Anyone got experience with >4 inch displays?

Hardware
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Hi folks,

I just ordered my Spark Core and I’m very excited to give it a try. (Even though I have some basic education in electronics, I haven’t done anything in the last 6 years)

So my first question refers to displays, specifically those displays with high quality like OLED. The thing is that I want to build a simple application that shows a 0-6 digit number on black background, preferrably on a display >4 inch.

Does anyone of you have any experience with this kind of task? I saw that there is different standards like I2C or SPI, but I have no idea yet how hard it is to get a display running with these standards.

Thanks,
bernie

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if you search around, the screens are usually UART, SPI or I2C which makes it much easier to interact and implement.

Look at adafruit, seeedstudio and sparkfun for the displays offered and that might give you a better idea. ^^

2 Likes
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@bernie, you will find it difficult to find OLED displays larger than 3.2" diagonal like this one for example.

You can, however, find large TFT LCD display modules like this one which can use I2C or SPI communications depending on how it is configured.

What’s nice is both are graphical so you can display your digits in any font or look you want. :smile:

1 Like
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Awesome, thanks for your help!
I’m gonna try the OLED and see how it works.

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thanks - What about displays like this one? http://www.buydisplay.com/default/7-inch-lcd-module-capacitive-touch-screen-panel-i2c-spi-serialI am new to spark and was wondering if there’s support for this touch screen in libraries etc. Has anyone “played” with this or similar?

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I’d think this is not a display but only a cap touch digitizer panel and to use it you’d rather want the Core to talk to a suitable controler than to the digitizer direct.

Edit: You’ve just updated the link, but now it’s a broken link :wink:

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@ScruffR the moment I posted I realized it was just the touch panel… not the whole thing.
here the one I am wondering about
http://www.buydisplay.com/default/7-inch-lcd-module-capacitive-touch-screen-panel-i2c-spi-serial

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@BayerischBier, there are different ways to do touch screens. One is to read the voltages from the touch membrane directly. Another is to use a touch screen interface chip which simplifies the interface and does all the heavy lifting. Without too much promotion, I have pledged on Indiegogo for a different type of display (similar to 4D Systems) which is smart display implementing a Human-Machine Interface. This moves the entire GUI work to the display device :wink:

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@peekay123 , I have seen the 4D intelligent displays. I really like the 7" and dislike the price :wink:

Will Core or Photon libraries support the Nextion?

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As I see it, for the basic usage you’d only need serial communication but no real library.

AFAIK the Arduino lib only wraps the serial communication up into easy to remember functions, which shouldn’t need too much Spark porting :wink:

But you could have a look at this demo, which shows native and lib communication

http://blog.iteadstudio.com/product-preview-nextion-in-an-arduino-project-2/

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@ScruffR and @BayerischBier, @ScruffR is partly correct. A library must be used to manage outgoing and incoming display events (touch, etc). However, all this is done via a Serial port so a Spark port will be straight forward. If you are familiar with the 4D Systems Spark library (I ported it) then you will understand the need for it. :smiley:

2 Likes
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That was a textbook example, how to contradict diplomatically :wink:

Of course Paul is right, since there is some proper “formating” and “vocabulary” for the serial commands required, the library is “needed” to save you a lot of headache.

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Hey everyone I bought a nextion 4.3" and have received it. I haven’t plugged it in but I have played with their editor and it’s not all that bad.

Has anyone else gotten one yet? Any good results?

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@Bspranger, I have six 4.3" Nextions and absolutely have it working! I ported their Arduino weather app to the Photon/Core and posted it on their forum. :smile:

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@peekay123 I got your example working with the weather! It is pretty sweet!

Do you know if the nextion allows you to change an image’s location via the serial port? I haven’t seen that feature.

I know the gauges allow rotation but do they allow you to rotate any image?

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@Bspranger, for that question, you need to go to the Nextion forum and wiki. They also have a new (easily ported) Arduino library. :smiley:

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sigh… just asked about ported libs and an example in the other thread… will check this out, thanks @peekay123

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@BayerischBier, the Nextion library is super easy to port:

  1. In NexTouch.h, change #include <Arduino.h> to #include "application.h"

  2. In NexSerialConfig.h, change #define nexSerial Serial2 to #define nexSerial Serial1 if you are connecting the Nextion to the Rx/Tx lines of the Photon.

That’s it! :slight_smile:

1 Like
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@peekay123 have you done any popCallBacks with the Nextion yet? I just want to be able to know when a button is pushed and send back vars to fill in blank text fields like t0.txt=myVar.

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I can vouch for the displays from buydisplay.com that @peekay123 mentioned, they work flawlessly.
You must however keep in mind that large pixel densities (larger displays) take longer to update up to a point where it’s barely usable . A 480x272 SPI/I2C screen would refresh at sluggish rates.

If you don’t mind seeing your digits update one pixel row at a time, the suggested display will be perfect for your application :slight_smile:
The effect can be seen here: https://www.youtube.com/watch?v=GYDLHMxKCaU, it would be a bit faster though