Do big displays for microcontrollers exist?

[e100]

I'm working on my first 'big' microcontroller project that needs to display 20 values that can be easily seen at a glance, but I cannot find a suitably large display that has an SPI, I2c or serial interface. Displays over 3" in size seem to only support HDMI/VGA interfaces.
At the moment I'm displaying the information on a VT100 terminal emulator on a laptop computer connected via a USB/serial converter but don't want this to be the final solution.

Mike

[Signal32]

There are no big displays that have interfaces such as SPI I2C or serial. The reason is because they wouldn't be able to be driven via SPI and certainly not I2C or serial.
At 320*240 resolution with 16 bits per pixel and 60fps you would need a ~73 MHZ data stream which is pushing it for SPI.
However there are solutions that basically have a high resolution display + built in display driver that expose a SPI/serial port which you can use to send high level GUI commands to (draw text, draw rectangle, etc).
Something like: http://www.ampdisplay.com/documents/pdf/DMT48270C043_03WN.pdf

[mark03]

Large display != many pixels.

Perhaps an LED display of some sort?  I think there are also electrophoretic (e-ink) displays intended for retail price display and that sort of thing, with digits instead of pixels.  Problem with e-ink is the market is still too niche, hence the devices tend to be highly proprietary, with top-secret datasheets, back-room deals, no availability in quantities less than one gazillion, etc.  I think there were some dev kits (Energy Micro, now Silicon Labs, had one a while back), if you're willing to pay top dollar.

I wonder if you could mount one of those small OLED displays from ebay behind a fresnel magnifier.

[Scrts]

I'm working on my first 'big' microcontroller project that needs to display 20 values that can be easily seen at a glance, but I cannot find a suitably large display that has an SPI, I2c or serial interface. Displays over 3" in size seem to only support HDMI/VGA interfaces.
At the moment I'm displaying the information on a VT100 terminal emulator on a laptop computer connected via a USB/serial converter but don't want this to be the final solution.

Mike

This is relatively easy to do with FPGA and a video frame buffer.

[CaptCrash]

4D Systems make a range of reasonable sized displays.  Depending on how big you want.
Up to about 7" I think and can be driven from micros with a minimum of effort

[Kilrah]

Would need to know what he wants to display, what "large" is (are we talking 7" or a scoreboard that has to be seen from the other end of the stadium?) and what kind of resolution he wants.  Numbers or alphanumeric? Maybe the "flippy-dot" displays Dave received are an option? 7-segment LED displays?

But yeah, apart from specialized industrial style applications (=rather expensive made-to-order stuff) large cheap display usually means high resolution, and the interface that goes with it. Throw a raspi at it and you're done...

[CJay]

Would need to know what he wants to display, what "large" is (are we talking 7" or a scoreboard that has to be seen from the other end of the stadium?) and what kind of resolution he wants.  Numbers or alphanumeric? Maybe the "flippy-dot" displays Dave received are an option? 7-segment LED displays?

But yeah, apart from specialized industrial style applications (=rather expensive made-to-order stuff) large cheap display usually means high resolution, and the interface that goes with it. Throw a raspi at it and you're done...

Seconded, RasPi Zero, cheap and reliable.

Or, I have explored those 2.4" SPI displays, you can throw a bitmap at them quickly so I wonder if the OP has enough horsepower available to 'multiplex' them?

[e100]

Would need to know what he wants to display, what "large" is (are we talking 7" or a scoreboard that has to be seen from the other end of the stadium?) and what kind of resolution he wants.  Numbers or alphanumeric? Maybe the "flippy-dot" displays Dave received are an option? 7-segment LED displays?

But yeah, apart from specialized industrial style applications (=rather expensive made-to-order stuff) large cheap display usually means high resolution, and the interface that goes with it. Throw a raspi at it and you're done...

Readable at 50cm so the character height needs to be at least 5mm. Being able to distinguish colours at 3 meters would also be good.
15 x 15 cm (6" x 6") is probably the minimum size required. Bigger would give more flexibility for displaying debug strings.

Someone put together a project that does serial to VT100 emulation with a VGA output. 
http://geoffg.net/terminal.html
presumably because there are no commercial products that do this already?


 

[MT]

I have a different aproach, if LCD manufacturers so desire they could implement QUAD SPI who certanily would be able to support large displays.
Im just baffled the industry havent abandoned the "yee ol' 8bit MCU interface on the basic 16x2 LCDs etc, etc, etc, boog standard LCD's etc, etc,.

[RogerRowland]

Nextion may be an option?

https://nextion.itead.cc/

[janoc]

I have a different aproach, if LCD manufacturers so desire they could implement QUAD SPI who certanily would be able to support large displays.
Im just baffled the industry havent abandoned the "yee ol' 8bit MCU interface on the basic 16x2 LCDs etc, etc, etc, boog standard LCD's etc, etc,.

Why would they do that when there is MIPI DSI, DisplayPort, HDMI and who knows how many other standards for this already, with displays widely available (mostly thanks to smartphones/tablets).

Sure, you can't drive a MIPI or DisplayPort from an Arduino, but so what? If you are building a system requiring that kind of high resolution display, you would need a lot of RAM and a fast CPU to drive it anyway. At that point you can as well choose a processor that actually has the required interfaces.

The old MCU interface on the character LCDs is there because the Hitachi controller is 20 years old, proven quantity, cheap as a dirt and works well enough for the job. If you need a serial interface, adding a shift register is trivial. Change for the sake of change is not always beneficial.

[MT]

For ordinary MCU's. I dont have HDMI on my STM32 F303, why would i boog up tons of pins on my F429 just to get som paint on the pixel? Some times you might just want to do what the OP want to do without using anything you sugested.Why would there not be an incentive for yet another standard? We all luuuve standards dont we, just one more! Cludgefy a clean design with yet annother shift register is usless, it doesnt cost much to implement 2x16 with serial, actually it allready exist. Progress janoc! Progress!

Just found that FT80x and FT81x has QSPI.

[richardman]

We will have a solution that hopefully can demo in early October. I will send you PM and make announcement here when appropriate.

[MK14]

I'm working on my first 'big' microcontroller project that needs to display 20 values that can be easily seen at a glance, but I cannot find a suitably large display that has an SPI, I2c or serial interface. Displays over 3" in size seem to only support HDMI/VGA interfaces.
At the moment I'm displaying the information on a VT100 terminal emulator on a laptop computer connected via a USB/serial converter but don't want this to be the final solution.

Mike

One solution, is to make the microcontroller a Raspberry PI 3 (£30/$35), but there are others as well. They can then have HDMI outputs, along with graphics chips built in, and operating systems, such as Linux. So that you can readily use normal computer monitors and/or TVs, as big as you like.
You can even get ones based on more conventional microcontrollers (with in some cases, lots of I/O and that type of functionality), such as Pic32's, made by e.g. Olimex.

Or use a large LED matrix display, with SPI (or other interface types), as the large display, on the non-HDMI equipped microcontroller.

[David Hess]

What about 7 and 16 segment LED displays?

[MT]

[Delta]

K.I.S.S.

http://www.411techsystems.com/Extra-Large-Font-20x2-HD44780-LCD-wBack-Light_p_102.html

[langwadt]

I'm working on my first 'big' microcontroller project that needs to display 20 values that can be easily seen at a glance, but I cannot find a suitably large display that has an SPI, I2c or serial interface. Displays over 3" in size seem to only support HDMI/VGA interfaces.
At the moment I'm displaying the information on a VT100 terminal emulator on a laptop computer connected via a USB/serial converter but don't want this to be the final solution.

Mike

http://www.buydisplay.com/default/7-inch-lcd-module-capacitive-touch-screen-panel-i2c-spi-serial

https://github.com/sumotoy/RA8875

[mariush]

Like others said, you could use 14-16 segment digits to display your numbers, and you could add a small microcontroller in your design to act as a "driver" to do the multiplexing (if needed) for your 20 values, but it could get expensive.
Here's some examples, they're all 10-14mm tall digits : http://uk.farnell.com/webapp/wcs/stores/servlet/Search?catalogId=15001&langId=44&storeId=10151&categoryId=700000006097&sort=P_PRICE&eq=N%3D204194%2B110321669%2B2031%26amp%3BNs%3DP_PRICE_FARNELL_UK%257c0%26amp%3BNtpc%3D1%26amp%3BNtpr%3D1&showResults=true&aa=true&pf=110321473,110321669&vw=

Lots of alphanumeric LCD displays that have big fonts, up to around 14.5mm per digit, and transmissive or transflective so you can choose if you want to make them with backlight or not .. you can buy them split in rows like these ones here: http://uk.farnell.com/alphanumeric-lcd-displays  or as graphical where you can flip any pixel on the screen: http://uk.farnell.com/graphic-lcd-displays
Most of these work with 4 bit or 8 bit parallel and some have chip select so it's easy to work with them , some have i2c, spi etc

[Psi]

Theres a few projects to draw lines and text on any tv over composite video using an ATMega/arduino

There is also the max7456 ic which does the same thing in hardware but is text only. It has built in fonts and you control over SPI.

Max7456 are expensive from legit sources. Pretty much everyone uses the china knockoff instead.

[janoc]

Progress janoc! Progress!

Just found that FT80x and FT81x has QSPI.

I guess that's a different meaning of progress then - changing from something that works and is widely available to something that almost nobody supports. But I digress ...

Also we were talking about large, high resolution screens, not driving 16x2 over HDMI or MIPI. Try to drive something of size of a FullHD display over QSPI and you will see ... There is a reason why almost all smartphone displays are MIPI today.

[MT]

I dont argue aginst any MIPI whatever,just that QSPI would be neat, but if you dont like QSPI i think you will miss something very useable.
I bet there are loads of licenses to pay with the systems you sugested, not to mention all the software layers while there is none particular
with QSPI i recall.   Besides this is about OP request not that he wanted to implement MIPI for a LED display.

Retire HD44780 now!

[e100]

Thanks to all who gave suggestions.
To summarise, 4dsystems and Nextion have 'smart' displays that go up to 7" in size, although setting these up seems like a major development in itself.

To go beyond 7" requires the use of a single board Linux computer running a terminal emulator, or a laptop running Windows/Linux.

As far as I can tell VT100 style terminals with LCD screens don't exist. Second hand terminals from yesteryear are available, but use CRT screens and are therefore bulky and power hungry.

Chromebooks appear to have some degree of support for USB to serial adaptors and the "Beagle term" terminal plugin for the Chrome browser should in theory work, but I don't want to spend the money only to find out that it doesn't.

Android tablets don't support any kind of serial interface.
Overall it makes me wonder if adding a $15 Wiznet W5100 ethernet interface is the way to go, that way anything that supports TCPIP and a terminal emulator can be used to display information. The W5100 does all the heavy lifting of TCPIP thus conserving memory on the microcontroller.

[nfmax]

I'm working on my first 'big' microcontroller project that needs to display 20 values that can be easily seen at a glance, but I cannot find a suitably large display that has an SPI, I2c or serial interface. Displays over 3" in size seem to only support HDMI/VGA interfaces.
At the moment I'm displaying the information on a VT100 terminal emulator on a laptop computer connected via a USB/serial converter but don't want this to be the final solution.

Mike

You could use something like a Raspberry Pi or BeagleBoneBlack running Linux and driving an LCD panel over HDMI. You would need an application that reads from the serial port and writes the text to a full screen window (which might be nothing more than a terminal emulator like PuTTY!). Start the application from the init/systemd script and away you go. Sure, there may be far more transistors, computing power, and software in this solution than in your microcontroller application, but so what? It's cheap (and low powered)

[MK14]

As far as I can tell VT100 style terminals with LCD screens don't exist

Do you want just text/numerical OUTPUT ?
Or does it need to input (using a keyboard) into your microcontroller program, as well ?

Some of the LCD and VFD type of screens, are similar to VT100 style terminals (WITHOUT the keyboard). Because they can have serial type inputs, such as SPI. The SPI or I2C replacing what use to be a RS232 type of serial connection. But there is more complexity, to get the best results. See LCD datasheets, for information about this. (i.e. not just characters, but special commands, such as clear screen, reverse char draw, etc).

If you use a Raspberry PI 3, the output goes straight to the screen, via the HDMI port, by default (once linux has booted and you open a terminal window or full screen). Just like a PC.

I.e. you install the (micro) SD card with some kind of Linux on it (readily available for PI), and use GCC for your C program. PrintF/Cout, will then go straight onto your HDMI monitor screen. Via some kind of terminal window or full screen, depending on how the GCC and the resultant executable is being run.