Let's Make Robots!

Antika - my little robot "a BoeBot-like robot"

a very basic obstacle detection/avoidance robot

hi,

this is my 1st robot, a very basic obstacle detection/avoidance robot.

 

 

 

 

 

 

 

 

 

 

 

UPDATE 12/06/2013:

- added IR control code. with the help of this excellent pdf file that explains IR and how to deal with it and also how to decode RCs: http://www.mediafire.com/download/jjmnaizseuk4dlq/Infrared_Remote_Control_Signal_Analysis_-_By_Karl_Williams.PDF

 

Background:

i started learning electronics two years ago, all i wanted to do is to be able to control things like a LED or so through the PC, so i spent sometime learning the basics of electricity and what components do i need to achieve my goal, i wrote down every thing i need (programmer, microcontroller, leds, resistors,.....etc),  and decided to code using basic language (having experience with pc programming languages like Delphi, VBA, C# made it a lot easier to learn), so got every thing and started to setup the circuit to just blink a LED, i remember that day very well, i spent the whole day trying not to blink a LED but to even switch it on, finally i was able to blink the LED i was sooo happy :D

then i learned how to send/receive data to/from a microcontroller through rs232, i programmed a little program using Delphi to monitor the serial port and been able finally to achieve my main goal, i was able to switch a LED on and off by a PC software :D.

the electronics field owned me i couldn't stop at this point, i started learning infrared and learned how to control every thing using a remote control, i stopped a while then decided to come back with a new project, a robot :D

 

The Robot project:

i started this project about a year ago, i wanted to make a basic obstacle detection/avoidance robot, spent sometime reading about sensors and servo motors basics, and finally decided to chose an ultrasonic sensor for my project, but as soon as i started, i started to face some problems

 

The problems:

1- the body of the robot: i managed to solve this using some plastic junk and hot glue (as you will see in the photos, but do not laugh :D)

2- the batteries: as i said before i started this project about one year ago, at that time, after preparing every thing (the circuit, the body, the code,...etc) i powered the robot to watch my final result, and i was shocked o_O, it was acting very strangely, because i was a beginner (and still), i used one 9 volts battery to power this robot, tried two with no luck, tried to separate the power supply of the servos but still no luck, so i got upset and delayed the whole thing untill two weeks ago i accidently came up with a topic in this site titled "selecting a proper battery for your robot" which made me realize how noob i am :D, so i decided to go back and finish what i started one year ago and got it working finally i am very happy with the final result :D

3- the servos was laggy, i discovered that removing the capacitors "that some people recommended using it for the servos" solved my problem, and the robot movement is very smooth now, not sure though when/why exactly do i have to attach those caps to the servos if it is working without them?!

 

Components:

- 1x PIC 16F628A microcontroller

- 1x ping ultrasonic sensor

- 1x standard servo motor for the sensor

- 2x continuous servo motors

- 3x 330 ohm resistors for the signal wire of the servos

- 1x breadboard

- 1x buzzer

- 2x LEDs "red + blue"

- 2x 330 ohm resistors for the LEDs

- 1x 20MHz crystal

- 2x 33 pF capacitors for the crystal

- 1x 9 volts battery for the microcontroller and the sensor

- 1x 7805 voltage regulator for the 9 volts battery

- 1x 10 uF + 1x 0.1 uF capacitors for the voltage regulator

- 4x 1.2 volt NiMH rechargeable AA batteries "2450 mAh" for the servos

- some wires

- hot glue + plastic junk for the body :D

- and most importantly a "good brain" :D

 

The code "ProtonBasic Compiler":

as you will see, i didn't "actually couldn't" use any timers or interrupts, i may implement them in the future, i managed to code without using them, i spent sometime to organise the code, and currently the robot works perfectly without them :D

'****************************************************************

'*  Name    : Antika Robot

'*  Author  : Khalid Fawzy

'*  Date    : 01-Jan-13

'*  Version : 1.0

'*  Notes   : This is my first attempt to make a robot, i hope

'*            that someone may find this code useful.

'****************************************************************

Device = 16F628A

Xtal = 20  

All_Digital = True 'To be able to use PORTA with IR Sensor

'-------[I/O Definitions]----------------------------------------------- 

Dim Ping As PORTB.3         'the ping sensor

Dim PingServo As PORTB.2    'servo motor for the ping sensor

Dim Servo1 As PORTB.0

Dim Servo2 As PORTB.1 

Dim StatusLed As PORTB.4

Dim RedLed As PORTB.5

Dim BeepPort As PORTB.6

Dim IR_Port As PORTA.0

Dim IRpulse_length[10] As Word

Dim IR_ON As Word

 

Dim hp As Word

Dim lp As Word

Dim xx As Byte

 

Dim Trigger  As Byte    '10 uS trigger pluse 

Dim Scale    As Byte    'raw x 2.00 =uS (2.00 if using 20MHz And 10.00 if 4MHz"

'RawToIn  var WORD      '1/73.746 (with**) 

Dim RawToCm  As Word    '1/29.034(with**) 

Trigger = 1 

Scale = 2 

'RawToIn = 889 

RawToCm = 2257 

 

Dim rawDist  As Word    'raw measurement 

'inches   var word 

Dim cm       As Word 

Dim i As Byte

Dim cmx As Byte

Dim CurrentPath As Byte

Dim BestPath As Byte

'-------[Program Code]--------------------------------------------------- 

DelayMS 100 'initialization

High StatusLed

High RedLed

DelayMS 300

Low StatusLed

Low RedLed

DelayMS 300

High StatusLed

High RedLed

DelayMS 300

Low StatusLed

Low RedLed

DelayMS 300

High StatusLed

High RedLed

DelayMS 300

Low StatusLed

Low RedLed

DelayMS 300

High StatusLed

 

cm = 0

cmx = 0

CurrentPath = 0

BestPath = 0

GoSub pingservo_90 'To Make The Ping Looks Forward

Low PORTB.7  'If Low: Disable IR and vise versa

RCIn PORTB.7,1,IR_ON

 

Start:

If IR_ON <> 0 Then

    GoTo IR_Control

Else

    GoTo Main

EndIf

 

 

'########################################################

'########################################################    

IR_Control:

PulsIn IR_Port,0,IRpulse_length[0]

If IRpulse_length[0] < 4000 Then

    GoTo Start

EndIf

 

 

For xx = 1 To 9 'skip first 10 pulses

    PulsIn IR_Port,1,IRpulse_length[0]

Next xx

 

For xx = 1 To 8 '8 command pulses

    PulsIn IR_Port,1,IRpulse_length[xx]

Next xx

 

PulsIn IR_Port,1,IRpulse_length[0] 'skip last pulse

';;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

 

CONVERT_BITS:

lp = 0

hp = 1    

For xx = 1 To 8

    If IRpulse_length[xx] > 500 Then

        lp = lp + hp    

    EndIf

    hp = hp*2

Next xx

 

LoopUntilNoIR: 'Repeat movement untill no IR

RCIn IR_Port,1,IRpulse_length[0]

Select IRpulse_length[0]

    Case <> 0

        If lp = 19 Then GoSub Left

        If lp = 20 Then GoSub Right

        If lp = 23 Then GoSub Forward

        If lp = 24 Then GoSub Backward

        If lp = 1 Then GoSub Right45

        If lp = 2 Then GoSub Right90

        If lp = 3 Then GoSub Left45

        If lp = 4 Then GoSub Left90

        GoTo LoopUntilNoIR

    Case = 0

        GoSub StopServos

EndSelect

 

GoTo Start

'#########################################################

'#########################################################

 

Main:

    GoSub Forward_Scan

GoTo Main

Detection:   

    Low PingServo 'i should stop the ping servo here, but i do not know the right pulse to stop this servo

    GoSub StopServos 

    High BeepPort

    DelayMS 50

    Low BeepPort

    DelayMS 50

    High BeepPort

    DelayMS 50

    Low BeepPort 

    DelayMS 50

    High BeepPort

    DelayMS 50

    Low BeepPort 

    GoSub BackwardX

    GoSub pingservo_90  'positioning the ping servo in Forward Position to start scanning

    DelayMS 5

    GoSub pingservo_0   'scanning most right for obstacles

    DelayMS 5

    GoSub pingservo_45  'scanning 45 degrees to the right for obstacles

    DelayMS 5

    GoSub pingservo_135 'scanning 45 degrees To the left for obstacles

    DelayMS 5

    GoSub pingservo_180 'scanning most left for obstacles

    DelayMS 5

 

    Select BestPath

    Case 1 '0 

        GoSub Right90

    Case 2 '45 

       GoSub Right45

    Case 3 '135 

        GoSub Left45

    Case 4' 180 

        GoSub Left90

    EndSelect

 

    cm = 0

    cmx = 0

    CurrentPath = 0

    BestPath = 0

    GoSub pingservo_90 

GoTo Start

 

'------[Subroutines]----------------------------------------------------- 

'note that: i tuned the number of loops and delays to suit my needs

Get_Sonar: 

    Low Ping                            'make trigger 0-1-0 

    PulsOut  Ping, Trigger              'activate sensor 

    PulsIn  Ping, 1, rawDist            'measure echo pulse 

    rawDist = rawDist * Scale           'convert to uS 

    rawDist = rawDist / 2               'remover return trip 

    'inches = rawDist ** RawToIn        'convert to inches 

    cm = rawDist ** RawToCm             'convert to sentimeters

Return 

 

pingservo_0: 'turn to most right

    CurrentPath = 1

    For i = 1 To 24 '24 long enough to reach destination "425"

    Low PingServo

    Servo PingServo, 425 '425 = farthest right...got it with trial & error :D

    DelayMS 15 'the delay controls servo speed

    Next i 

    GoSub Get_Sonar

    If cm > cmx Then

    cmx = cm

    BestPath = CurrentPath

    EndIf 

Return

 

pingservo_45: 'turn 45 degrees to right

    CurrentPath = 2

    For i = 1 To 18

    Low PingServo

    Servo PingServo, 850

    DelayMS 15

    Next i

    GoSub Get_Sonar

    If cm > cmx Then

    cmx = cm

    BestPath = CurrentPath

    EndIf 

Return

 

pingservo_90: 'turn to center position

    For i = 1 To 24

    Low PingServo

    Servo PingServo, 1275

    DelayMS 15

    Next i

Return

 

pingservo_135: 'turn 45 degrees to left

    CurrentPath = 3

    For i = 1 To 24

    Low PingServo

    Servo PingServo, 1700

    DelayMS 15

    Next i

    GoSub Get_Sonar

    If cm > cmx Then

    cmx = cm

    BestPath = CurrentPath

    EndIf 

Return

 

pingservo_180: 'turn to most left

    CurrentPath = 4

    For i = 1 To 18

    Low PingServo

    Servo PingServo, 2125

    DelayMS 15

    Next i

    GoSub Get_Sonar

    If cm > cmx Then

    cmx = cm

    BestPath = CurrentPath

    EndIf 

Return

 

'moving forward and scanning for obstacles at the same time

Forward_Scan:

    For i = 1 To 10

    Low PingServo

    Low Servo1

    Low Servo2

    Servo PingServo, 850

    Servo Servo1, 1000 ' Send a 1 ms pulse

    Servo Servo2, 2000 ' Send a 2 ms pulse

    DelayMS 17

    Next i

    GoSub Get_Sonar

    If cm <= 18 Then

    GoSub Turn_Right

    EndIf

 

    For i = 1 To 10

    Low PingServo

    Low Servo1

    Low Servo2

    Servo PingServo, 1275

    Servo Servo1, 1000

    Servo Servo2, 2000

    DelayMS 15

    Next i

    GoSub Get_Sonar

    If cm <= 20 Then

    GoTo Detection

    EndIf

 

    For i = 1 To 10

    Low PingServo

    Low Servo1

    Low Servo2

    Servo PingServo, 1700

    Servo Servo1, 1000

    Servo Servo2, 2000

    DelayMS 17

    Next i

    GoSub Get_Sonar

    If cm <= 18 Then

    GoSub Turn_Left

    EndIf

 

    For i = 1 To 10

    Low PingServo

    Low Servo1

    Low Servo2

    Servo PingServo, 1275

    Servo Servo1, 1000

    Servo Servo2, 2000

    DelayMS 15

    Next i

    GoSub Get_Sonar

    If cm <= 20 Then

    GoTo Detection

    EndIf

Return

 

Turn_Right: 'turn right until no obstacle detected

    High RedLed

    Low Servo1

    Low Servo2

    Servo Servo1, 1000

    Servo Servo2, 1000

    DelayMS 20

    GoSub Get_Sonar

    DelayMS 10

    If cm <= 18 Then

    GoTo Turn_Right

    EndIf

    GoSub StopServos

    Low RedLed

Return 

 

Turn_Left: 'turn left until no obstacle detected

    High RedLed

    Low Servo1

    Low Servo2

    Servo Servo1, 2000

    Servo Servo2, 2000

    DelayMS 20

    GoSub Get_Sonar

    DelayMS 10

    If cm <= 18 Then

    GoTo Turn_Left

    EndIf

    GoSub StopServos

    Low RedLed

Return       

 

StopServos:

    Low Servo1

    Low Servo2

    Servo Servo1, 1500 ' 1.5 ms

    Servo Servo2, 1500 ' 1.5 ms

    DelayMS 20

Return

 

BackwardX: 'move backward when detecting obstacles

    High RedLed

    For i = 1 To 10

    Low Servo1

    Low Servo2

    Servo Servo1, 2000 ' Send a 2 ms pulse 'Servo command is independent in OSC speed, always 1us

    Servo Servo2, 1000 ' Send a 1 ms pulse

    DelayMS 30

    Next i

    GoSub StopServos

    Low RedLed

Return

 

Left45: 'turn the robot To 45 degrees to left

    High RedLed

    For i = 1 To 9

    Low Servo1

    Low Servo2

    Servo Servo1, 1000

    Servo Servo2, 1000

    DelayMS 20

    Next i

    GoSub StopServos

    Low RedLed

Return      

 

Left90: 'turn the robot To most left

    High RedLed

    For i = 1 To 20

    Low Servo1

    Low Servo2

    Servo Servo1, 1000

    Servo Servo2, 1000

    DelayMS 20

    Next i

    GoSub StopServos

    Low RedLed

Return      

 

Right45: 'turn the robot To 45 degrees to right

    High RedLed

    For i = 1 To 9

    Low Servo1

    Low Servo2

    Servo Servo1, 2000

    Servo Servo2, 2000

    DelayMS 20

    Next i

    GoSub StopServos

    Low RedLed

Return  

 

Right90: 'turn the robot to most right

    High RedLed

    For i = 1 To 20

    Low Servo1

    Low Servo2

    Servo Servo1, 2000

    Servo Servo2, 2000

    DelayMS 20

    Next i

    GoSub StopServos

    Low RedLed

Return 

 

Final notes:

- this is my 1st attempt, i know the body should be better, i may upgrade it in the future.

- i used the QL-2006 programmer and ProtonBasic compiler to program the microcontroller, my total code is 1138 words from a possible 2048 words for this PIC chip "55.57%".

- electronics & programming are my hobby, i do not work in those fields :)

 

and now the comedy show :D

 

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

Well done and welcome to LMR. 

NOBODY is laughing about the body, we have seen more strange things here :-) Important is that your idea is working, not how professional it looks. Seeing bodies like this makes people think that they not need to buy expensive things to build a robot...and this is the message here on LMR, make things within your limits. I started with some DVD platfor robot too...and my Mouse robot also did not win the price of beauty :-)

i appreciate your kind words, there is another message i would like to add: you can do whatever you want as long as you have a strong will, entering electronics field is really easy, you just need to learn the basics and to be patient, thats all :D

BTW i work as an accountant, and this alone is another message :D

I like your wheels and caster.

Thank you for sharing. I'm new to LMR and like the reuse of materials.

i am very glad that you liked it :)

That obstacle avoidance works really nice! I have to try that scanning and small adjustment thingie sometime too. Thanks for the good pictures and good write-up, it's really nice to see what kind of things people build from basic and recycled materials!

as my first bot, i never thought that people will like it :D, thanks for the encouragement.

ana 3rft ank 3rby mn al korsy wallahy shaklak masry kaman :D

3agbny f3ln al robot bta3ak w gamil gdn msa 3leh w ana sha8al 3la robot bardo bas mtlt3 feh

yaret lw mn masr ole gbt al servohat mnen w bkam w 7lw gdn w rbna m3ak isa :)

w 3ndy so2al

anta msh8l al sensor azay 3la 628a?

bel comprator b2a wla a?

 

Please read the Rules. There you can see "Write the best English you can. Avoid "txt spk" or "1ee7 5p3ak"."

We are not very picky but to keept that website a reliable source for all other DIY roboteers out there we need to keep the content clean. Nobody can find something if you write LEET as nobody will search for R0807 in Google.

...