Makerson the Robot
@ September 12, 2010
Navigate around via ultrasound, aka he avoids obstacles.
Cost to build:
$123
URL to more information:
- Actuators / output devices: 2x Solarbotics GM9 with Solarbotics wheels
- Control method: Arduino Duemilanove
- CPU: Atmel ATmega328
- Power source: 1X 9V 6X AA batteries
- Programming language: Modified C++
- Sensors / input devices: PING))) Ultrasonic sensor
- Target environment: indoor only
My first robot with very little to show. He's built on the top of a container and uses code I got off the internet. I want to learn more about programming and eventually make my own code for him. My next add-on will be bump switches for use when Makerson gets stuck because of the blind spot of the Parallax PING)). OH, and his name was inspired by make magazine, my favorite. I think he's pretty good for a fourteen year old to build. Please comment on how to make my code better and how to add bump switches. The code is in the link.
@ Wed, 2010-09-15 02:05
bump switches
Bump switches are very easy. You choose 2 pins, for the left and right bump sensor. Let's say 2 and 3.
In the beginning of the code, you define variables:
const int left_bumpsensor=2;
const int right_bumpsensor=3;
Then, in the setup function, you make your pins input:
pinMode(right_bumpsensor, INPUT);
pinMode(left_bumpsensor, INPUT);
You connect two ~10K resistors from pin 2 and pin 3 to ground. You connect the switches from the pins to +5v while still having the resistors.
In the loop code, you read the status of every switch with:
digitalRead(left_bumpsensor);
or digitalRead(right_bumpsensor);
I give an example:
left_bump_state = digitalRead(left_bumpsensor);
right_bump_state = digitalRead(right_bumpsensor);
// if the left bumpswitch has made contact, we shut off the right motor. this will make the thing go right
if (left_bump_state == HIGH)
digitalWrite(right_motor_pin, LOW);
else
digitalWrite(right_motor_pin, HIGH);
// if the right bumpswitch has made contact, we shut off the left motor. this will make the thing go left
if (right_bump_state == HIGH)
digitalWrite(left_motor_pin, LOW);
else
digitalWrite(left_motor_pin, HIGH);
Modify this to whatever fits your code. If you still have difficulties, paste your code here.
@ Wed, 2010-09-15 02:15
Thanks
That is totally what I needed. thanks. Do I need to be concerned with debouncing?
@ Wed, 2010-09-15 02:37
error
I tried to give it a go, but here's what i got. I have no idea what this means
In function 'void loop()':
error: 'right_bump_state' was not declared in this scope
The code:
const int left_bumpsensor=2;
const int right_bumpsensor=3;
#define leftDir1 7 // Left motor direction 1, to AIn1.
#define leftDir2 6 // Left motor direction 2, to AIn2.
#define rightDir1 5 // Right motor direction 1, to BIn1.
#define rightDir2 4 // Right motor direction 2, to BIn2.
void setup()
{
pinMode(right_bumpsensor, INPUT);
pinMode(left_bumpsensor, INPUT);
pinMode(leftDir1, OUTPUT); // Set motor direction pins as outputs.
pinMode(leftDir2, OUTPUT);
pinMode(rightDir1, OUTPUT);
pinMode(rightDir2, OUTPUT);
Serial.begin(9600);
}
void loop()
{
digitalRead(right_bumpsensor);
right_bump_state = digitalRead(right_bumpsensor)
// if the right bumpswitch has made contact, we shut off the left motor. this will make the thing go left
if (right_bump_state == HIGH)
digitalWrite(left_motor_pin, LOW);
else
digitalWrite(left_motor_pin, HIGH);
}
Thats what i wrote. Please help
@ Wed, 2010-09-15 02:48
You need to declare the
You need to declare the variable right_bump_state before you use it. Place it up at the top of your program above the void setup() line.
Something like:
int right_bump_state;
@ Wed, 2010-09-15 06:58
bool
It better be:
bool right_bumpstate;
Bools can be only false or true, and they take much less footprint in the memory than a int.
@ Wed, 2010-09-15 02:40
The code i have been using
This is the code i have been using:
/*
* 06_Object_Avoidance
*
* Makey robot roams around, while avoiding objects
* sensed with the Ping ultrasonic rangefinder.
*
* Makey Robot, MAKE Magazine, Volume 19, p. 77
* Created: June 2009 Kris Magri
* Modified:
*
*/
#define pingPin 9 // Ping ultrasonic sensor on pin D9.
#define leftDir1 7 // Left motor direction 1, to AIn1.
#define leftDir2 6 // Left motor direction 2, to AIn2.
#define rightDir1 5 // Right motor direction 1, to BIn1.
#define rightDir2 4 // Right motor direction 2, to BIn2.
#define BOUNDARY 35 // (cm) Avoid objects closer than 35cm.
#define INTERVAL 25 // (ms) Interval between distance readings.
// setup
// Set motor pins as OUTPUTS, initialize Serial
void setup()
{
pinMode(leftDir1, OUTPUT); // Set motor direction pins as outputs.
pinMode(leftDir2, OUTPUT);
pinMode(rightDir1, OUTPUT);
pinMode(rightDir2, OUTPUT);
Serial.begin(9600);
}
// Main program
// Roam around while avoiding objects.
//
// Set motors to move forward,
// Take distance readings over and over,
// as long as no objects are too close (determined by BOUNDARY).
// If object is too close, avoid it -- back up and turn.
// Repeat.
void loop()
{
long distance; // Distance reading from rangefinder.
forward(); // Robot moves forward continuously.
do
{
distance = readDistance(); // Take a distance reading.
Serial.println(distance); // Print it out.
delay(INTERVAL); // Delay between readings.
}
while(distance >= BOUNDARY); // Loop while no objects close-by.
// Robot has sensed a nearby object and exited the while loop.
// Take evasive action to avoid object.
backward(); // Move backward 500ms.
delay(500);
rightTurn(300); // Turn right for 300ms.
} // end Main program
// forward
//
// Move robot forward by setting both wheels forward.
// Will persist until something else changes the
// motors' directions.
void forward()
{
digitalWrite(leftDir1, LOW); // Left motor forward.
digitalWrite(leftDir2, HIGH);
digitalWrite(rightDir1, LOW); // Right motor forward.
digitalWrite(rightDir2, HIGH);
}
// backward
//
// Move robot backward by setting both wheels backward.
// Will persist until something else changes the
// motors' directions.
void backward()
{
digitalWrite(leftDir1, HIGH); // Left motor backward.
digitalWrite(leftDir2, LOW);
digitalWrite(rightDir1, HIGH); // Right motor backward.
digitalWrite(rightDir2, LOW);
}
// rightTurn
//
// Turn robot to right by moving wheels in opposite directions.
// Amount of turning is determined by duration argument (ms).
void rightTurn(int duration)
{
digitalWrite(leftDir1, HIGH); // Left motor backward.
digitalWrite(leftDir2, LOW);
digitalWrite(rightDir1, LOW); // Right motor forward.
digitalWrite(rightDir2, HIGH);
delay(duration); // Turning time (ms).
}
// readDistance
// Take a distance reading from Ping ultrasonic rangefinder.
// from http://arduino.cc/en/Tutorial/Ping?from=Tutorial.UltrasoundSensor
long readDistance()
{
long duration, inches, cm;
// The Ping is triggered by a HIGH pulse of 2 or more microseconds.
// We give a short LOW pulse beforehand to ensure a clean HIGH pulse.
pinMode(pingPin, OUTPUT);
digitalWrite(pingPin, LOW);
delayMicroseconds(2);
digitalWrite(pingPin, HIGH);
delayMicroseconds(5);
digitalWrite(pingPin, LOW);
// The same pin is used to read the signal from the Ping: a HIGH
// pulse whose duration is the time (in microseconds) from the sending
// of the ping to the reception of its echo off an object.
pinMode(pingPin, INPUT);
duration = pulseIn(pingPin, HIGH);
// Convert the time into a distance.
cm = microsecondsToCentimeters(duration);
return(cm);
}
long microsecondsToCentimeters(long microseconds)
{
// The speed of sound is 340 m/s or 29 microseconds per centimeter.
// The ping travels out and back, so to find the distance of the
// object we take half of the distance traveled.
return microseconds / 29 / 2;
}
@ Wed, 2010-09-15 01:12
its in the link!
check out the link at the top of my bots profile, it goes to make magazine where i got the project
@ Tue, 2010-09-14 18:15
Code
Please can you add your code as an attachment and I will be glad to have a look over to highlight any improvements you may be able to make.
Dan