Pages: [1] 2   Go Down
Author Topic: Reading 10+ LDR with Arduino  (Read 1420 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 40
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Hey Folks,

I am brainstorming for a project that I am about to do, and It would need me to read 10+ LDRs. As There arent that many analogue input pins, whats the workaround that I can put to use? smiley-sad

Thanks  smiley
Logged

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 309
Posts: 26538
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Use a Mega
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Offline Offline
Newbie
*
Karma: 0
Posts: 40
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Use a Mega

I am assuming there is a workaround than buying another Arduino.  smiley-confuse
Logged

BHZ, MG, Brazil
Offline Offline
Sr. Member
****
Karma: 10
Posts: 346
Android developer; Arduino enthusiast
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Use a Mega

Too expensive, and the guy already has an Arduino (not Mega, I suppose)

My suggestion is to use a multiplexer IC, like the CD4051.

Personally, I like and use the MAX4617 (datasheet)
Logged

Learn to live: Live to learn.
Showing off my work: http://arduino.cc/forum/index.php/topic,126197.0.html

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 309
Posts: 26538
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

External analogue muxes, like a couple of 4051.

Quote
Too expensive, and the guy already has an Arduino
He never stated that.
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Offline Offline
Newbie
*
Karma: 0
Posts: 40
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Quote
As There arent that many analogue input pins

By that, I meant I had an Arduino. Sorry for not making it clear. I have an Arduino UNO R3.

So a multiplexer is what I should use?

Since I am new to all these, can someone give me a little insight? a circuit diagram or something so?

Cheers! smiley
Logged

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 309
Posts: 26538
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

http://playground.arduino.cc/learning/4051
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Offline Offline
Sr. Member
****
Karma: 6
Posts: 429
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Is this for a (low res) vision sensor?

I remember seeing something like that on BBC Click that controlled an array of mirrors (I think)
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 40
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Seems like this is what I am looking for smiley-grin

Can I breadboard it? or it should be bought as a chip? (For both saving money and for satisfaction of doing it.)
Logged

Copenhagen / Denmark
Offline Offline
Edison Member
*
Karma: 6
Posts: 2360
Do it !
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

You can breadboard it with just the chip.

The CD4067 has 16 "inputs" if you need more than 8
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 40
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

You can breadboard it with just the chip.

The CD4067 has 16 "inputs" if you need more than 8

8 would be fine, 16 would be better if there isnt much price difference with the chip.

Sorry for asking this, but I will appreciate a right circuit diagram for bread boarding it, because I am new to this. I tend to make mistakes when it comes to where I should be applying the voltage and so. (Happened before smiley-grin )

Thanks a lot smiley


ADD : Or the 4051 would be fine because after a bit of reading, I see the 16 inputs one needs 4 pins from my arduino.
« Last Edit: April 03, 2013, 01:08:49 pm by xkishorx » Logged

BHZ, MG, Brazil
Offline Offline
Sr. Member
****
Karma: 10
Posts: 346
Android developer; Arduino enthusiast
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

ADD : Or the 4051 would be fine because after a bit of reading, I see the 16 inputs one needs 4 pins from my arduino.

of the 4 pins required, 3 of them are digital pins, OUTPUT, used to select which input in the 4051 (or 4050) is to be read. The other pin is one of the Analog inputs of the arduino that will receive the output of the 4051 for its selected input.
Logged

Learn to live: Live to learn.
Showing off my work: http://arduino.cc/forum/index.php/topic,126197.0.html

Offline Offline
Newbie
*
Karma: 0
Posts: 40
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

ADD : Or the 4051 would be fine because after a bit of reading, I see the 16 inputs one needs 4 pins from my arduino.

of the 4 pins required, 3 of them are digital pins, OUTPUT, used to select which input in the 4051 (or 4050) is to be read. The other pin is one of the Analog inputs of the arduino that will receive the output of the 4051 for its selected input.


I have bit of an understanding about Multiplexer now, but I thought that was 4 output Pins and another 1 analogue pin. For my project, I can give 3 Output pins for this. Yeah, thats fine. Looking forward for a clear circuit diagram if one is available smiley
Logged

Global Moderator
UK
Offline Offline
Brattain Member
*****
Karma: 309
Posts: 26538
I don't think you connected the grounds, Dave.
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

For two muxes, you'll need four digital outputs and two analogue inputs.
Logged

"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

Offline Offline
Newbie
*
Karma: 0
Posts: 40
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

For two muxes, you'll need four digital outputs and two analogue inputs.

Point taken.

But I am looking for 1 Input instead of 2. Do I still need 4 digital outputs? Well, but the other member here said they are 3 outputs and 1 input.

Logged

Pages: [1] 2   Go Up
Jump to: