choosing a LCD TFT Touchscreen shield

It's heading into a different area, but this is quite an interesting shield: Batsocks - TellyMate Shield

It's a 38*25 character (not pixels, but character) composite video TV shield for an Arduino - have a look at the examples page

Yes, I have seen that shield and have it on my list but unfortunately my project opportunity for using it has passed so I can't justify buying one now.

Mowcius

has anybody thought of attaching an arduino to a USB to VGA converter?

Somebody did:
http://microvga.com/arduino

Somebody did:
http://microvga.com/arduino

I stand corrected.

Thanks Florin :slight_smile:

Hi,

In response to the original question, I have one of the nuelectronic tft/lcd shields (the 2.4" version) and found it an interesting sheild to use. It does however have a number of drawbacks, fristly there are very few i/o pins left. I seem to recall only about 3 or 4 analogue pins including the ones used for I2C communications.

The distance between the 2 rows of pins is slightly wider than it should be for an arduino shield. The pins are bent inwards slightly to compensate but still tries to force the arduino connectors outwards.

The display was stuck to the PCB using double sided tape which tended to lift around the connector end so a dab of glue fixed this.

The library originally available was pretty basic, there was a recent update and it has improved with more demos showing a simple button meny and text (although the text demo didnt seem to work for me). There is one issue I have found with the bitmap demo in that it displays the image in reverse.

I've not had chance to play with the updated library yet other than running the demos.

The old library seemed to have problems with the touchscreen reading functions being a bit on the noisy side.

I did do a write up some time ago which needs a bit of an update now the library has been updated, its at http://blog.thiseldo.co.uk/?p=450

Hope this helps :smiley:

Andy

Well it is much cheaper than the other alternatives. I would not expect many free pins and it might take some time to get some decent libraries and example code...

Mowciuus

It is a very good price, especially the 2.4" version. I couldnt justify the extra tenner for the larger screen for something I just wanted to have a play with.

As with all these shields, someone is likely to write a better library. I had already written a couple of simple demos that list the contents of the SD card and display animated buttons that move when you click on them.

I'll probably take it with me on holiday in a couple of weeks and have a look at the code then. It wont be the first time I've taken an arduino on a camping holiday with me :wink:

Cheers

Andy

Thanks for the replys and info about the shield

I haven't yet looked at the code to see how the nuelectronics shield actually works, but it might be possible to use a shift register to minimise the amount of pins used.

but it might be possible to use a shift register to minimise the amount of pins used

Unlikely but possible I suppose. It wouldn't then be a shield though...

Hi,

I was wondering if that touchscreen is capacitive or resistive. Also how long it might take to change from one image to another?
Any info is much appreciated.

-jh

I was wondering if that touchscreen is capacitive or resistive

It's resistive. I do not know of any small capacitive screens you can buy (apart from the ones stuck on phones)

Mowcius

I have the nuelectronic shield.

It's a cheap 2.4/2.8" touchshield AndyL (thanks AndyL!) covered most of the relevant points.

There are very few I/O lines remaining, mostly the A/D lines and looking at the schematic possibly digital pin 8 (Andy?), though I have not tested this yet. Fortunately although the shield uses the serial port pins 0 and 1 you can still program the arduino without unplugging the shield.

other points?

NewSoftSerial works perfectly well off the analog pins (have a GPS unit running with no problems)

Graphics library is very basic - line, circle, box, rounded box with no support for line thickness.

Text support is better, in particular using custom fonts is very simple with the option to include only the characters you actually need to save memory (eg a large display font with only 0-9 or a simple symbol font with a few button icons)

The Analog pins include the I2C pins, so an I2C muliplexer would give you plenty of other inputs.

Refresh is a buit slow and the graphics / SD Card / Touchscreen libraries eat quite a lot of program space. I have mine running off a 1000mAh lipo, but if power is not an issue it might be worth connecting a second arduino over serial or I2C and having one drive the LCD and one run the code (I think the liquidware touchshield slide does this?)

Looking at the spec sheet for the LCD driver it appears to have an SPI mode, which would obviously save a lot of pins. I may look into this if I ever have the time....

Top of my head that is it, if you have any specific questions then feel free to ask- if I can't answer them straight away I am more than willing to have a bit of a tinker

Unlikely but possible I suppose. It wouldn't then be a shield though...

It's not a shield, it doesn't fit!

I ordered one and it arrived yesterday - I didn't want to force it into the arduino in case it damaged one or the other. I've got it running off a breadboard.

I haven't done anything other than get the demos running so far (but not the SD card one, can't find a spare card ::)). Initially I just want the screen so I'll be looking at seeing how few pins it needs for that.

The fit is not perfect and something that I came across when I first started to use it. On the arduino the 2 rows of connectors are 48mm apart, the pins on the LCD/tft shield are 50mm apart and on mine were angled inwards. This then forces the connectors on the arduino outwards.

I think this was done on the PCB to accommodate the 2.8" and 2.4" displays using the same pcb. If they had just opted for only the 2.4" then the pcb could have been made with the correct spacing. Just my 2p/2c worth!

Cheers

Andy

Re: the fit

The pins fitted are quite long, Just bend the shorter row of pins 90 degrees towards the board centre and then another 90 to the vertical 2mm in. Fits a Pro board perfectly, though this was a permanent solder-in-place situation, not sure how the bends would stand up to repeated pluging/unplugging into header sockets.

I just ordered the 2.8" yesterday. I'm glad there are other people who've purchased this product and are posting recently. I've not has as much luck with my other projects. let's keep this thread alive!

I'm glad there are other people who've purchased this product and are posting recently.

There were some other updates outside this thread recently but it appears as though the people in this thread have one (I don't though... Might get one soon but no need for it atm) so they could probably help, maybe :sunglasses:

Okay so i've been able to test out the libraries and everything works. Now I'm trying to figure out which pins are actually needed so I can use the other pins. I've guessed that it doesnt need the vin and one ground and the 3.3v pin. Im afraid of bending the other pins to test it out. does anyone know for sure which pins are not needed by the display on the 2.8 model?

it doesnt need analogue pins 3 to 6

hmm does anyone have luck with a bigger font?
I tried to import a Arial 50 into the Font editor and include it into the Arduino Sketch but now no FOnt is Displayed.

What am I doing wrong?

Thx
Andy