ahh glad its not just me,

Just thought I could show you on Skype what your project does with my bot.

Email?

rich@richpyke.net

I forgot to mention that v1.1.1 is on the cloud.

A couple of changes so far (although still working on it when I find the time);

1. Modified code so it doesn't reverse after escaping from boxing in or avoiding a left/right/left/right loop.
2. Added in a stop and a sleep before all forward and reverse movements.
3. Added an emergency stop script which stops the roam script and stops any movement that's currently happening.

I just ran it again to check it out and had no errors this time. I suspect it may have been down to the computer running slowly when I last tried it, but also sounds like low battery levels and inaccurate ping readings may also cause strange behaviour. I'm thinking of ways around that, something like taking 3 readings each time rather than 1, and using ands in the ifs to only be true if all 3 readings are below the threshold... but I've not had chance to do that yet.

The inspiration needed to complete version 1.1.2 of the Ping Roam script came tonight.

Changes

1. Changed escape return to use else therefore avoiding reversing and turning after an escape.
2. Added in stop and sleep before any forward or reverse movements.
3. Added emergency stop script.
4. All ports are now constants, use ports specified in the head of the code or port summary or adjust the code to suit your ports.

Plenty of comments so you can follow and customise the script where necessary.

# Ping Object Avoidance
# Using Ultra Sonic Ping Sensor on servo for avoidance
# Version 1.1.2


# Configuration Settings
# This script assumes the following ports;
#
# Trig Port = D0
# Echo Port = D1
# Sweep servo = D2

# Adjust values below for movement control
$reverseturn = 1 # Reverse before turn? 0 = no, 1 = yes
$maxdistance = 30 # Change for maximum distance from object before avoiding in units
$boxedindistance = 20 # Change for maximum distance for boxed in detection
$turnamount = 500 # Change for how long to turn for in ms
$reverseamount = 500 # Change for how long to reverse for in ms (if applicable)
$movementspeed = 255 # Change for movement speed
$slowturn = 127 # Change for slow turn speed

# Adjust values below for sweep configuration
$sweepmin = 10 # Change for min limit
$sweepmax = 90 # Change for max limit
$sweepservodelay = 500 # Change for delay between sweep servo movements and readings

# Testing Options
$testmode = 0 # Change to 1 if testing without PING sensor



# Do not adjust these values
# Calculate the centre position for the sweeping servo
# Minimum position plus maximum position divided by 2
# Round to 0 decimal places
$sweepcenter = Round((($sweepmin+$sweepmax)/2),0)
# Set the previous position to the max position for initial movement
$sweepprevious = $sweepmax # Do not change
# Set the current position to the centre position for initial movement
$sweepcurrent = $sweepcenter # Do not change
# Set some flags for testing - to be removed in final release
$SweepErrorFlag = 0 # Do not change
$BoxedInErrorFlag = 0 # Do not change
$BoxedInRun = 0 # Do not change
$SweepCenterRun = 0 # Do not change
$EscapeRun = 0 # Do not change
$ScriptErrorFlag = 0 # Do not change
$isboxedin = 0 # Do not change
# Set last and penultimate moves.
$penultimatemove = "none"
$lastmove = "none"



# ------- The Script --------

# Set the start point for any loops
:begin

# Center the sweep servo
Servo(D2, $sweepcenter)

# Start moving forwards
FORWARD()

# Start the detection
Goto(detect) # This line is redundant but left for educational purposes



# Detection code

# Set a label for loops and gotos
:detect

# Use random numbers if in test mode - to be removed in final release
IF ($testmode=0)
  $currentdistance = GetPing(D0, D1)
ELSE 
  $currentdistance = GetRandom(0,255)
ENDIF 
  
  # Check the current distance against the max allowed distance
IF ($currentdistance <= $maxdistance)
  # If the current distance is below the max distance start avoiding
  GOTO(avoid)
  
  # Set label for avoid return to avoid return errors
  :avoidreturn
ENDIF 
  
# Run the sweeping servo code
GOTO(sweep)

# Wait
SLEEP ($sweepservodelay)

# Loop back to the start of detection
GOTO(detect)



# Avoidance code

# Set a label for loops and gotos
:avoid

# First check if boxed in
Goto(boxedin)

# If the robot is boxed in run the escape code
IF ($isboxedin = 1)
  Goto(escape)
  
  # Avoid return error after escape loop by setting a label for a goto
  :escapereturn
  
# Change to else to avoid reversing and turning after an escape - dont forget the endif at the bottom
ELSE 
  
  # Check to see if to reverse before turning
  IF ($reverseturn = 1)
    # If the option of reverse before turning is set stop then reverse
    # Add in a stop and sleep before movement
    Stop()
    Sleep(200)
    Reverse($movementspeed,$reverseamount)
  ENDIF 
    
  # Check the servo position
    
  # Check if it's to the left
  IF ($sweepcurrent = $sweepmin)
    # If the servo is in the lowst position (left) move right
    Goto(moveright)
    # Continue moving forwards
    # Add in a stop and sleep before movement
    Stop()
    Sleep(200)
    FORWARD()
    
  # Else check if it's to the right
  ELSEIF ($sweepcurrent = $sweepmax)
    # If the servo is in the highest position (right) move left
    Goto(moveleft)
    # Continue moving forwards
    # Add in a stop and sleep before movement
    Stop()
    Sleep(200)
    FORWARD()
    
  # Else assume it's in the middle
  ELSE 
    # If the servo is in the center position check which side is closest to the object and move the other way
    
    # Move and check the left side
    Servo(D2,$sweepmin)
    # Use random numbers if in test mode
    IF ($testmode=0)
      $pingmin = GetPing(D0, D1)
    ELSE 
      $pingmin = GetRandom(0,255)
    ENDIF 
      
    # Wait
    Sleep(400)
    
    # Move and check the right side
    Servo(D2,$sweepmax)
    # Use random numbers if in test mode
    IF ($testmode=0)
      $pingmax = GetPing(D0, D1)
    ELSE 
      $pingmax = GetRandom(0,255)
    ENDIF 
      
    # Wait
    Sleep(400)
    
    # Move and check the center
    Servo(D2,$sweepcenter)
    IF ($pingmin > $pingmax)
      Goto(moveright)
      # Add in a stop and sleep before movement
      Stop()
      Sleep(200)
      FORWARD()
    ELSE 
      Goto(moveleft)
      # Add in a stop and sleep before movement
      Stop()
      Sleep(200)
      FORWARD()
    ENDIF 
  ENDIF 
ENDIF 
  
# Return to the main code
Goto(avoidreturn)



# The sweep code

# Set a label for loops and gotos
:sweep

# Move in the correct direction and store previous position

# Check what the current position is
# Check if left
IF ($sweepcurrent = $sweepmin)
  
  # Save the current position as the previous
  $sweepprevious = $sweepcurrent
  
  # Move to the next position
  Servo(D2, $sweepcenter)
  
  # Save the current position
  $sweepcurrent = GetServo(D2)
  
# Else check if its center and where it was before
# If it is center and was left before
ELSEIF ($sweepcurrent = $sweepcenter and $sweepprevious = $sweepmin)
  
  # Save the current position as the previous
  $sweepprevious = $sweepcurrent
  
  # Move to the next position
  Servo(D2, $sweepmax)
  
  # Save the current position
  $sweepcurrent = GetServo(D2)
  
# If it is center and was right before
ELSEIF ($sweepcurrent = $sweepcenter and $sweepprevious = $sweepmax)
  
  # Save the current position as the previous
  $sweepprevious = $sweepcurrent
  
  # Move to the next position
  Servo(D2, $sweepmin)
  
  # Save the current position
  $sweepcurrent = GetServo(D2)
  
# Else check if right
ELSEIF ($sweepcurrent = $sweepmax)
  
  # Save the current position as the previous
  $sweepprevious = $sweepcurrent
  
  # Move to the next position
  Servo(D2, $sweepcenter)
  
  # Save the current position
  $sweepcurrent = GetServo(D2)
  
# Else something has gone wrong
ELSE 
  # Set an error flag for debugging purposes - to be removed for final release
  $SweepErrorFlag = 1
ENDIF 
  
# Return back to the main script
Return()



# The sweep center code

# Set a label for loops and gotos
:sweepcenter

# Set a flag so we know it has run for debugging purposes
$SweepCenterRun = 1

# Move the servo to the left position
Servo(D2,$sweepmin)

# Use random numbers if in test mode
IF ($testmode=0)
  $pingmin = GetPing(D0, D1)
ELSE 
  $pingmin = GetRandom(0,255)
ENDIF 
  
# Wait
Sleep(200)

# Move the servo to the right
Servo(D2,$sweepmax)

# Use random numbers if in test mode
IF ($testmode=0)
  $pingmax = GetPing(D0, D1)
ELSE 
  $pingmax = GetRandom(0,255)
ENDIF 
  
# Wait
Sleep(200)

# Move the servo back to the center
Servo(D2,$sweepcenter)

# Check which side has the closest object
# If the object to the left is further away than the object to the right
IF ($pingmin > $pingmax)
  
  # Move to the right
  RIGHT($movementspeed,$turnamount)
  
  # Move forwards again
  # Add in a stop and sleep before movement
  Stop()
  Sleep(200)
  FORWARD()
  
# Else if the object to the right is further away than the object to the left
ELSEIF ($pingmin < $pingmax)
  
  # Move to the left
  LEFT($movementspeed,$turnamount)
  
  # Move forwards again
  # Add in a stop and sleep before movement
  Stop()
  Sleep(200)
  FORWARD()
  
# Else they are both the same
ELSE 
  
  # So move left - this can be customised
  LEFT($movementspeed,$turnamount)
  
  # And move forwards again
  # Add in a stop and sleep before movement
  Stop()
  Sleep(200)
  FORWARD()
ENDIF 
  
# Return to the main code
Return()



# The boxed in code

# Set a label for loops and gotos
:boxedin

# Set a flag so we know it has run for debugging - to be removed for final release
$BoxedInRun = 1

# Get distance to the side
# Move the servo to the left
Servo(D2,$sweepmin)

# Use random numbers if in test mode - to be removed for final release
IF ($testmode=0)
  $side1scan = GetPing(D0, D1)
ELSE 
  $side1scan = GetRandom(0,255)
ENDIF 
  
# Get distance to the other side
# Move the servo to the right
Servo(D2,$sweepmax)

# Use random numbers if in test mode
IF ($testmode=0)
  $side2scan = GetPing(D0, D1)
ELSE 
  $side2scan = GetRandom(0,255)
ENDIF 
  
# Get distance to the front
# Move the servo to the center
Servo(D2,$sweepcenter)

# Use random numbers if in test mode
IF ($testmode=0)
  $centerscan = GetPing(D0, D1)
ELSE 
  $centerscan = GetRandom(0,255)
ENDIF 
  
# Check if boxed in by compairing the results against a fixed boxed in distance
IF ($side1scan < $boxedindistance and $side2scan < $boxedindistance and $centerscan < $boxedindistance)
  
  # If any are true set the boxed in flag
  $isboxedin = 1
  
ENDIF 
  
# Return to the main script
Return()



# The escape code

# Set a label for loops and gotos
:escape

# Set a flag so we know it has run for debugging
$EscapeRun = 1

# Reset the boxed in flag
$isboxedin = 0

# Center the sweep servo
Servo(D2,$sweepcenter)

# Turn slowly
Left($slowturn)

# Set up a loop
:escapeloop

# Scan until clear
# Use random numbers if in test mode
IF ($testmode=0)
  $escapescan = GetPing(D0, D1)
ELSE 
  $escapescan = GetRandom(0,255)
ENDIF 
  
# If the scan result is below the boxed in distance loop
IF ($escapescan < $BoxedInDistance)
  
  # Go back to the start of the escape loop
  Goto(escapeloop)
  
ENDIF 
  
# Continue forwards
# Add in a stop and sleep before movement
Stop()
Sleep(200)
FORWARD()

# Return to the main script
Goto(escapereturn)



# Move Right code

# Set a label for loops and gotos
:moveright

# Check the last 2 moves to avoid left right left right loops
IF ($lastmove = "left" and $penultimatemove = "right")
  
  # If it has been right then left dont move right again but escape from a loop
  Goto(escape)
  
  # Reset the last move
  $lastmove = "none"
  
  # Else just move right
ELSE 
  RIGHT($movementspeed,$turnamount)
  Sleep(200)
  
  # Save the penultimate move
  $penultimatemove = $lastmove
  
  # Save the last move
  $lastmove = "right"
  
ENDIF 
  
# Go back to the main script
Return()



# Move left code

# Set a label for loops and gotos
:moveleft

# Check the last 2 moves to avoid left right left right loops
IF ($lastmove = "right" and $penultimatemove = "left")
  
  # If it has been left then right dont move left afain but escape from a loop
  Goto(escape)
  
  # Reset the last move
  $lastmove = "none"
  
  # Else just move left
ELSE 
  LEFT($movementspeed,$turnamount)
  Sleep(200)
  
  # Save the penultimate move
  $penultimatemove = $lastmove
  
  # Save the last move
  $lastmove= "left"
  
ENDIF 
  
# Go back to the main script
Return()

# End of scripts

This script has not been real world tested - Testbot has been re-purposed to become Jarvis. As a result I am currently unable to run any real world tests on the code. I will be temporarily adding the sweeping servo and ping sensor to Jarvis as soon as I possibly can however in the mean time any comments on it's success or failure would be very much appreciated.

The project is on the EZ-Cloud under Public Library, Examples, Ping Roam V1.1.2 or you can Download here

Also available for copy and paste on pastebin here

Any improvements are welcomed also. For instance, one question I often think about when I am writing this script is Would it be better written to use 3 Ping Sensors rather than a sweeping servo? What is more commonly used, Ping or IR? What do the people want it to do?

So hit it up with suggestions, requests, whatever I have no problem writing a bunch of these for the different methods either, I'm not afraid of a little coding!..

Rich,

Can you send us a video? I would love to see how it behaves.

Very elaborate and well commented code!

Bill

I will do when I have a robot that is capable of running the code (Jarvis is being temporarily repurposed but the adaptation is taking a little longer than I planned).

@Rich, I'd like to try this using a modified Roomba with the Ping sensor centrally located at the front of the body. Using the two H-bridges built into the Roomba PCB. Each H-bridge has a forward and reverse PWM lead. What EZ-B control would best suit this trial ?