Line follower with Photoresistors

julius.meinl

Hi,

I would like to show you my line follower with Photoresistors. (It's my DIY construction so I don't know is it a good topic there ).



Only what you need to build this sensor are 3 photoresistors (e.g VT935G-B).



The ciruit is simple:



My program is using RCTIME Command and copare time from 3 circiut .

 time1 VAR Word
 time2 VAR Word
 time3 VAR Word

 DO

     'first photoresistor

HIGH 15
PAUSE 3
RCTIME 15,1, time1


  'second photoresistor
HIGH 6
PAUSE 3
RCTIME 6,1, time2


  'third photoresistor
HIGH 0
PAUSE 3
RCTIME 0,1, time3


     DEBUG HOME,"time1=  ",  DEC5 time1 , "time2=  ",  DEC5 time2,"time3=  ",  DEC5 time3



IF   (time1 > time2 ) AND ( time1> time3 ) THEN
PULSOUT 13, 650 ' Left rotate
PULSOUT 12, 650
HIGH 14
ENDIF

IF ( time3 > time2 )  AND ( time3 > time1)  THEN
PULSOUT 13, 850 ' Right rotate
PULSOUT 12, 850
HIGH   1
ENDIF


IF (time2 > time1) AND ( time2> time3 )   THEN
PULSOUT 13, 850 ' Forward
PULSOUT 12, 650
HIGH    7
ENDIF


LOOP

There is a short video:

www.youtube.com/watch?v=sKapEdJaOzg


Of course It's only prototype, but I think this sensor can be use in diffrent project with boe-bot

SRLM

How much does the antistatic foam affect your readings? I'd think a non conductive material would make it easier to get identical results with multiple modules. Nice job.

Humanoido

Very good prototype. I like the excellent design with pure simplicity and it can use simple parts available from Parallax for the Boe-Bot. The CaS cell is commonly available. Is that conductive foam used to run the wires through? Thanks for sharing the images and code.

humanoido

julius.meinl

This foam is only used to maintain the structure ( I try to built this sensor very fast, becouse it's a part of much bigger project )

There is the same sensor but soldered to copper wire:




In this design, photoresistors have a common mass, so you don't have to conect photoresistor to Vss

(under the robot you can see additional wire, but it's a part from diffrent projekt )