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Topic: Multiple LCD's (Read 1 time) previous topic - next topic

Kcarp

I am new to Ardunio, but loving what I see so far.

I just purchased a Uno R3.  I have been messing around with it and I think it is awesome!

I have not ordered any LCD's yet. However, I am looking to display 2 different LCD's, use 2 different temp sensors, and run a couple relays for power outlets.  Will the Arduino be sufficient for this setup?

Thanks.

pylon

If you use I2C LCD displays and DS18B20 temperature sensors you're fine, else you may run out of pins, depending on what "a couple of" is actually in numbers. Standard LCDs with 4-bit parallel interface use at least 6 pins, thermistors use an analog pin, so you need 14 pin out of 20 just for them. Usually you want the serial interface for debugging, make 2 additional pins, leaving 4 for your relays. Is this a couple of?

Riva


If you use I2C LCD displays and DS18B20 temperature sensors you're fine, else you may run out of pins, depending on what "a couple of" is actually in numbers. Standard LCDs with 4-bit parallel interface use at least 6 pins, thermistors use an analog pin, so you need 14 pin out of 20 just for them. Usually you want the serial interface for debugging, make 2 additional pins, leaving 4 for your relays. Is this a couple of?

Could you parallel the Data, R & R/W pins to both LCD's and have separate E line for each LCD's. It's not a thing I have tried but data should only get latched when the (E)nable pin is pulsed so should be able to steer the data to the required LCD. This would save 5 pins.
http://forum.arduino.cc/index.php?action=unread;boards=5,67,10,11,66,12,15,17,21,22,23,24,25,29;ALL

dhenry

Quote
I am looking to display 2 different LCD's, use 2 different temp sensors, and run a couple relays for power outlets.  Will the Arduino be sufficient for this setup?


that would depend on whath kind of LCDs, temp sensors / relays you are talking about. Some of them can take a lot of pins.

utwg

Should be enough. 2 x 5 pins for the LCDs and 2 x 1 pin for the temperature sensor.
electronics: http://www.microtivity.com

Kcarp

The temp sensors need two pins I believe.... Input and output.... I will link the components I bought when I get home from work

Tom Carpenter

If they are standard LCDs that work with the LiquidCrystal library, then they can share the data pins and the R/S pin. Each one simply has its own enable pin which the arduino then uses to select which to talk to. On one arduino uno alone you could have up to 9 such displays, your two temperature sensors and still be able to communicate with the computer.
~Tom~

Kcarp

https://www.sparkfun.com/products/11042
http://www.adafruit.com/products/165

I need two of each of these on the Arduino.  And I also need two LCD's, which I have not purchased yet. 

liudr

The comments you are receiving are all about character displays. All suggestions are good. You may also use serial displays with addressing capability. My phi-panel LCD backpack has that feature. You only need 1 wire to drive up to 255 displays  XD XD

If you want a graphical display, you need to indicate which one.

Kcarp

Yes everybody's comments are great and helpful.  I said I would list what I bought so I did.

I only need to output text on the LCD's.

dhenry

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which I have not purchased yet.


It is hard to help you without knowing specifics about the lcds you intend to connect.

In general, there is nothing inherent in arduinos to prevent multiple devices (identical or otherwise) to be connected.

Kcarp

I'm open to suggestions on the LCD's.

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