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Full Version: [help] line follower using atmega 32
rahuljin
Jul 29 2008, 4:08 PM
since my lcd project is not working, i am starting to work on a new project and also try to work on lcd side by side.

i have the following material ----
1. ir leds
2. lrds
3. high intensity leds
4. lm324n comparator(14 pin DIP)
5. atmega32 with ADC

i want to make a line follower using atmega32. can anyone provide me a circuit for it. thanks.

Ajay
Jul 30 2008, 2:50 PM
I am really thinking why your LCD program is not working, its really wired. Can you try the sample code given in LCD tutorial section? for AVR? just to check if the LCD is ok or not.

Regarding this line follower there are number of ways to make this project, as you are choosing simple switching IR signals, some use ADC etc.

I think you willl get a reference project online on that "Build your own microcontroller project" website.

rahuljin
Jul 30 2008, 4:18 PM
i have checked. you may remember that i did the same project with 89s52. when i used that code, the lcd worked correctly.

sir, it is my first project in which some sensors will be used.

now i want to use a lm324n instead of ADC. can u provide a link or tutorial for it ??

one more thing --- i heard that signal from ir led can only be recieved by ir transistor. is there any other way ?? this is better ??

Ajay
Jul 30 2008, 4:28 PM
rahuljin
Jul 31 2008, 5:27 PM
for receiving IR signal, i purchased some VS0038 ir receivers. but i didnot find any datasheet for it to use in the circuit. so please help me.



Ajay
Aug 1 2008, 3:37 PM
they are same as TSOP1738, read that datasheet.
rahuljin
Aug 1 2008, 8:04 PM
i try to test so i made a simple circuit to verify that if output is obtained or not.

i tried to measure the voltage between output and ground but nothing.

then i tried to move the ir led near to receiver, but still nothing.
any help.

pdi33
Aug 2 2008, 4:34 PM
rahuljin,
reverse the IR led connections.
it is reverse biased as per ur diagram.
rahuljin
Aug 2 2008, 4:43 PM
sorry, i draw it wrong. i wanted to correct it but the site was not opening.
so the corrected circuit---





but it is not working.
sashijoseph
Aug 4 2008, 3:34 AM
If the output's not high without the IR led,probably the ir sensor's gone kaput.
Better get the TSOP 1738 available easily,instead of these no-name Chinese lookalikes.
rahuljin
Aug 5 2008, 5:49 PM
now i get two TSOP 1738 which are costly than chinese ones.
i use a ir receiver and ir led and gave then 3.3v supply. i placed them very near each other(0.5cm aprt) and an output of 0.3v is obtained. but after removing the led, i get the same result.

than i changed the led, but same result.
after that i changed the ir recevier, but this time also the same result.

now what to do.... :mad
۞ TPS ۞
Aug 5 2008, 8:59 PM
please go through this link it may also help you
http://onlinetps.com/raghu/
rahuljin
Aug 7 2008, 3:57 PM
the TSOP1738 i bought dont hav any number on them.

i want to ask some questions ----
1. do i need 555 ic or 38khz cystall with the ir led ?

2. when i interchange the ground and vcc, i get a 3.54 vcc as output. is it working ?
also when i press the button of my sumsung tv remote there is a fall of 0.05/0.06 volts. is not it very less ?

3. in correct conditions and according to diagram i posted, i am getting a constant 0.6 volt as output and the receiver becomes very HOT. is this working?

4. then i change it to connection of TSOP 1838, the output is about 4.5 volt and when i press the button of tv remote, there is a drop of about 1 volt and i get about 3.5v output. is this the working condition ?

5. i connect the ir led to about 3 v and repeat the about three steps, but there is not volt change in the output, even after changing the ir led 3 times.is this the wrong way of sending ir signal ?

6. on net, i came across some threads in which they used a ic 555 or nand gate ic but i dont get the purpose.

plz tell me what to do now
sashijoseph
Aug 7 2008, 5:10 PM

1. do i need 555 ic or 38khz cystall with the ir led ?


Yes you need ir pulses at 38kHz.Simply powering up the ir led won't work.

2. when i interchange the ground and vcc, i get a 3.54 vcc as output. is it working ?


Just how could you do that!!! :-s
With active devices you NEVER swap gnd and +ve...that's elementary my dear Watson....
You probably have lost a few bucks here...

3. in correct conditions and according to diagram i posted, i am getting a constant 0.6 volt as output and the receiver becomes very HOT. is this working?


No...
With correct connections and without a 38k ir signal the output of the tsop should be ~5V.(Do use 5V for the tsop Vcc)

4. then i change it to connection of TSOP 1838, the output is about 4.5 volt and when i press the button of tv remote, there is a drop of about 1 volt and i get about 3.5v output. is this the working condition ?


With a presence of ir signal from the remote,the output of tsop should be close to 0V(~250mV according to datasheet)

6. on net, i came across some threads in which they used a ic 555 or nand gate ic but i dont get the purpose.


It's used to generate a 38kHz frequency for the ir led to be pulsed with.Without this the tsop won't work.

And finally RC5 works with a 36kHz modulation frequency...so you'd be better off with a 1736 if you are intending to use RC5.
btw have you visited the link Ajay posted in the previous page for line follower robot?
rahuljin
Aug 7 2008, 5:36 PM
thanks for the information and help.
yes, but that person doesnot mention about 555 or nand ic but lm324.
i think lm324n is for converting the singal to 0 or 1 at desire signal.
can it be used instead of 555 ?

from the output from the question 5, i can assum it is correctly working. i dont used any capacitor and resistors which are mentioned in datasheet. so this could be the reason.

also if it is totally drop to zero that how people use then in measuring distance ??
please correct me if i am wrong.

update--- i used a different remote and on pressing button and also put a capacitor of 4.7uF, output droped from 4.7v to 0.6v.

also i dont want to use a rc5.i just use it to check the ir receiver. i will make the source using a 555 ic at 38khz.
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