Comments on: Using the Analog To Digital Converter.

By: Avinash

Avinash — Wed, 10 Feb 2010 13:54:19 +0000

@Samuel,

good question. I recommend using the other pins of ADC PORT as INPUT only. And use some other I/O port for OUTPUT purpose. Once I tried to do the same thing. One ADC was used as ANALOG IN while the other pins carried medium frequency DIGITAL OUTPUT signal (to switch seven segment displays). In this configuration the ADC result were not constant, it was fluctuating. When I made the other PINs of ADC free and used some other PORts the problem was solved!
So this info may be useful for you.

By: Samuel Skånberg

Samuel Skånberg — Wed, 10 Feb 2010 13:45:38 +0000

Very nice tutorial!

I have one question, is it possible to use the other pins to other stuff (like lighting LEDs) if I only use one pin for the AD conversion? Or will the AD conversion use the whole port?

I use an AT Mega 16 and the port A is used for AD conversion as well. Can I use port A both to do AD conversion on pin 0 and light a LED on port 1?

Kind regards

By: Avinash

Avinash — Wed, 10 Feb 2010 10:55:21 +0000

@ABY
please see article on LCD interfacing first. their you will get details on lcd connections

By: ABY

ABY — Wed, 10 Feb 2010 10:15:30 +0000

i have gone through the program.its so simple and quickly understood, but only confusion is that which port is assigned to take output,and how to connect that port to LCD…?

By: Andrew

Andrew — Fri, 18 Dec 2009 15:23:57 +0000

yeah tryed it and then noticed some mistakes in a code l wrote it works nicely thx

By: Avinash

Avinash — Fri, 18 Dec 2009 13:26:13 +0000

@Andrew

Please disconnect everything from the ADC port. The value now should show random value. Now connect it directly to Vcc the value should be 1023 and then connect (ADC0) to the GND pin it should show 0.

By: Andrew

Andrew — Fri, 18 Dec 2009 12:22:41 +0000

Hi
l am just starting to work with atmega16 controller and got a hang first tutorials and desided to try this one to but then l connect everything together but then l start a program a result l get is always 1023 and l tryed hooking up a pontiometer insted a LRD and turning it but always l get only 1023 is there something l do wrong with my software? maybe with registers? l used exactly a same code as your posted in this tutorial and l got nothing. Connections is ok

By: mohan

mohan — Tue, 15 Dec 2009 10:39:43 +0000

hi avinash, good work.
hi i am very poor in basic electronics and also in practicle(circuit designing)….
hi can u sugest me some good websites that gives some idea on basics and circuit design..

By: Phill

Phill — Fri, 11 Dec 2009 14:40:05 +0000

Hi, I’ve build a filtering ciruit and attached it to the adc, connected to the adc is a resistor, on one side of this i’m getting 2.5v on the micro side im getting 0v. if I remove the micro, this goes up to 2.5v. The signal is at approx 0.2mA is this enough? What do i need to set the DDR to for the adc port? I want to use some of the other portbits as digital inputs. Thanks for any help!

By: Saif ullah khalid

Saif ullah khalid — Wed, 21 Oct 2009 16:32:12 +0000

hi pranav,
U better visit delhi,s lajpat rai market for required stuff ass you can found every thing required there…and that cheaper then any where else u will get

By: Avinash

Avinash — Tue, 20 Oct 2009 10:37:24 +0000

Hello Pranav,
Many people in India face same problem. Thats why I started a Online Shop. You can visit it here
http://shop.extremeelectronics.co.in/

I was very angry by local dealers not giving correct parts and also charge so high.

By: Pranav

Pranav — Tue, 20 Oct 2009 08:25:29 +0000

Hey Avinash,
Where do you buy all your electronics stuff in India? I live near Dehradun and for me it seems impossible to get any stuff, no hobby shops around!! Is there any safe online shop which deals with it and do you know any place around Delhi or preferably Lucknow?
I was able to get in touch with ATmega16 there in Lucknow for my surprise!! :p

By: Avinash

Avinash — Mon, 28 Sep 2009 07:12:23 +0000

@Jing

3v is 60% of 5v (Ref Voltage) so 60% of 1024 (Max Value for 10BIT A/D) is required value. 60% of 1024 is 614.4 = 614 and its HEX equivalent is 266. You must write 0×266 (prefix by 0x) in ‘C’ so that compiler knows it is a HEX and not decimal.

By: jing jie

jing jie — Mon, 28 Sep 2009 06:58:45 +0000

i am connecting a LDR to a PIC. i want to compare the value that the LDR to the preset value. how do i represent this preset value in hex? for example, if the value of LDR is less than 3V, then do the following commands. how to concert the 3V to hex value? thanks.

By: thiru

thiru — Fri, 11 Sep 2009 11:44:30 +0000

thanks for your help

By: sanjay

sanjay — Sun, 26 Jul 2009 19:31:02 +0000

hi avinash
my question is how to get ADC from multiple channels simultaneously.i used to get but the result of all the channel was same .

By: Avinash

Avinash — Thu, 04 Jun 2009 03:01:33 +0000

@Johan

here LDR is changing resistance according to light but ADC can measure Voltage only. To convert RESISTANCE to VOLTAGE we have used a Voltage Divider.

By: Avinash

Avinash — Thu, 04 Jun 2009 02:58:10 +0000

@Johan

Here LDR and R(100K) froms a Voltage Divider. More info here http://en.wikipedia.org/wiki/Voltage_divider

By: Johan

Johan — Wed, 03 Jun 2009 08:49:46 +0000

Hello Avinash!
Great tutorials! A question regarding “Fig: LDR Connected to ADC of AVR”. What I see there is 100 kohm resitor going to ground. Is that a standard resitor value for all types of ADC connections? I have seen 10 kohm resitor values as well in schematics. What I try to say is: should it always be a resistor placed (to ground) like that when using AVR adc?

Regards
Johan

By: Avinash

Avinash — Tue, 02 Jun 2009 00:47:37 +0000

Conver the binary no to a string say if ADC read out is 792 (stored in int) break it to ‘7′, ‘9′, ‘2′ ij ASCII and sent to LCD

The algo would be

int a;


a=ReadADC();

while(a) { char ch; ch=a%10; // divide by 10 and strore remainder in ch, 792%10=2 so u get the last digit ch=ch=10; // remove last digit, 792/10= 79 }