Author Topic: About I.R. sensors.......  (Read 3884 times)

0 Members and 1 Guest are viewing this topic.

Offline RITESH29Topic starter

  • Robot Overlord
  • ****
  • Posts: 152
  • Helpful? 0
Re: About I.R. sensors.......
« Reply #60 on: March 25, 2012, 09:21:06 AM »
Hi,

As my sensor is working fine I need to couple sensor with L293 without uC for testing purpose.
So, i have connected the L293 as shown in image. i have changed the pin 8 to 5V then 12V
the output of LM234 is connected to LED with 570ohms. which is working fine. after this the pin 1 of LM324 is given to pin 2 of L293.

I am not understanding the motor with sensor is not working??, the H-BRIDGES are working fine!!

Offline Soeren

  • Supreme Robot
  • *****
  • Posts: 4,672
  • Helpful? 227
  • Mind Reading: 0.0
Re: About I.R. sensors.......
« Reply #61 on: March 25, 2012, 02:46:34 PM »
Hi,

As my sensor is working fine I need to couple sensor with L293 without uC for testing purpose.
So, i have connected the L293 as shown in image. i have changed the pin 8 to 5V then 12V
the output of LM234 is connected to LED with 570ohms. which is working fine. after this the pin 1 of LM324 is given to pin 2 of L293.

I am not understanding the motor with sensor is not working??, the H-BRIDGES are working fine!!
Are you saying that the L293 drives the motor if you set pin 2 high and low manually, but not when the LM324 drives it?
What's with the LED and resistor (that you claim to be 570 Ohm??)?
Is that still on when you connect it to the L293?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline RITESH29Topic starter

  • Robot Overlord
  • ****
  • Posts: 152
  • Helpful? 0
Re: About I.R. sensors.......
« Reply #62 on: March 25, 2012, 11:27:31 PM »
Quote
Are you saying that the L293 drives the motor if you set pin 2 high and low manually

Yes!!
Quote
but not when the LM324 drives it?
yes!!
Quote
What's with the LED and resistor (that you claim to be 570 Ohm??)?
at the output of LM324 pin 1...
Quote
Is that still on when you connect it to the L293?
yes and the LED then go off.

Note:-i am using 5V from 7805...!!

Offline Soeren

  • Supreme Robot
  • *****
  • Posts: 4,672
  • Helpful? 227
  • Mind Reading: 0.0
Re: About I.R. sensors.......
« Reply #63 on: March 26, 2012, 07:20:39 AM »
Hi,

Quote
Is that still on when you connect it to the L293?
yes and the LED then go off.

Note:-i am using 5V from 7805...!!
OK.
Your resistor is most definitely not 570 Ohm and why do I care? - Because it troubles me that you may get other things wrong and it's hard to troubleshoot on false assumptions, so please be precise.

Your first step (as always when something don't work) is to measure, to get a view of what's going on, so measure the input of the L293 (with the LM324 connected) - what voltages do you see (dark/light)?
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline RITESH29Topic starter

  • Robot Overlord
  • ****
  • Posts: 152
  • Helpful? 0
Re: About I.R. sensors.......
« Reply #64 on: March 26, 2012, 07:30:51 AM »
Hi again,
Quote
Your first step (as always when something don't work) is to measure, to get a view of what's going on, so measure the input of the L293 (with the LM324 connected) - what voltages do you see (dark/light)?

I have used L298 before it input sensitivity is very very cool, even when i use few k resistance to input side it work fine!!
But here in L293 it does not work with single 1K Resistance so, i think that must be the problem.
Anyway the low output of l324 is ~.2v and to 4.5V max.

Offline Soeren

  • Supreme Robot
  • *****
  • Posts: 4,672
  • Helpful? 227
  • Mind Reading: 0.0
Re: About I.R. sensors.......
« Reply #65 on: March 26, 2012, 04:37:46 PM »
Hi,

But here in L293 it does not work with single 1K Resistance so, i think that must be the problem.
Anyway the low output of l324 is ~.2v and to 4.5V max.
Is the LED plus resistor connected between the output of the LM324 and positive supply?

Anyway, after you measured that, you looked in the datasheet (of course) and read that the input to the L293 must be max. 1.5V to be read as a low and at least 2.3V to e read as high - then you cooked up a get-me-by solution, with a diode between the output of the LM324 (anode) and the input of the L293 (cathode) and added a resistor of 10k..100k from that input to ground, to get your input to be ~1.3V to ~3.8V and thus within specs for the L293. Good job ;D
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline RITESH29Topic starter

  • Robot Overlord
  • ****
  • Posts: 152
  • Helpful? 0
Re: About I.R. sensors.......
« Reply #66 on: March 26, 2012, 07:55:16 PM »
Will 5V supply will work fine with both sensors and L293?? from 7805!!
as at 12V the RPM of more increases!

Offline Soeren

  • Supreme Robot
  • *****
  • Posts: 4,672
  • Helpful? 227
  • Mind Reading: 0.0
Re: About I.R. sensors.......
« Reply #67 on: March 26, 2012, 09:58:48 PM »
Will 5V supply will work fine with both sensors and L293?? from 7805!!
as at 12V the RPM of more increases!
You really dislike experiments, I gather  ::)

If you just read the datasheets, all would be clear!
Use 12V only at the motor voltage pin and only if you want 12V. Since you don't, just hook it up with 5V and test.

Next time you wanna ask something, do take a glance at the datasheet and/or give Google a spin first. I don't mind helping, but I don't even spoon-feed my grandson (as it shows in the attached pic from his 1 year birthday some years ago :)), as that is no way to learn (messy in the beginning perhaps, but it gives faster and better results).
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline RITESH29Topic starter

  • Robot Overlord
  • ****
  • Posts: 152
  • Helpful? 0
Re: About I.R. sensors.......
« Reply #68 on: March 27, 2012, 11:11:58 AM »
Hi again,

There is some problem the out put of 7805 fall to ~2.2V while connecting it to L293, some times.
and when it was  ~4.8V the L293 was working fine with sensors.without any diode and pull down Resistance!!

Offline Soeren

  • Supreme Robot
  • *****
  • Posts: 4,672
  • Helpful? 227
  • Mind Reading: 0.0
Re: About I.R. sensors.......
« Reply #69 on: March 27, 2012, 08:31:18 PM »
Hi,

There is some problem the out put of 7805 fall to ~2.2V while connecting it to L293, some times.
and when it was  ~4.8V the L293 was working fine with sensors.without any diode and pull down Resistance!!
Would that "some times" be when you connect a motor, or is it entirely random?
The motor may be loading either your regulator or your power source too much.
So...
Find when it's happening and if it's (only) when the motor is connected, measure input and output of your regulator when it happens.

What power source do you use in front of the regulator, a mains supply or battery and i the latter, which type, capacity and state of charge.

When something acts up, your best friend is pen, paper and a voltmeter. Making systematic measurements will tell you where the problem is.


If this turns out to be a simple case of a flat battery, one of us should have red ears (and it isn't me :))
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

Offline RITESH29Topic starter

  • Robot Overlord
  • ****
  • Posts: 152
  • Helpful? 0
Re: About I.R. sensors.......
« Reply #70 on: March 28, 2012, 02:39:00 AM »
Quote
What power source do you use in front of the regulator, a mains supply or battery and i the latter, which type, capacity and state of charge.

Hi,

I am using 12V 2Amps adapter!!

Offline Soeren

  • Supreme Robot
  • *****
  • Posts: 4,672
  • Helpful? 227
  • Mind Reading: 0.0
Re: About I.R. sensors.......
« Reply #71 on: March 28, 2012, 07:01:07 AM »
Quote
What power source do you use in front of the regulator, a mains supply or battery and i the latter, which type, capacity and state of charge.

Hi,

I am using 12V 2Amps adapter!!
OK and what do you measure on each side of the regulator?

Please measure the motor draw as well?

Does the motor run for a short time before the problem appear, or is it right from the start?

I wonder if the regulator is entering thermal shut down. With 12V in, you drop 7V over the regulator. If the motor takes eg. 500mA, the regulator has to dissipate 3.5W of heat, which means you need to mount it on a small heat sink.
If it gets too hot internal, it shuts down and with a large current draw and a large voltage drop, this can happen while the outside is only slightly warm.
Measure, measure measure - the only way to find out what's causing the problem.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


Get Your Ad Here