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RPi 3 using a 4.3" inch touch screen

rickleusybh

screen - How can I determine if a given touchscreen is compatible? - Stack Overflow

 

I am required to list down several alternatives to replace the current using 7" RPi touchscreen due to size constrain.

My team had been given a 4.3" screen with custom-made cover, as it'd been using by our seniors during the earlier stage of product development.

Lecturer demand us to keep the product with the 4.3" size screen during final year project exhibition, even though we are allow to run tests with the 7" RPi screen during development phase.

Our seniors said the selection of the screen they used was purely based on luck and they didn't done any research in compatibility issues, which later the lecturers questions us.

While doing some internet search about the compatibility issue, I found out that this is very confusing, because not all touchscreens are compatible. I'd encounter terms like TFT, RGB, 8080, LVDS, MIPI, etc, which I have no clue at all. But we are required to include all the findings in the FYP report.

I'd read through several websites and this question already and it's not helpinghttp://raspberrypi.stackexchange.com/questions/28/how-can-i-determine-if-a-given-touchscreen-is-compatible http://elinux.org/RPi_VerifiedPeripherals#Touch_Screenhttp://www.lxdinc.com/technical_resources/lcd_module_protocol_interfaces

How do I find out, whether a touchscreen is compatible to the Raspberry Pi? And more importantly, why and how?

Is it some kind of communication issue or connection issue or protocol?

Parents

  • In general: Raspberry pi has HDMI and "composite" out.

     

    Your screen needs that as an input to be able to work. I bought a 'composite 4.3"  lcd screen' 20 years ago, and tried it on my pi. The quality is horrible. More modern stuff may be a bit better, but part of the ugliness comes from the composite "protocol" to transfer the video data.

     

    4.3" screens usually do NOT work directly with HDMI. So you could get some sort of adapter. Those boards exist, but are usually bigger than the pi and the 4.3" screen. Not useful if you want to stay within a certain size.

     

    That leaves getting the pi to speak the protocol of the 4.3" screen. There are lots of screens that can be controlled using a few GPIOs by a microcontroller like an arduino. The PI can of course do the same as the arduino.

     

    The problem however is to get the driver for the raspberry pi. It is possible to write a driver that checks what should be on the screen periodically and then updates the screen accordingly. If you buy a 4.3" screen on Ebay suitable for raspberry pi, they will have written such a driver.

     

    I've bough such a screen, and when I was ready to try it a few months later, it turned out that as a driver they had a kernel image with the driver included. This kernel was outdated and didn't support the recent versions of the raspberry pi. And illegally they did not want to provide the source to the driver.

     

    So... If you manage to find a "4.3 inch screen for raspberry pi", be sure you check out how the software works before you buy.

     

    EDIT: I checked out the market for what's available "NOW", and it is a bit better than before. Now you can get a 4.3" screen plus HDMI converter for $33. Not a touch screen though. You'd have to look a bit further for that....

  • in reply to rew

    Thank you for the comments

    So I think I would required to check the current drivers for alternatives screen to ensure they are supported before I choose them, am I right?

     

    GPIO based screen... hmm, I guess we need to discuss onto this matter before deciding items to be included in the recommandation list

     

    Anyway, thank you.

Reply
  • in reply to rew

    Thank you for the comments

    So I think I would required to check the current drivers for alternatives screen to ensure they are supported before I choose them, am I right?

     

    GPIO based screen... hmm, I guess we need to discuss onto this matter before deciding items to be included in the recommandation list

     

    Anyway, thank you.

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