Comments on: Sensor – LDR

By: Cognoscis » Blog Archive » Simple line follower

Cognoscis » Blog Archive » Simple line follower — Sat, 07 Nov 2009 13:33:42 +0000

[...] a black background). For this, LDR or IR sensors can be used. For construction of LDR sensor click here and for IR click here. Now, we have two sensors which are like two eyes of our bot. Using these [...]

By: Sensor – LDR « Cognoscis

Sensor – LDR « Cognoscis — Wed, 05 Aug 2009 15:32:08 +0000

[...] Sensors – LDR [...]

By: How to make a PCB at home « Cognoscis

How to make a PCB at home « Cognoscis — Sat, 04 Jul 2009 06:09:56 +0000

[...] IR signal for modulated IR sensor explained in my previous post. The second picture is a part of LDR sensors I made for my line follower robot. The picture has a comparator circuit and a motor driver circuit [...]

By: Sanjana Sharma

Sanjana Sharma — Sun, 03 May 2009 06:32:38 +0000

Hey,
Actually we got d circuit made from sum1….now dat person is saying that drs no problem in d ADC..its d OP07 which is getting burnt on connecting to ADC….what mite be d reason here?We have our project submission 2mrw…n sumthing or d odr gets spoilt every now n then..plz sort this out…..if possible you can send me ur email id..will directly contact u via messenger

By: cognoscis

cognoscis — Sat, 02 May 2009 17:07:30 +0000

Sanjana,

The reason for that happening is obviously over current. As I have mentioned before, LDR is just a resistor. When light falls on it, its resistance will become almost zero and hence a lot of current will flow into the ADC. But, this problem might also be due to incorrect biasing. place a 10k? potentiometer in series to that LDR input that goes into your ADC. Initially keep it at maximum and see if your IC heats up. If it does, then probably you must cross check your circuit for any places where there might be short circuit. Else, slowly reduce its resistance till you get proper output from the ADC.

If you are using ADC because you want EXACT value of the current coming into the circuit then its OK. If you are using ADC only to convert your AC to DC, then I suggest you switch to the simple comparator that I have shown in this post. All the same, if you can provide your circuit diagram and the part number of the ADC then I can try to pin point the bug in your circuit

By: Sanjana Sharma

Sanjana Sharma — Sat, 02 May 2009 16:14:21 +0000

Hey,
I need ur help as early as possible…In order to convert the LDR output to digital we r using an analog to digital convertor…bt den on connecting it to d adc d ic is getting burnt..can u tell d reason for it…

By: cognoscis

cognoscis — Wed, 07 Jan 2009 05:12:55 +0000

HI,

LDR is just a resistor, so whatever voltage you apply, it will work well… You can try the normal one you have and if it doesnt work, you can get back to me

By: tinus

tinus — Wed, 07 Jan 2009 02:41:10 +0000

Hey,I’m after a LDR that can work with 3V only. Is there anything on the market? thanks guys.

By: joe

joe — Sat, 23 Aug 2008 22:30:56 +0000

Absolutely love your technique! Surprised I didn’t come across your blog earlier! Thanks for sharing and keep writing!

By: IR sensors « Cognoscis’s Weblog

IR sensors « Cognoscis’s Weblog — Fri, 13 Jun 2008 11:39:14 +0000

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