Need Some Assistance

Londonguy

Hey all, any help with my program would be greatly appreciated, as i am a beginner with this stuff.

anyways for a college project i am required to build a robot that can follow a track, as well as avoid objects on this track.

What i have used is two IR emitters/recievers and two line tracker sensors.· I was succesfully able to hook up these sensors, and have them read either 0 or 1 depending on the condition.· However when i wrote the movement programming the robot seems to be slow and confused, and does not do as it is required.·· I have thought of programming the robot to re check the sensors after each condition is met, (ie robot moves to avoid sensor) but still the robot.· Does anyone have an sample coding regarding this type of robot?··· also im curious if there is any way to save the last movement, so that if the robot has to move off the track to avoid object(s) thus making the line tracker sensors both "read off the track", then the microprocessor will remember the last movement and be able to return to the track..· Thanks for any help

LoopyByteloose

First of all, if the processor has too many sensor tasks; it will slow the response. A balance must be achieved or a co-processor must offload some of the burden.

Second, some IR sensors are power hungry and using an array of such will starve the BOT.

Third, whiskers or bumpers are always a good idea as IR responds differently to different colors and may actually miss some of what you hope for it to see.

Having said that, it is obvious that we could use more specific information.

What IR sensors are you using?
Where are you getting your code for them?

It may be to your advantage to post the program here.
Experienced people can then tell you what might improve upon it.

Cheers.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"When all think alike, no one is thinking very much.' - Walter Lippmann (1889-1974)

······································································ Warm regards,····· G. Herzog [noparse][[/noparse]·黃鶴 ]·in Taiwan

Ken Gracey

Londonguy,

You can do this all with a BASIC Stamp, without a coprocessor. I suggest you first develop your pseudocode in plain ol' English. For example:

Generate IR and look for reflection
Steer the robot towards the line
Check for obstruction in front of the robot
If obstruction is encountered, back up, turn
If no line, drive until line is seen
Once line is found, center it under sensors

I think a CASE..SELECT statement could manage most all of your project.

The problem you are having is likely one of timing. You indicate that the robot is slow; are there DEBUG statements in the code? Are you trying to do everything state-machine style between servo pulses?

Ken Gracey

Londonguy

This is what i have done, its a garbled mess of code that ive scavenged from other parallax projects and programming guide..· as you can see im a beginner lol.· this code is pretty rough, and its probably why im having such a problem gettin the results i want.· Im sure the problem is in the movement code since my sensors seem to be working properly

'

---

[noparse][[/noparse] I/O Definitions ]

---

LLinePwr PIN 9 ' left line sensor power
LLineIn PIN 8 ' left line sensor input
RLinePwr PIN 7 ' right line sensor power
RLineIn PIN 6 ' right line sensor input


'

---

Variables

---

counter·········· VAR···· Word
sub_count········ VAR···· Byte
irdetectleft····· VAR···· Bit
irdetectright···· VAR···· Bit
lLine VAR Word ' left sensor raw reading
rLine VAR Word ' right sensor raw reading
lineBits VAR Nib ' decoded sensors value
lbLeft VAR lineBits.BIT1
lbRight VAR lineBits.BIT0
'

---

Movement Code

---

FREQOUT 4, 2000, 3000 ' Signal program start/reset.


DO
·GOSUB Readirsensors·· '0 clear 1 object
IF (irDetectLeft = 1) AND (irDetectRight = 1) THEN···· ' Both IR pairs detect obstacle
· GOSUB rev_pulse
· GOSUB turn_left·································· ' Back up & turn left
···································· ' go forward and turn right to
··································· 'back on track.
ELSEIF (irDetectLeft = 1) THEN····················· ' Left IR pair detects
· GOSUB rev_pulse···································· ' Back up & turn right
· GOSUB turn_right

ELSEIF (irDetectRight = 1)· THEN····················· ' Right IR pair detects
· GOSUB rev_pulse····································· ' Back up & turn left
· GOSUB turn_left

ELSE·················································· ' Both IR pairs 1, no detects
· GOSUB fwd_pulse····································· ' Apply a forward pulse

ENDIF················································· ' and check again


GOSUB Readlinesensors······· ' 0 = black, 1 = line
IF (lbLeft = 1) AND (lbRight = 1) THEN
· GOSUB turn_right
· GOSUB fwd_pulse
ELSEIF (lbLeft = 1) THEN
· GOSUB turn_right
ELSEIF (lbRight = 1) THEN
· GOSUB turn_left
ELSE
· GOSUB fwd_pulse
ENDIF

LOOP
'

---

sensor subroutines

---

·Readlinesensors:
HIGH LLinePwr ' activate sensors
HIGH RLinePwr
HIGH LLineIn ' discharge caps
HIGH RLineIn
PAUSE 1
RCTIME LLineIn, 1, lLine ' read left sensor
RCTIME RLineIn, 1, rLine ' read right sensor
LOW LLinePwr ' deactivate sensors
LOW RLinePwr
' convert readings to bits
LOOKDOWN lLine, >=[noparse][[/noparse]1000, 0], lbLeft ' 0 = black, 1 = line
LOOKDOWN rLine, >=[noparse][[/noparse]1000, 0], lbRight
DEBUG CR, "lbleft = ", BIN1 lbleft
DEBUG CR, "lbRight =", BIN1 lbRight
RETURN

ReadIrsensors:
FREQOUT 10, 1, 38500
irDetectLeft = IN11
DEBUG HOME, "irDetectLeft = ", BIN1 irDetectLeft
PAUSE 50
FREQOUT 12, 1, 38500
irDetectRight = IN13··
DEBUG CR, "irDetectRight = ", BIN1 irDetectRight
PAUSE 50
RETURN
·'

---

Navigation Subroutines

---

fwd_pulse:······ ' forward subroutine
· FOR counter = 1 TO 50
· PULSOUT 1, 950
· PULSOUT 2, 550
· PAUSE 20
· NEXT
RETURN
rev_pulse:······ ' reverse subroutine
· FOR counter = 1 TO 50
· PULSOUT 1, 550
· PULSOUT 2, 950
· PAUSE 20
· NEXT
RETURN
turn_right:······ '45 degree Right turn Subroutine
· FOR counter = 1 TO 45··
PULSOUT 1, 800
·· PAUSE 20
· NEXT
RETURN
turn_left:······· '45 degree left turn subroutine
FOR counter = 1 TO 45
· PULSOUT 2, 700
· PAUSE 20
· NEXT
RETURN