AnyWay + NXTBee = Remote Controlled Segway

Anyway in Hallway.

Building on the AnyWay Segway project, we’ve added a few things to make it remote controlled.  We use the NXTBee, along with an XBee computer adapter, to control the direction the AnyWay goes with a computer.  It’s like a remote controlled car, but it’s a Segway.  Made of LEGOs.

Building instructions, computer code, pictures, and video are all here!

Laurens Valk did a fantastic job making the AnyWay, a self-balancing segway made of LEGO MINDSTORMS NXT.  We immediately thought, “Hey, let’s control it with our computer!”

The AnyWay uses the dIMU to balance.  Reading the gyroscope sensor built in, it keeps the AnyWay standing straight up. The code is easy to modify, and building the AnyWay is really easy.

Next, we slapped on a NXTBee for radio communication.  A lot has been said about the NXTBee:  it’s high speed, easy to configure communications for the LEGO MINDSTORMS NXT.  You can read more about it on our web page or on our blog.

Xbee Explorer: Ready to Rock

Finally, we needed a way to communicate from the NXTBee to the computer.  Sending signals to and from the computer is really easy if you have a Sparkfun Xbee Explorer USB.  You can pick one up on the Sparkfun website.  We are thinking about carrying the XBee Explorer in our store too, so let us know if you want one. (We will do a separate post on the Xbee Explorer and computer communication soon).

Xbee Explorer, Unmasked.

We modified the RobotC version of the AnyWay to add the NXTBee functionality in.  We send our commands through Digi’s XCTU, a terminal program that’s free from Digi and can send commands through the XBee.  To send the AnyWay forward, you hit ‘w’, and ‘s’ for stop, ‘z’ for backup, and ‘a’ and ‘d’ to turn left and right.

We have posted the example code below the videos just below.  Enjoy!

You can find the modified Source Code Below. Modify it as you see fit!
[sourcecode language=”cpp”] /*******INFO*******

LEGO MINDSTORMS NXT Segway program Example

Example #1: Segway-Explanation(Wall-Avoidance).c Wall avoidance program for a LEGO NXT Segway
(Includes description of commands to control Segway movement)

Author: Laurens Valk (laurensvalk.com)

License: Use the examples as you like, but give credit to the original author.
See driver file for more details.

Requirements – Hardware:
– Assembled Segway with LEGO MINDSTORMS NXT parts: http://www.laurensvalk.com
– LEGO MINDSTORMS NXT compatible Gyroscope (see segway-driver-lv.h for details)

Requirements – Software:
– RobotC: http://robotc.net/
– RobotC Driver Suite version 2.3 or later: http://botbench.com/blog/robotc-driver-suite/
– segway-driver-lv.h: Included in this package, or find it at http://www.laurensvalk.com

Version:
– 0.9

***************/

//Adjust these lines to match your Segway Setup

//Choose 1 for Dexter Industries Gyro (dIMU) or 0 for HiTechnic Gyro
const int your_gyro_sensor = 1;

//Choose gyro sensor port (S1, S2, S3, S4)
const tSensors Gyro = S2;

//Choose the radius of your wheel. That’s half the diameter, measured in meters!
//Choose 0.021 for NXT2.0 wheels; 0.027 for NXT1.0 wheels;
const float your_wheel_radius = 0.021;
///////

//If you’re not using the dIMU, you may remove this #include line
//Change the location of the driver file below if you installed your drivers elsewhere!
#include "C:Program Files (x86)Robotics Academy3rd Party Driversrdpartyrobotcdr-v2.1driversDIMU-driver.h"
#include "segway-driver-lv.h"
//#include "DIMU-driver.h"

task main()
{
//nxtEnableHSPort(); //Enable High Speed Port #4
//nxtSetHSBaudRate(9600); //Xbee Default Speed
//nxtHS_Mode = hsRawMode; //Set to Raw Mode (vs. Master/Slave Mode)

//short bytesRead;
ubyte incomingData;

StartTask(balancing);
while(starting_balancing_task){}
//It’s that simple – now go program something cool below!

/*Here’s how to control the Segway.

MOVING AROUND
– Adjust <steering> to steer.
steering = 0 ; //Go Straight
steering = 10 ; //Turn Right
steering = 17; //Turn Right quicklier
steering = -10; //Turn Left
etc…

– Adjust <speed> for moving forward and backwards.
Its value is the motor power that the robot will attempt to maintain

speed = 0; //Stand still
speed = -20 ; //Go backward at 20% of motor power
speed = 50; //Go forward at half of maximum motor power (recommended)
etc…

– Adjust <acceleration> to change how quickly your robot will reach a certain speed.

acceleration = 60; means that if your current speed is -20 and you change it
to 40, it will take 1 seconds to get to that speed. You don’t need to change this
in your program, just set it once. Setting <acceleration = 60;> is recommended.

TIPS & TRICKS
– Don’t mess with motor B and C!
– You can read the motor encoders like you would normally do. Just don’t reset them.
– Speed sets the motor speed – This means you go faster if you use bigger wheels.
*/

//////////////////////////////////////////////
//
// EXAMPLE #1: Wall avoidance

ubyte BytesRead[8];

const tSensors Sonar = S4;
SensorType[Sonar] = sensorSONAR;

acceleration = 60;
steering = 0;
wait1Msec(3000);//We wait three seconds just to be sure we’re up and running
PlaySound(soundBeepBeep);

speed = 50;

//Every 100 ms, we check if the sensor has spotted anything closer than 60 cm.
//When so, the robot goes backwards, turns, and continues its way. Note how the
//speed and steering variables are used to manipulate the robot’s movement.
eraseDisplay();

nxtEnableHSPort(); //Enable High Speed Port #4
nxtSetHSBaudRate(9600); //Xbee Default Speed
nxtHS_Mode = hsRawMode; //Set to Raw Mode (vs. Master/Slave Mode)

while(true)
{
if(nxtGetAvailHSBytes()) //Check to see if we have any data coming in
{
if(nxtGetAvailHSBytes()) //Ask for the data, save to "incomingDate".
{
nxtReadRawHS(incomingData, 1);
//If we actually got data, display it to the LCD
nxtDisplayTextLine(1, "Receive: %c, %i", (char)incomingData, (int)incomingData);
if((char)incomingData == ‘w’){steering = 0; speed = 50;} // Go forward, straight
if((char)incomingData == ‘a’){steering = steering + 10;} // Turn Left
if((char)incomingData == ‘z’){steering = 0; speed = -50;} // Go backwards
if((char)incomingData == ‘d’){steering = steering -10;} // Turn Right
if((char)incomingData == ‘s’){steering = 0; speed = 0;} // Stop
if((char)incomingData == ‘+’){speed = speed+10;} // Increase Speed
if((char)incomingData == ‘-‘){speed = speed-10;} // Decrease Speed
}
}
else //No Data, Wait a little before trying again
{
wait1Msec(25); //Wait 25ms before checking again.
}
}

}