-red” to filter the offering
    Select “Node-Red Starter”

    Populate your Application section and press “Create”

    After a while, the Node-Red service should be up and running

    View your App using the following Menu and selecting your App URL

    Click on “Go To your Node-RED flow Editor”

     

    Notice that your App is open based on your URL (http://Raspberrycdrapp.mybluemix.net)
     

    Now, it is time to build the integration flow:

    Drag&drop an “IBM IoT” node and configure as followSelect “API Key” for Authentication
    Use the Pen to declare an API Key using the one your created before
    Populate API Key and API Token fields
    Press Add button

    Change the Name to “Raspberry IoT” for example
    Press Done
     

    Complete the flow

    Drag&drop a “Debug” node and link it

    Click on “Deploy”
    In the flow, “Debug” should be ON (green) and “Raspberry IoT” should be connected (green). If there is an issue, check you API Key params.
    Click on “Debug” tab on the right side to display future log info

    Slide3

  4. Create a web app on Bluemix!

    This can be loaded in any web browser and we used it to open and close the package delivery system mounted on the drone.

    You can use Node.ui or Freeboard to create a webpage which allows you to create a button to inderact with the flow.

     

    You can get started by installing node-red-ui, as we did, into your node.red instance on Bluemix by following the tutorial here: https://developer.ibm.com/recipes/tutorials/ui-dashboard-for-iot-device-data-using-node-red/

     

    Once it's installed you simply pull the user interface data from the node.red flow (as shown in the image in our previous step).

    Slide4

  5. Execute the code from the Raspberry Pi

    Slide5

  6. Go Fly with your Package Delivery System!

    Deliver_Box_IBM

    Delivery_Box_Close.

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