Line tracer robot

[cibotsan]

Dear all especially Steve.
I had design a line tracer robot for my college. My knowledge about micro controller is very basic that why a needs your help.
for you info.
pic 16F877A
' input
portb.1 = Left Sensor (LS)
portb.2 = Center Sensor (CS)
portb.3 = Right Sensor (RS)

iam using 3 photo sensor.

' Output
portb.4 = Left Motor FWD. (LM_FWD)
portb.5 = Left Motor REV. (LM_REV)
portb.6 = Right Motor FWD. (RM_FWD)
portb.7 = Right Motor REV. (RM_REV)

iam using "H" bridge to driving my 2 DC motor.
What i want to know is,
1. How to control the robot, like this operation

LS(0) CS(1) RS (0) LM_FWD(FULL SPEED) RM_FWD (FULL)
LS(1) CS(1) RS (0) LM_FWD(HALF SPEED) RM_FWD (FULL)
LS(1) CS(1) RS (0) LM_FWD(MIN SPEED) RM_FWD (MAX)
LS(0) CS(1) RS (1) LM_FWD(HALF) RM_FWD (MAX)
LS(0) CS(0) RS (1) LM_FWD(MAX SPEED) RM_FWD (MIN)

2. another things is how to control
if the 3 Sensor = 1 3 times cross 4 junction, the robot will stop and turn 90 deg left (for example)

which is easier using PWM or Pulseout?
Please guy help me.

[mister_e]

By what you provide, it will look like almost this

TRISB=%00001111


LM_FWD         var     PORTB.4
LM_REV         var     PORTB.5
RM_FWD         var     PORTB.6
RM_REV         var     PORTB.7

MaskPORTB      var     byte
PeriodHALF     var     word ' Variable for Half Speed period (pulsout)
PeriodMIN      var     word ' Variable for Min Speed period (pulsout)

' You'll have to determine value for PeriodMIN & PeriodHALF here

PORTB=0

Start:
      MaskPORTB=(PORTB>>1) & $07 ' get only B1,B2,B3 value
      Select case maskportb
             
             'LS(0) CS(1) RS (0) LM_FWD(FULL SPEED) RM_FWD (FULL)
             case 2 
                  LM_FWD =1
                  RM_FWD =1
                  
             'LS(1) CS(1) RS (0) LM_FWD(HALF SPEED) RM_FWD (FULL)
             case 3
                  pulsout LM_FWD, PeriodHALF
                  RM_FWD=1

             'LS(0) CS(1) RS (1) LM_FWD(HALF) RM_FWD (MAX)
             case 6
                  pulsout LM_FWD, PeriodHALF
                  RM_FWD=1

             'LS(0) CS(0) RS (1) LM_FWD(MAX SPEED) RM_FWD (MIN)
             case 4
                  LM_FWD = 1
                  pulsout RM_FWD,PeriodMIN
      end select
      goto start

be sure of the way you interpret your sensor... i'm not sure about the info you provide.

2. another things is how to control
if the 3 Sensor = 1 3 times cross 4 junction, the robot will stop and turn 90 deg left (for example)

you mean ?

[cibotsan]

Thanks again steve for your solution.

quote:
--------------------------------------------------------------------------------
2. another things is how to control
if the 3 Sensor = 1 3 times cross 4 junction, the robot will stop and turn 90 deg left (for example)

--------------------------------------------------------------------------------

what i trying to do is ( reffer to attached file) the robot move follow the line and after cross the 3rd junction the robot will stop and after few second robot will turn CCW and stop again when the line sensor is detected the 90 deg line.
sorry for my bad english ,

[mister_e]

sorry for my bad english

that's familiar to me... i'm french.

BTW, your picture helps a lot to figure out what you want to do.

Have a counter variable, and check for your three sensor signal comming...

MyCounter     VAR     BYTE
MyCounter=0


' Add this line to the SELECT CASE stuff
          CASE 7 'when all 3 sensor tripped
               IF MyCounter<3 then
                   MyCounter = MyCounter + 1
               ELSE
                   Gosub LetsTurn90Degree
               ENDIF

[cibotsan]

You always not dissapointed me steve,what a generous person you are .Right now iam out station, so after comming back, i will try it and give the result, thanks again steve
regards
fanzi

[cibotsan]

dear Steve,
I try already, and it was sucessfull. Many thanks to you Steve. i learned how to make linetracer robot from you.
regards
fauzi

[mister_e]

Great to know that guy!

Good luck!