Raspberry Pi Forums

Posted: **Sat Sep 12, 2015 9:00 pm**

Hi;

I have a posted a couple of threads around this forum and the help I have received has helped me to successfully build my Robot.

Here is the not yet finished Instructable:
http://www.instructables.com/id/Raspber ... ous-Robot/

It is a Raspberry Pi / Arduino Hybrid, the Arduino (Nano AT-Mega328P) drives the Motors, Ultrasonic Sensor and a Servo that the Sensor is mounted on. The Nano is connected to a Raspberry Pi as a Slave receiving commands via an i2c Serial Interface. The Raspberry Pi acts as the i2c Master and serves a Web Page using WebIOPi on which is a control panel to control the Robot wirelessly over WiFi. The Robot also has a USB Web Camera mounted on it which streams video using MJPG-Streamer at about 20fps to the control panel web page.

I have recently changed the Sketch code so that the Robot also has a timer function that puts it into Autonomous mode if does not receive any commands after a given time period and it detects movement (not confirmed that this is working yet).

Problems / Required Upgrades
What I need help with now is:
1. Forward and backwards works fine (could be a little more incremental) but I need to fine tune turning left and right, currently when clicking left or right the Robot spins almost 180 degrees, how do I adjust this (In Arduino Sketch).

2. For debugging how do I get the Serial messages in Sketch to appear on my Web Page, later they may be pushed to an onboard LCD panel.

3. My AutonomousMode and Auto_Navigate modules in Sketch have been created without any external assistance and may be wrong? Such as sending serial data back to the Pi when movement is detected, the code on the python end to play an audio message has not yet been added.

I appreciate most of this is Arduino Sketch questions but I thought I'd throw it out there.

Thanks

Here's the Python:

Code: Select all

# Python programme for controlling Arduino Nano connected to a Raspberry Pi using i2c serial communication
# inspiration for the i2c element from Oscar laing's Blog
# http://blog.oscarliang.net/raspberry-pi-arduino-connected-i2c
# Commands sent to Raspberry Pi over a web page using webiopi
# Prior to running this program you must start the pigpio daemon if using the Pi GPIO
# by either entering pigpiod at a command prompt or running it automatically at startup 
# as a CRON job
# If you recieve a module import error no module named smbus ensure version of smbus
# and WebIOPi Python match

#/usr/bin/env python

import webiopi # Import webiopi - software to communicate with a Rapsberry Pi over a web interface
import smbus as smbus
import time
import os

# Uncomment the following two lines if using the Pi GPIO
#import pigpio # pigpio is a custom module for controlling GPIO pins
# pi = pigpio.pi #declare psuedo for pigpio commands

bus = smbus.SMBus(1) # For RPI version 1 use "bus = smbus.SMBus(0)"

# Setup i2C communication address (must be the same as address set on Arduino
address = 0x04

def writeNumber(value):
   	bus.write_byte(address, value)
	# bus.write_byte_data(address, 0, value)
   	return -1

def readNumber():
	number = bus.read_byte_data(address, 1)
	return number
		
#@webiopi.macro
def stop():
        number = 0
        writeNumber(number)
        time.sleep(1)
        
#@webiopi.macro
def forward():
        number = 1
        writeNumber(number)
        time.sleep(1)
        
#@webiopi.macro
def left():
        number = 2
        writeNumber(number)
        time.sleep(1)
        
#@webiopi.macro
def right():
        number = 3
        writeNumber(number)
        time.sleep(1)
        
#@webiopi.macro
def backward():
        number = 4
        writeNumber(number)
        time.sleep(1)

#@webiopi.macro
def servo_centre():
        number = 5
        writeNumber(number)
        time.sleep(1)

#@webiopi.macro
def servo_left():
        number = 6
        writeNumber(number)
        time.sleep(1)

#@webiopi.macro
def servo_right():
        number = 7
        writeNumber(number)
        time.sleep(1)        
        
#@webiopi.macro
def led_on():
	number = 8
	writeNumber(number)
	time.sleep(1)
	
#@webiopi.macro
def led_off():
	number = 9
	writeNumber(number)
	time.sleep(1)
	
# Start the webiopi server
server = webiopi.Server(port=8000, login="Hammerstein", password="Hammerstein")

# Start the webcam video stream
os.system("streamer.sh")

# Register the macros
server.addMacro(stop)
server.addMacro(forward)
server.addMacro(left)
server.addMacro(right)
server.addMacro(backward)
server.addMacro(stop)
server.addMacro(servo_centre)
server.addMacro(servo_left)
server.addMacro(servo_right)
server.addMacro(led_on)
server.addMacro(led_off)

# Run default loop

webiopi.runLoop()

# Cleanly stop the server
server.stop()

Here's the Html:

Code: Select all

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta name="viewport" content = "height = device-height, width = 420, user-scalable = no" /> 
<title>Hammerstein_Mobile_Control_Panel</title>
<script type="text/javascript" src="/webiopi.js"></script>
<script type="text/javascript">

   	function stop() {
   	webiopi().callMacro("stop");
   	}
   
   	function forward() {
       webiopi().callMacro("forward");
    }

   	function left() {
       webiopi().callMacro("left");
    }

   	function right() {
       webiopi().callMacro("right");
    }

   	function backward() {
       webiopi().callMacro("backward");
    }

	function servo_centre() {
		webiopi().callMacro("servo_centre");
	}	
   	
   	function servo_left() {
       webiopi().callMacro("servo_left");
    }

	function servo_right() {
		webiopi().callMacro("servo_right");
	}
		
   function LED_On() {
       webiopi().callMacro("led_on");
    }
   
   function LED_Off() {
       webiopi().callMacro("led_off");
    }	

</script>


<style type="text/css">

.myButton {
   -moz-box-shadow:inset 0px 1px 0px 0px #ffffff;
   -webkit-box-shadow:inset 0px 1px 0px 0px #ffffff;
   box-shadow:inset 0px 1px 0px 0px #ffffff;
   background:-webkit-gradient(linear, left top, left bottom, color-stop(0.05, #ffffff), color-stop(1, #f6f6f6));
   background:-moz-linear-gradient(top, #ffffff 5%, #f6f6f6 100%);
   background:-webkit-linear-gradient(top, #ffffff 5%, #f6f6f6 100%);
   background:-o-linear-gradient(top, #ffffff 5%, #f6f6f6 100%);
   background:-ms-linear-gradient(top, #ffffff 5%, #f6f6f6 100%);
   background:linear-gradient(to bottom, #ffffff 5%, #f6f6f6 100%);
   background-color:#ffffff;
   -moz-border-radius:6px;
   -webkit-border-radius:6px;
   border-radius:6px;
   border:1px solid #dcdcdc;
   display:inline-block;
   cursor:pointer;
   color:#666666;
   font-family:Arial;
   font-size:15px;
   font-weight:bold;
   padding:6px 24px;
   text-decoration:none;
   text-shadow:0px 1px 0px #ffffff;
        width: 130px;
        height:30px;
        margin:1px;
}
.myButton:hover {
   background:-webkit-gradient(linear, left top, left bottom, color-stop(0.05, #f6f6f6), color-stop(1, #ffffff));
   background:-moz-linear-gradient(top, #f6f6f6 5%, #ffffff 100%);
   background:-webkit-linear-gradient(top, #f6f6f6 5%, #ffffff 100%);
   background:-o-linear-gradient(top, #f6f6f6 5%, #ffffff 100%);
   background:-ms-linear-gradient(top, #f6f6f6 5%, #ffffff 100%);
   background:linear-gradient(to bottom, #f6f6f6 5%, #ffffff 100%);
   background-color:#f6f6f6;
        padding:6px 24px;
}
.myButton:active {
   color:#ff0000;
        position:relative;
   top:1px;
        padding:6px 24px;
}

</style>

</head>
<body>
<center><h2>Hammerstein Control Panel</h2></center><br>


<center>
<table>
<tr><td colspan=3 align="center"><button class="myButton" onmousedown="forward()" onmouseup="stop()">Forward</button></td></tr>
<tr><td><button class="myButton" type="button" onmousedown="left()" onmouseup="stop()">Left</button></td>
<td><button class="myButton" type="button" onclick="stop()">Stop</button></td>
<td><button class="myButton" type="button" onmousedown="right()" onmouseup="stop()">Right</button></td></tr>
<tr><td colspan=3 align="center"><button class="myButton" type="button" onmousedown="backward()" onmouseup="stop()">Backward</button></td></tr>
<tr><td colspan=3 align="center"><button class="myButton" type="button" onmousedown="LED_On()" onmouseup="LED_Off()">LED_On</button></td></tr>
</table>
</center>

<center><h2>Sensor Control</h2></center><br>
<center>
<table>
<tr><td><button class="myButton" type="button" onclick="servo_left()">Scan Left</button></td>
<td><button class="myButton" type="button" onclick="servo_centre()">Centre</button></td>
<td><button class="myButton" type="button" onclick="servo_right()">Scan Right</button></td></tr>
</table>
</center>

<center><h2>Robo Cam</h2></center>
	<center><img id="streamimage" src="http://192.168.1.87:10088/?action=stream" /></center>
</body>
</html>

Here's the Sketch:

Code: Select all

// Program to set an Arduino as a slave for an i2c connection with a Raspberry Pi
// Controlling a mobile platform (robot) with manual and autonomous modes  
// Connections are Arduino Pin A5 to RPi SDA Arduino Pin A6 to RPi SCL
// Inspiration for i2c from Oscar Laing's Blog http://blog.oscarliang.net/raspberry-pi-arduino-connected-i2c

//Setup libraries
#include <Wire.h>
#include <Servo.h>

//Set Arduino as i2c slave and define the Serial bus address
#define SLAVE_ADDRESS 0x04

//Set variables for serial communication
int number = 0; // Number determines which command to run 
int state = 0; // Was used to check High and Low (not yet used)

//Setup Ultrasonic Sensor Pins
#define trigPin 13
#define echoPin 12

//Defines for reading distances and collision avoidance when in autonomous mode (when setup) 
#define microsecondsToCentimeters(microseconds) (unsigned long)microseconds / 29.1 / 2.0
#define Min_Action_Distance 40 // Set maximum allowaable distance to obstacle

//Time delays for motors and servos if required
#define ServoMoveDelay 2000

//Setup motor controller pins for L298N
//Right Motor
int enA = 11;
int in1 = 8;
int in2 = 7;

//Left Motor
int enB = 10;
int in3 = 6;
int in4 = 5;

//Setup LED test pin
int Led = 3;

//Give servos a logical designation
Servo sensor_servo;

//Setup variables
byte scan_pos = 0;
byte sweep_pos = 0;
byte pos_index = 90;
unsigned long left_distance, right_distance, forward_distance;
unsigned int duration;
unsigned int distance;
//unsigned int FrontDistance;
//unsigned int LeftDistance;
//unsigned int RightDistance;
unsigned long lastDataReceivedMillis; 
unsigned long maxGap = 10000;
unsigned int mode;

void setup() {
  delay(1000); // Sets a short delay after switching on
  Serial.begin(9600); // Start serial for output debugging
  Wire.begin(SLAVE_ADDRESS); // Initialise i2c as slave
  Wire.onReceive(receiveData); //Define callbacks for i2c communication
  Wire.onRequest(sendData); //Define callbacks for i2c communication
  
  //Setup the servo
  sensor_servo.attach(2); //Attaches the servo to pin 2 of the Nano
  sensor_servo.write(90); //Set the servo to face front
  scan_pos = 90;
  
  //Below set all the pin modes as OUTPUT as they will all be outputting data
  //Set modes for distance sensor pins 
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  
  //Set modes for motor controller pins
  pinMode(enA, OUTPUT);   
  pinMode(enB, OUTPUT);   
  pinMode(in1, OUTPUT);   
  pinMode(in2, OUTPUT);   
  pinMode(in3, OUTPUT);   
  pinMode(in4, OUTPUT);

  //Set mode for Led test pin
  pinMode(Led, OUTPUT);

  // Message to serial monitor declaring that robot is ready
  Serial.println("Hammerstein Ready!");
  mode = 0;
}

void loop() { 
  ping();
  //scan(); 
  //get_battery(); 
  while(true)
  {
    if (Wire.available())
    {
    mode = 0;
    Serial.println("Manual Mode");  
    continue;
    }
    else if(millis() - lastDataReceivedMillis >= maxGap)
    {
      if (mode == 0) Serial.println("Switching to autonomous mode in 5 seconds");
      delay(5000);
      mode = 1;
      AutonomousMode();
    }
   
  }
}


// Callback for received data
void receiveData(int byteCount) {
  
  while(Wire.available()) {
    number = Wire.read();
    Serial.println("data received: ");
    Serial.println(number);
    
    if (number == 0) {
      Stop();
    } 
    if (number == 1) {
      Forward();
    }
    if (number == 2) {
      Left();
    }
    if (number == 3) {
      Right();
    }
    if (number == 4) {
      Backward();
    }
    if (number == 5) {
      Servo_Centre();
    }
    if (number == 6) {
      Servo_Left();
    }
    if (number == 7) {
      Servo_Right();
    }
    if (number == 8) {
      led_on();
    }
    if (number == 9) {
      led_off();
    }
    //if (number == 10) { //Need to create a function in the python code to send command 10
    //  Auto_navigate();
    //}
  }
}

// Callback for sending data
void sendData() {
  Wire.write(number);
}

void AutonomousMode() //08/09/2015 - autonomous mode set to detect movement 
{
  Serial.println("Now in autonomous mode");
  unsigned long motion_detect_left, motion_detect_right, motion_detect_forward;
  if (mode == 1) //Only execute if in autonomous mode
  {
    Scan();
    motion_detect_left = left_distance;
    motion_detect_right = right_distance;
    motion_detect_forward = forward_distance;
    Scan();
    if (motion_detect_left == left_distance && motion_detect_right == right_distance && motion_detect_forward == forward_distance)
    {
      Stop(); 
    }
    else
    {
      Serial.println("Obstacle detected");
      number = 1;
      Auto_navigate();
      sendData(number); //Send content of variable 'number' to inform the Raspberry Pi that an obstacle has been detected and to say something
    }
  }
}

void Auto_navigate()
{
  do
  {
    Serial.println("Auto navigating environment");
    Scan();
    if (forward_distance > Min_Action_Distance)
    {
      Forward(); 
    }
    else
    {
      Stop();
      if (left_distance > right_distance && left_distance > Min_Action_Distance)
      {
        Left();
        Forward();
      }
      else
      {
        Right();
        if (right_distance > Min_Action_Distance)
        {
          Forward();
        }
      }
    }
   } while (mode == 1);
}

 
void get_battery()
//{
//  int BatteryValue = analogRead(0);
//  float voltage = BatteryValue * (7.2 / 1023.0);
//  Serial.println(voltage);
//}

{
  int raw = analogRead(0);
  float val = fmap(raw, 0, 1023, 0.00, 7.20);
  Serial.println(val);
}

float fmap(float x, float in_min, float in_max, float out_min, float out_max)
{
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}

void Scan() //Print routines included for debugging 
{
  //Position sensor servo to the right 
  if (scan_pos != 20) 
  { //Only move the servo if it is not already in position
    sensor_servo.write (20);
  }
  delay (ServoMoveDelay);
  Serial.println("Sensor at 20 degrees..."); 
  ping(); //Read the sensor
  left_distance = distance;
  Serial.println("Clear right for  "); 
  Serial.print(left_distance); 
  Serial.println(" cm"); 
  
  //Position sensor servo to the front
  if (scan_pos != 90) //Only move the servo if it is not already in position
  { 
    sensor_servo.write(90);
  }
  delay (ServoMoveDelay);
  Serial.println("Servo at 90 degrees front...");
  ping(); //Read the sensor
  forward_distance = distance;
  Serial.println("Clear forward for  "); 
  Serial.print(forward_distance); 
  Serial.println(" cm"); 
  
  //Position sensor servo to the left 
  if (scan_pos != 160) //Only move the servo if it is not already in position
  { 
    sensor_servo.write (160);
  }
  delay (ServoMoveDelay);
  Serial.println("Sensor at 160 degrees...");
  ping(); //Read the sensor
  Serial.println("Clear left for  ");
  Serial.print(left_distance);  
  Serial.println(" cm"); 

  if (scan_pos != 90) //Only move the servo if it is not already in position
  { 
    sensor_servo.write(90);
  }
}

void Servo_Sweep() //This function tells the robot to scan for obstacles - redundant for time being  
{
  if (sweep_pos <=0)
  {
    pos_index = 20;
  }
  else if (sweep_pos >=180) 
  {
    pos_index = -20;
  }
  Serial.print ("pos_index = ");
  Serial.println(pos_index);
  sweep_pos += pos_index;
  Serial.print("sweep_pos = ");
  Serial.println(sweep_pos);
  sensor_servo.write (sweep_pos);
}

void Servo_Centre() //Manual control of sensor servo 
{
  Serial.println("");
  Serial.println("Scanning ahead");
  if (sweep_pos != 90)
  {
    sensor_servo.write(90);
    sweep_pos = 90;
    ping();
    //distance = ping();
    Serial.println("Distance ahead = ");
    Serial.print(distance);
    Serial.print(" cm");
  }
}

void Servo_Right() //Manual control of sensor servo 
{
  Serial.println("");
  Serial.println("Scanning right");
  if (sweep_pos != 20) 
  {
    sensor_servo.write(20);
    sweep_pos = 20;
    ping();
    //distance = ping();
    Serial.println("Distance right = ");
    Serial.print(distance);
    Serial.print(" cm"); 
  }
}

void Servo_Left() //Manual control of sensor servo 
{
  Serial.println("");
  Serial.println("Scanning Left");
  if (sweep_pos != 160) 
  {
    sensor_servo.write(160);
    sweep_pos = 160;
    ping();
    //distance = ping();
    Serial.println("Distance left = ");
    Serial.print(distance);
    Serial.print(" cm");
  }
}

void led_on() //Turn the LED on 
{
  Serial.println("");
  Serial.println("Led On");
  digitalWrite(Led, HIGH); 
}

void led_off() //Turn the LED off
{
  Serial.println("");
  Serial.println("Led Off");
  digitalWrite(Led, LOW);
}


unsigned long ping() //Read the HC-SR04 sensor
{
  //Trigger the sensor to send out a ping
 digitalWrite(trigPin, HIGH);
 delayMicroseconds(1000);
 digitalWrite(trigPin, LOW);
 duration = pulseIn(echoPin, HIGH);
 distance = (duration/2) /29.1;
 //Serial.print(distance);
 //Serial.println(" cm");
 //delay(500);
 //distance = ping();
}

void Forward() //This function tells the robot to go forward 
{
  Serial.println("");
  Serial.println("Moving forward");
  // turn on left motor   
  digitalWrite(in1, HIGH);   
  digitalWrite(in2, LOW);   
  // set speed out of possible range 0~255
  analogWrite(enA, 255);   
  // turn on right motor   
  digitalWrite(in3, LOW);   
  digitalWrite(in4, HIGH);   
  // set speed out of possible range 0~255   
  analogWrite(enB, 255);   
  //delay(100);
}

void Backward() //This function tells the robot to move backward
{
  Serial.println("");
  Serial.println("Moving backward");
  // turn on left motor   
  digitalWrite(in1, LOW);   
  digitalWrite(in2, HIGH);   
  // set speed out of possible range 0~255
  analogWrite(enA, 255);   
  // turn on right motor   
  digitalWrite(in3, HIGH);   
  digitalWrite(in4, LOW);   
  // set speed out of possible range 0~255   
  analogWrite(enB, 255);   
  //delay(100);
}

void Left() //This function tells the robot to turn left
{
  Serial.println("");
  Serial.println("Moving left");
  digitalWrite(in1, LOW);
  digitalWrite(in2, HIGH); 
// set speed out of possible range 0~255
  analogWrite(enA, 255); 
  digitalWrite(in3, LOW);
  digitalWrite(in4, HIGH);
// set speed out of possible range 0~255   
  analogWrite(enB, 255);   
  //delay(100);  
}

void Right() //This function tells the robot to turn right
{
  Serial.println("");
  Serial.println("Moving right");
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
// set speed out of possible range 0~255
  analogWrite(enA, 255); 
  digitalWrite(in3, HIGH); //Was High
  digitalWrite(in4, LOW);
  analogWrite(enB, 255);
  //delay(100);
}

void Stop() //This function tells the robot to stop moving
{
  Serial.println("");
  Serial.println("Stopping");
// now turn off motors   
  digitalWrite(in1, LOW);   
  digitalWrite(in2, LOW);
  //analogWrite(enA, 0);  
  digitalWrite(in3, LOW);   
  digitalWrite(in4, LOW);
  //analogWrite(enB, 0);
}

Posted: **Tue Sep 15, 2015 1:47 pm**

JonnyAlpha wrote:Hi;

Problems / Required Upgrades
What I need help with now is:
1. Forward and backwards works fine (could be a little more incremental) but I need to fine tune turning left and right, currently when clicking left or right the Robot spins almost 180 degrees, how do I adjust this (In Arduino Sketch).

Try setting the speed lower while the robot turns?

Code: Select all

void Right() //This function tells the robot to turn right
{
  Serial.println("");
  Serial.println("Moving right");
  digitalWrite(in1, HIGH);
  digitalWrite(in2, LOW);
// set speed out of possible range 0~255
  //analogWrite(enA, 255); reduce motor speed here
  analogWrite(enA, 125); 
  digitalWrite(in3, HIGH); //Was High
  digitalWrite(in4, LOW);
  //analogWrite(enB, 255); reduce motor speed here
  analogWrite(enB, 125);
  //delay(100);
}

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Fine Tune Raspberry Pi / Arduino Robot

Fine Tune Raspberry Pi / Arduino Robot

Re: Fine Tune Raspberry Pi / Arduino Robot