Hello all, What is the largest touch screen that will work well with mbed?

-Rich

Size is mostly irrelivent,

basicaly a RESISTIVE touch screen is two vairiable resistors,

one for the X,

annother for Y.

resolution becomes an issue as size increaces, assuminy you have matching graphical display resolution.

Ceri

Larger display size usually means that you also need or get higher resolution (nr of pixels). Depending on the interface to the screen (serial SPI or 8, 16 or 18bits parallel) it will use up more or less pins on the mbed and it may take a lot of time to update the screen (eg 320 x 240 x n bits). Screen updates may take a lot of time and make the system seem slow/unresponsive. See http://mbed.org/cookbook/SMARTGPU You may want to look into separate displaycontrollers that can interface to regular VGA displays and offer a higher level of interface to the mbed (eg. draw lines, rectangles etc). See http://mbed.org/cookbook/uVGAII. The touchscreen will need a separate interface. Some add-on touchscreens offer an RS232 or USB interface.

Maybe I don't exactly need the "largest" LCD Trouch screen. My project is moving forward and now I am requiring a way to display my sensor data and etc... I was considering coding a C# sharp program for the computer to display values and etc... Then I started to think perhaps having mbed display the values right at the mbed unit. I looked at my Arduino LCD Shield from a past Arduino project and it seemed too small and I wanted more of a graphical display to give my mbed project some spunk. Perhaps I should have asked, from your guys experience what screen size should be efficient to display sensor data at a large enough font and have a way to edit settings for my sensor readings and etc...

Hello Richard,

did You see http://mbed.org/cookbook/SPI-driven-QVGA-TFT from Peter Drescher? I think it is exactly what You want. Especially check bottom of that page for more pictures.

I think 3,2 inch screen should be big enough for good readings. Also think about RAM memmory consumption if You want any fullscreen picture on background because if picture doesn't fit in memmorey it must be loaded from say SD card for example and it is more slow. Not so much slow but You see how picture is drawed on screen. Externall memmory can help here. Be patient with my English please, I am from Czech Republic.

No worries about your English. Thank you for your input. I will research that screen further.

To my knowledge, the best bet for one large screen with a lot of pixels is to use an LPC1788, LPC4088 or an STM32F407 or similar since they have dedicated LCD controllers. I've seen LPC4088 board with a 7" 800x480 display, but I have not tried any of them before.

If you use a QVGA SPI TFT display at around 3" or so, and it is not quite enough display area, you could also consider combining a few of them to display different sensor readings?

Using the LPC4088 QuickStart Board you can use a 7 inch display.

Have a look at the LPC4088 QSB Base Board product page and you can see which display options we have available. There is also a video which shows a 4.3 inch display used with the board.

Andreas @ Embedded Artists

I've had goods successes with the RA8875 based Display. This controller has several hardware graphics features - line, text, rectangle, circle, triangle, resistive or capacitive touch, and more. This permits good machine graphics, like are described above. Resolution of inexpensive displays range from 480x272 to 800x480, and size from 4.3 inch to 8 inch.