Help!! Ping maze Navigation.

kolai

I saw this video on youtube, and I'm impressed on how the bot solved the maze (on the last part with red walls) using the "Ping ultrasonic Sensor". Any Ideas on the bots algorithm and how the code works?.

I'm planning to join a Walled maze solving competition and I'm planning to use the "Ping sensor" or with both IR detectors and Ping))). I'm sure ping will be enough for the maze.

Thanks for all your help.

the youtube link:

doggiedoc

It appears from the video that the algorithm is more of a "left turn wall following" routine. I didn't see any real maze solving logic there. Looked like great use of the Ping))) mounting bracket kit - notice the left to center scanning action of the sensor?

Paul

kolai

thanks paul,it likes a " left hand rule " right?. Another Question does the ping sensor output Binary numbers (PingDetectLeft = 0 'object detected @ left' and PingDetectCenter = 0 'Object dtected @ center').? Or in does it output only distance in decimal?(if decimal, you would compare the two cm by cm). If so, any ideas on the algorithm? and have any ideas on how to scan and compare to directions.?

thanks. very much appreciated

doggiedoc

There are some excellent examples and details on the PING)))'s product page under "Resources an Downloads".

doggiedoc

I found a plethora of information on maze solving algorithms here.

Hope that helps you.

Paul

kolai

Thanks so much paul. The algorithm looks easy if your going to apply it to the " IR Detectors "
But for a "PING" its hard (for me as a mediate programmer) I tried to understand some of the examples on the "PING product page" and I stumbled on one source. And its "RoamingwithPing", to apply the Rule showed on the video, should I delete the parts where in a "Right Sweep" place?. Can you also show me how it is done on coding, through editing the "RoamingwithPing"? The "RoamingWithPing" gives me a headache as the codes is really hard to understand.

Thanks

kolai

For quite some time, at last i figured it out!!!

Since i only want to use the ping sensor as a front sensor, i didnt mount it with the servo.
Here's the code, its 2 ir Sensors with ping as the front sensor.

' {$STAMP BS2}
' {$PBASIC 2.5}

time VAR Word
cm VAR Word
in VAR Word
ft VAR Word
cmcons CON 2260
incons CON 890
ftcons CON 74

counter VAR Byte
irDetectLeft VAR Bit
irDetectRight VAR Bit

DO

PULSOUT 15, 5
PULSIN 15, 1, time


cm = cmcons ** time
in = incons ** time
ft = ftcons ** time

FREQOUT 9, 1, 38500 ' Check IR Detectors
irDetectLeft = IN10

FREQOUT 8, 1, 38500
irDetectRight = IN0


DEBUG HOME, "time = ", DEC5 time
DEBUG CR, "cm = ", DEC3 cm, "cm"
DEBUG CR, "in = ", DEC3 in, "in"
DEBUG CR, "ft = ", DEC3 ft, "ft"

IF (((in = 3) AND (cm = 8)) OR (in = 2) OR (in = 1) ) THEN 'distances which the ping will react
FREQOUT 4, 200, 7000
GOSUB Back_pulse
GOSUB Right_pulse
GOSUB Right_pulse
GOSUB Right_pulse


ELSEIF (irDetectLeft = 0) AND (irDetectRight = 0)THEN
GOSUB Forward_pulse
HIGH 1
HIGH 11



ELSEIF (irDetectLeft = 0)THEN
GOSUB Back_pulse
GOSUB Right_pulse
HIGH 11


ELSEIF (irDetectRight = 0) THEN
GOSUB Back_pulse
GOSUB Left_pulse
HIGH 1

ELSEIF (irDetectLeft = 1) AND (irDetectRight = 1)THEN
GOSUB End_pulse
LOW 1
LOW 11

ELSE
LOW 1
LOW 11
PULSOUT 13, 850
PULSOUT 12, 650
PAUSE 15

PAUSE 100


ENDIF

LOOP

Forward_pulse:
FOR counter = 0 TO 7
PULSOUT 13, 850
PULSOUT 12, 600
PAUSE 20
NEXT
RETURN

Right_pulse:
FOR counter = 0 TO 3
PULSOUT 13, 850
PULSOUT 12, 850
PAUSE 20
NEXT
RETURN

Left_pulse:
FOR counter = 0 TO 3
PULSOUT 13, 650
PULSOUT 12, 650
PAUSE 20
NEXT
RETURN

Back_pulse:

PULSOUT 13, 650
PULSOUT 12, 850
PAUSE 15

RETURN


Stop_pulse:
PULSOUT 13, 750
PULSOUT 12, 750
PAUSE 50
RETURN

End_pulse:
FOR counter = 0 TO 5
PULSOUT 13, 850
PULSOUT 12, 600
PAUSE 50
NEXT

RETURN

well its still a prototype, but it works!!!
will accept code upgrades..