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Author Topic: 16x2 lcd with UnoR3 probs  (Read 5389 times)
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Central MN, USA
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To make it a bit more clear for the newbies regarding connection, only these are proper for connecting two metals for electrical conduction:

Solder the metals together.
Eg. The pins in that video are soldered to the metal contacts on the display.

Use spring-loaded mechanism to hold one metal against another.
Eg. The row of pins are pushed into breadboard holes. There are spring clips under the holes to hold metals together. Same goes with the jumper wires inserted in the breadboard.
Eg. There is a "spring" type of contact inside Arduino board's female headers. If you insert a square pin in a female header, the "spring" holds the square pin. Round pins will have worse contact with arduino headers so you may expect some issues.

Certainly you may use welding (fusing two metals) or gluing (conductive glues), or other less obvious spring-load ways (wire-wrapping, wire nuts) but if you just jam the lead of a wire into a hole, it won't be sufficient. My rule of thumb is: if you can easily pull the contacts apart, they are likely not making good electrical contacts. Hope it helps.
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knuckles,
It takes only a few minutes to wire up an LCD to an Arduino
It takes even less time to for an experience person to be able to detect
a wiring error or mismatched LiquidCrystal constructor if
all the non working information supplied.
The needed information is:
- the full sketch being used
- A clear photo that shows all the wiring

If you would supply both of those your problem would be resolved
very quickly.

--- bill
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knuckles,
The needed information is:
- the full sketch being used
- A clear photo that shows all the wiring

floresta said it, Nick Gammon said it, now Bill said it again. I wonder how many forum members will it take to get knuckles to respond to these reasonable requests.
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I still think he faithfully followed that "really nice wiring diagram" back in the other thread --> http://arduino.cc/forum/index.php/topic,136463.msg1026929.html#msg1026929 <--  and that his connections are exactly backwards.  A photo would prove or disprove my theory.

Don
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he has the same problem as me, and i have noted the stern instructions that all the wires should be soldered to the LCD ,but having looked at the videos on youtube regarding  connecting UNO to LCD ,none of them are soldered ,just having wires plugged in to a breadboard and they are all working just fine !
so how do you explain that ?

here is one thats the same as mine except no hello world display


Nick Gammon asked you to:

"@OP (knuckles): start a new thread please, describing your problem in detail.

Post a link to the exact LCD you are using.

Post a photo of your connections. A clear photo.

Post the code you are using, inside code tags.

Thanks."

You have hijacked someone else's thread.  This is rude.
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Quote
You have hijacked someone else's thread.  This is rude.

It's not nearly as rude as the language he used in reply#6 of the original thread --> http://arduino.cc/forum/index.php/topic,136463.msg1025335.html#msg1025335 <-- before it was removed by a different moderator.

Don 
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look guys its a simple wiring job ,NO, the pins 1-16 are not connected backwards do you think i am stupid ?,i have 1-16 numbered on both sides of the display and theyre all wired u p as the youtube example above ,all very simple stuff .i have worked in electrical engineering all my life .
the codeing is as i have posted .i will try the different numbers in the code when i have time to do it ,i have more important things to do ,like wife and family, job and earning ,and other hobbies ,arduino stuff is low down my priorty of things to do .
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Dee Why NSW
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theyre all wired up as the youtube example above ,all very simple stuff

In that event, my curiosity is getting the better of me. Looking at the youtube, there is a long blue wire connected to #6 "E" on the display. Can you tell me what Arduino pin this is connected to?
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Quote
do you think i am stupid

Well, you are the one who brought it up so here is your answer.  

I do not think you are stupid, I think you are ignorant. 

You are also proving that you are intransigent.


Don

« Last Edit: December 11, 2012, 10:34:19 am by floresta » Logged

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i am chucking them back in the shoebox till next year i cant afford to waste any more time on these LCD displays .the display on the Pololu orangatan works ok for now .
i might try a few new ones next year in case theyre faulty .
thanks for your input anyway
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i am chucking them back in the shoebox till next year i cant afford to waste any more time on these LCD displays .the display on the Pololu orangatan works ok for now .
i might try a few new ones next year in case theyre faulty .
thanks for your input anyway


I felt bad that you didn't get a good experience with arduino projects. If you did, it could take up a lot of your free time and provide both fun and functionality. As everyone else here must be, you are the master of your own domain, i.e. your job and family besides being good at wiring. I am sure that everyone in your circle respects you. But you are in a new place now, this forum. All that respect you receive automatically from your job and family is left where they are and new respect is earned not brought here.

You didn't do it the right way from the start. If you showed a picture or two, your code accompanying the pictures, you will be well respected among us as an eager learner and people usually bend backwards to help you. You didn't. After multiple members requesting photos you didn't do it, only quoting you are good with wiring, which we don't know. We don't know your name, your face or what you are good at. What me know is what you posted, which is very little about this project you are doing. Tell me that we should simply trust you with your wiring. How does that sound to you if it were someone new at your work telling you they know everything and you should put full trust on them. As experienced at work as you are, this may have been the first time you are removed from your own comfort zone in your own home or work space and have to be treated as a newbie. You probably experience that a lot if you have to frequently change jobs.

I am not calling you stupid or anything, maybe newbie shock. Stupid is reserved for repeated offenders. You are only upsetting some of us with one thing and we forget and forgive or in my case just forget. I am hoping you will come back with some other projects to share and learn with us soon.
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situation now resolved after i bought a cheapie display of ebay ,it was a 5 minute job to get it working ,looks like a faulty display was the problem.
all sketches working fine with the new display .
« Last Edit: December 13, 2012, 09:16:58 am by knuckles » Logged

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situation now resolved after i bought a cheapie display of ebay ,it was a 5 minute job to get it working ,looks like a faulty display was the problem.
all sketches working fine with the new display .


Happy for your.
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Something else to consider.

When you see the row of pins start at #15 & #16, then 1-14, it might be a non-backlit LCD display.

I have several different 16x2 character displays, and of the 3 that are not backlit, 2 have the goofy pin orientation.

With those pin 15 & 16 are not connected.  
Pin 1 & 5 - ground
pin 3 - 10k pot OR resistor to ground (8k-9k)
pin 2 - 5v
pins 4,6,11-14 connected to arduino digital pins

Adafruit has a wonderful tutorial which I still use as a reference.  Never hurts to double check connections before heating the iron.

http://learn.adafruit.com/character-lcds/wiring-a-character-lcd
« Last Edit: December 18, 2012, 01:44:12 am by JD3 » Logged

That little black caterpillar you just stepped on will set you back a few bucks....

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Something else to consider.

When you see the row of pins start at #15 & #16, then 1-14, it might be a non-backlit LCD display.

I have several different 16x2 character displays, and of the 3 that are not backlit, 2 have the goofy pin orientation.

With those pin 15 & 16 are not connected.  
Pin 1 & 5 - ground
pin 3 - 10k pot OR resistor to ground (8k-9k)
pin 2 - 5v
pins 4,6,11-14 connected to arduino digital pins

Adafruit has a wonderful tutorial which I still use as a reference.  Never hurts to double check connections before heating the iron.

http://learn.adafruit.com/character-lcds/wiring-a-character-lcd
The LCD interface as designed by Hitachi is and always has been 14 pins.  The original backlights were electroluminescent and required a high voltage (>100 v) to operate.  The connections were at the end of the display.  When LED backlights became common pins 15 and 16 were added but those pins have nothing to do with the LCD.

Some displays have two rows of 7 (or 8 ) pins at the end of the display but most have one row of 14 (or 16) pins along the edge.  From what I have seen the majority of displays have those 14 (or 16) pins at the upper left edge of the display and the pins are in numerical order starting with pin 1 near the edge of the board and with pin 14 (or 16) near the center.

I have also noticed that the displays with the pins at the lower left edge of the display are the ones that are likely to have their pins in a different order and the order of the pins is not always the same.  This appears to be the kind of display that you have.  Other than the pin order, you have described what are perfectly ordinary LCD connections.  You have to pay special attention to the markings on the pc board and/or the datasheet with these.

The Adafruit tutorials are quite helpful but you have to be careful when it comes to wiring the backlight.  The tutorial has evolved over the years and the pictures have pretty much stayed the same while the text seems to vary a bit. The displays that they sell typically have a current limiting resistor for the backlight on the pc board so there is no need for an external resistor and none is shown in the photographs.  Their text currently does mention that some (I believe this should be most) displays require an external resistor but this text seems to come and go or maybe I just missed it.

Also, be aware that the photos in that tutorial up to the 'Bus Wiring' section all show the display upside down.  The last photograph in the 'Contrast Circuit' section shows the single row of blocks that you should expect to see in the upper row but they appear to be in the lower row because the display is upside down.


Don
« Last Edit: December 18, 2012, 09:36:32 am by floresta » Logged

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