Comments on: IR sensors

By: asciole

asciole — Thu, 18 Feb 2010 23:02:08 +0000

can this be used as a clock pulse?

By: cognoscis

cognoscis — Wed, 12 Aug 2009 07:14:18 +0000

Raktim,

Once you have the sensors, you will want to think about a logic that will help the bot to navigate the line. I will create a new post explaining a simple line follower. I hope that will help. Keep checking this site or else subscribe to it to get the feeds directly to your mail

Regards

By: Raktim

Raktim — Tue, 11 Aug 2009 18:17:07 +0000

sir,
i’m just a beginner in autonomous robotcs, i’m tryng to make a line follower.
i’ve been able to figure out the sensor part of it only…now how do i proceed…can u plz help me out….

By: IR sensors « Cognoscis

IR sensors « Cognoscis — Wed, 05 Aug 2009 15:30:24 +0000

[...] IR sensors [...]

By: Ravi Revelly from india

Ravi Revelly from india — Sat, 21 Feb 2009 09:44:34 +0000

hello sir,

thanks for your post,it will be very use full to my project,thank you very much again..

By: cognoscis

cognoscis — Fri, 30 Jan 2009 07:17:02 +0000

Well, this is actually very new problem I have seen

Anyways, you can indeed increase the current by employing a buffer between the comparator and the microcontroller. Here is the data sheet of one such buffer IC. This one has 4 buffers packaged in one IC. You also get more number of buffers in a single package. So, you can choose whichever you fell is right for your board. Here is the link to the one I mentioned

http://www.nxp.com/#/pip/pip=pip=74HC_HCT126_CNV_2|pp=[t=pip,i=74HC_HCT126_CNV_2]

By: Pragyajit Das

Pragyajit Das — Fri, 30 Jan 2009 01:15:35 +0000

Sir,
According to your steps I have checked everything and find no problem in microcontroller. I doubt that the current drive from the output of LM339D is not enough to drive the port of microcontroller.
Is there any way to increase the current drive?

By: cognoscis

cognoscis — Mon, 26 Jan 2009 13:50:12 +0000

Okay, there maybe some problem grounding problem. You can try something else, try to use some other port. Also, you try to run a program and take the input and see if you can make an LED glow. Also, the ports of the microcontroller must be programmed as input ports. So, cross check all of these.

By: Pragyajit Das

Pragyajit Das — Mon, 26 Jan 2009 13:19:06 +0000

Sir,
First of all, I am using the port P1.0 of microcontroller AT89C52. In this port, the is no need of using pull up resistor.
Using 10K pot, I fix the reference voltage at 3.0V.
Now when I donot connect the output of the comparator to the microcontroller, the output of the comparator shows high voltage when the IR sensor is obstructed.
As soon as I connect it to the microcontroller the final output goes down to about 0.5V.
What shoud I do now to get out from this problem?

By: cognoscis

cognoscis — Mon, 26 Jan 2009 06:25:25 +0000

Pragyajit

I can think of a number of reasons for this. So, here is what I want you to do. Make sure again that you have connected the pull up resistor R3 as shown in the diagram. Since the pin floats for a HIGH output, it wont be able to drive the microcontroller.

If you have done that, now please cross check the potentiometer as described in the post and check the output across the comparator IC. If that gives the proper output then you need to consider the microcontroller.

Certain microcontrollers also have floating HIGH pins just like comparator. So, check the datacheet and see if the ports need to be pulled up using a pull up resistors. 8051 ’s PORT 0 is like that. You need external pull up resistors to drive it HIGH

Hope this solves your problem