16x2 lcd with UnoR3 probs

Ok, I got the contrast working now, I can se the bars.. But to get the volts down to 4,2 on my pin 15, I needed a 560K resistor... And when I got that volt it didnt light up.
So I think my backlight must have been broken.

mysqo:
Ok, I got the contrast working now, I can se the bars.. But to get the volts down to 4,2 on my pin 15, I needed a 560K resistor... And when I got that volt it didnt light up.
So I think my backlight must have been broken.

Contrast working is good news. The lcd may be working after all. The 560K is way too big. You will need no more than 560 ohms.

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

The setup you show is exactly what one would expect There will be a pin row soldered to the LCD module and that is plugged into the solderless breadboard. The plug-in wires are then run to the pot and the Arduino.

same as my setup is what you see here above

knuckles:
same as my setup

It probably isn't the same. His works, yours doesn't, and you can't see his wiring anyway. As I have said before, the wiring is probably where the problem lies, and that clip is no help. You should be able to use the hello world sketch that comes in the examples. You don't need to download anything, and certainly not the Freetronics sketch.

The standard sketch has all the details for the wiring and thus can be used with any 16x2 LCD. While the sketch is, like tronixstuff, usually seen for use with a shield, that is immaterial. Your breadboard serves the same purpose. The code is only interested in the Arduino pins. You have to connect the correct wires from the LCD to them. There is a bit more about that here.

I think you are actually at an advantage with the bare LCD like yours. It is more flexible, and gives you more choice, than a shield.

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 !

I think you are misinterpreting something, perhaps what has to be soldered.

If you reread reply #4 you will see that it says "You must solder the connections to your LCD module."

In that case the LCD module has wires connecting the module to the breadboard while the video that you have submitted in reply #25 has pins connecting the module to the breadboard.

In reply #4 the connections (wires) are not soldered to the LCD module whereas in reply #25 the connections (pins) are soldered to the LCD module.

As you have correctly stated in both cases the wires (or pins) are simply plugged into the breadboard, not soldered.

Don

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.

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

bperrybap:
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.

I still think he faithfully followed that "really nice wiring diagram" back in the other thread --> can never get a LCD to work with UNO - #32 by bperrybap - Displays - Arduino Forum <-- and that his connections are exactly backwards. A photo would prove or disprove my theory.

Don

knuckles:
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

Arduino Projects - Arduino LCD display - YouTube

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.

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 --> can never get a LCD to work with UNO - #7 by system - Displays - Arduino Forum <-- before it was removed by a different moderator.

Don

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 .

knuckles:
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?

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

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

knuckles:
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.

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 .

knuckles:
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.