How-To Intel® IoT Code Samples: Line following robot

Introduction

This line following robot application is part of a series of how-to Intel® IoT code sample exercises using the Intel® IoT Developer Kit, Intel® Edison development platform, cloud platforms, APIs, and other technologies.

From this exercise, developers will learn how to:

• Connect the Intel® Edison development platform, a computing platform designed for prototyping and producing IoT and wearable computing products.
• Interface with the Intel® Edison platform IO and sensor repository using MRAA and UPM from the Intel® IoT Developer Kit, a complete hardware and software solution to help developers explore the IoT and implement innovative projects.
• Run this code sample in Intel® XDK IoT Edition, an IDE for creating applications that interact with sensors and actuators, enabling a quick start for developing software for the Intel® Edison or Intel® Galileo board.
• Store line detection data using Azure Redis Cache* from Microsoft* Azure*, cloud services for connecting IoT solutions including data analysis, machine learning, and a variety of productivity tools to simplify the process of connecting your sensors to the cloud and getting your IoT project up and running quickly.

What it is

Using an Intel® Edison board, this project lets you create a line following robot that:

• Continuously checks the line finder sensor;
• Moves forward if on the line, using the stepper motors;
• Tries to pivot to find the line if not on it, using the stepper motors;
• Logs events from the line finder sensor, using cloud-based data storage.

How it works

The line finder robot uses the two attached motors to attempt to follow a line, keeping track of it with the line finder sensor. If on the line, it moves forward. Otherwise, it pivots in place, trying to locate it using the line finder sensor.

Optionally, it can store system events using the Intel® IoT Example Datastore running in your own Microsoft* Azure* account.

Hardware requirements

Grove* Robotics Kit containing:

1. Intel® Edison with an Arduino* breakout board
2. Grove* Line Finder
3. Stepper Motor Controller & Stepper Motor (x2)

Software requirements

1. Intel® XDK IoT Edition
2. Microsoft* Azure* account

How to set up

To begin, clone the Intel® IoT Examples repository with Git* on your computer as follows:

$ git clone https://github.com/intel-iot-devkit/how-to-code-samples.git

Want to download a .zip file? In your web browser, go to https://github.com/intel-iot-devkit/how-to-code-samples and click the Download ZIP button at the lower right. Once the .zip file is downloaded, uncompress it, and then use the files in the directory for this example.

Adding the program to Intel® XDK IoT Edition

In Intel® XDK IoT Edition, select Import Your Node.js Project:

Then, navigate to the directory where the example project exists, and select it:

You need to connect to your Intel® Edison board from your computer to send code to it.

Click the IoT Device menu at the bottom left. If your Intel® Edison is automatically recognized, select it.

Otherwise, select Add Manual Connection. In the Address field, type 192.168.2.15. In the Port field, type 58888. Click Connect to save your connection.

Installing the program manually on Intel® Edison

Alternatively, you can set up the code manually on the Intel® Edison board.

Clone the Intel® IoT Examples repository to your Intel® Edison board after you establish an SSH connection to it, as follows:

$ git clone https://github.com/intel-iot-devkit/how-to-code-samples.git

Then, navigate to the directory with this example.

To install Git* on Intel® Edison, if you don’t have it yet, establish an SSH connection to the board and run the following command:

$ opkg install git

Connecting the Grove* sensors

You need to have a Grove* Shield connected to an Arduino*-compatible breakout board to plug all the Grove* devices into the Grove* Shield. Make sure you have the tiny VCC switch on the Grove* Shield set to 5V.

You need to power Intel® Edison with the external power adapter that comes with your starter kit, or substitute it with an external 12V 1.5A power supply. You can also use an external battery, such as a 5V USB battery.

In addition, you need a breadboard and an extra 5V power supply to provide power to both motors. Note: you need a separate battery or power supply for the motors. You cannot use the same power supply for both the Intel® Edison board and the motors, so you need either 2 batteries or 2 power supplies in total.

1. Plug each of the stepper motor controllers into 4 pins on the Arduino* breakout board for it to be able to be controlled. Connect stepper motor controller #1 to pins 4, 5, 6, and 7. Connect stepper motor controller #2 to pins 9, 10, 11, and 12. Connect both controllers to ground (GND), to the 5V power coming from the Arduino* breakout board (VCC), and to the separate 5V power for the motors (VM).

2. Plug one end of a Grove* cable into the Grove* Line Finder, and connect the other end to the D2 port on the Grove* Shield.

Manual Intel® Edison setup

If you're running this code on your Intel® Edison manually, you need to install some dependencies.

To obtain the Node.js* modules needed for this example to execute on Intel® Edison, run the following command:

npm install

Microsoft* Azure* server setup

Optionally, you can store the data generated by this example program in a backend database deployed using Microsoft* Azure*, Node.js*, and a Redis* data store.

For information on how to set up your own cloud data server, go to:

https://github.com/intel-iot-devkit/intel-iot-examples-datastore

Configuring the example

To configure the example for the optional Microsoft* Azure* data store, change the SERVER and AUTH_TOKEN keys in the config.json file as follows:

{"SERVER": "http://intel-examples.azurewebsites.net/logger/line-follower","AUTH_TOKEN": "s3cr3t"
}

Running the program using Intel® XDK IoT Edition

When you're ready to run the example, make sure you saved all the files.

Click the Upload icon to upload the files to the Intel® Edison board.

Click the Run icon at the bottom of Intel® XDK IoT Edition. This runs the code on Intel® Edison.

If you made changes to the code, click Upload and Run. This runs the latest code with your changes on Intel® Edison.

You will see output similar to the above when the program is running.

Running the program manually

To run the example manually on Intel® Edison, establish an SSH connection to the board and execute the following command:

node index.js

Determining the Intel® Edison IP address

You can determine what IP address Intel® Edison is connected to by running the following command:

ip addr show | grep wlan

You will see the output similar to the following:

3: wlan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    inet 192.168.1.13/24 brd 192.168.1.255 scope global wlan0

The IP address is shown next to inet. In the example above, the IP address is 192.168.1.13.

For a complete list of How-To Intel® IoT Code Samples, go to Intel® Developer Zone.

For more details about this code sample, go to GitHub*.