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Value of the photo resistor...??????

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nirmal_rockin

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photoresistor circuit

Can any one pls tell wat value of photo resistor can be added to the sensor circuit of the line follower.....
pls help
thanks.....
 

pranam77

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typical photoresistor values with a laser

Anyways...the picture is not visible. You may use any value of Photo transistor. Only thing you have to do is to adjust the resistance with pull up or downs and get the required logic out when the track is detected and the other logic when track is not detected. Good luck
 

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Photo resistor? or transistor? and no readable picture in the post.
 

nirmal_rockin

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pranam77 said:
Anyways...the picture is not visible. You may use any value of Photo transistor. Only thing you have to do is to adjust the resistance with pull up or downs and get the required logic out when the track is detected and the other logic when track is not detected. Good luck
sorry by mistake i forgot to add the schematic...
now the schematic is updated.....
can you pls tell now......
 

pranam77

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Are you refering to a LDR when you say Photo resistor? You may use any photo diode and vary the variable pot to get different "Logic's" when the track is detected and when not.
 

nirmal_rockin

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pranam77 said:
Are you refering to a LDR when you say Photo resistor? You may use any photo diode and vary the variable pot to get different "Logic's" when the track is detected and when not.
yes i'm specifying LDR only....
 

seadolphine2000

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The LDR has a value of 1KOhm with direct light from a Laser pointer and, can have a value up to 1MOhm without the light.
I measured these values myself when experimenting my Laser Burglar alarm.

Just one concern, as I can see from the schematic, you are using an "InfraRed LED". I don't think that the photoresistor (LDR) will detect it. Probably, you have to use phototransistor.

Please, anyone correct me if I'm wrong.

Hope this helps.
 

qdnboy

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I would say replace the photo resistor with a phototransistor too. Phototransistor reacts much quicker to light than photoresistor.
 

pranam77

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qdnboy said:
I would say replace the photo resistor with a phototransistor too. Phototransistor reacts much quicker to light than photoresistor.
Yes..when you use IR LED as the transmitter, it is good to use Photo diode as a receiver.
 

vipinsaini

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Dear,u can use anyone from phototransistor/photodiodes.
Both have good quick quick response time.
Someone say good to the phototransistor or some say to the photoresistor.

Thanks
Er.VIPIN SAINI
 

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