Which touch screen?

General project help for Adafruit customers

Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.
User avatar
NX
 
Posts: 9
Joined: Wed Jul 15, 2015 7:31 pm

Which touch screen?

Post by NX »

I am new to arduino & all of the shields and stuff. I am not new to electronics or embedded cpu programming.

What I want to do is add a touch screen to what has been to date, an interface of actual knobs & push buttons and I want to eliminate those knobs & push buttons. There is an additional requirement of being able to read stored user entered phrases. The phrases at most would be 20 characters long. If it were not for the phrases I imagine the physical size of the display could be quite small. Each phrase while viewed/edited/created could occupy the entire screen for legibility. Touching the screen reverts it to what ever.

Also part of the UI are slider controls for a few variables. These are discreet values so no floating point adjustments for the foreseeable.

On the touch screen I imagine push buttons or typical screen buttons. I think because of this, the touch interface should be capacitive?? Versus resistive. My understanding is that resistive works best with a stylist. I don't want a stylist.

Last, minimal size give the above. Maybe a ~4" display would work? But this is part of the advice I am looking for. As well as capacitive or resistive? I also do not want a breakout board so an Arduino + what ever else for a vertical stack would be great. Ideally I would like to be pointed to just buy this Arduino and this display. I am not expecting a perfectly optimized set of part the 1st time thru, but like a more experienced opinion than what I have which is NO experience with Arduino & pieces.

User avatar
adafruit_support_rick
 
Posts: 35092
Joined: Tue Mar 15, 2011 11:42 am

Re: Which touch screen?

Post by adafruit_support_rick »

This is the largest cap touch TFT shield we have for Arduino - it's 2.8"
https://www.adafruit.com/products/1947

We have some example code illustrating use of the display, but you're mostly on your own in developing GUI components. Sliders and buttons aren't that difficult.

As far as the Arduino is concerned, it really depends on how large your code is going to be. The Arduino Uno has 32K of flash and 2K of SRAM. About 4K of the flash is reserved for the bootloader. The Arduino Leonardo is similar, but has 2.5K of SRAM. Both the Uno and the Leonardo have the same footprint as the TFT shield. The Arduino Mega 2560 has 256K flash and 8K SRAM, but the form factor is a little larger.

Have a look at our Learn Arduino tutorials to get oriented:
https://learn.adafruit.com/lesson-0-getting-started

User avatar
NX
 
Posts: 9
Joined: Wed Jul 15, 2015 7:31 pm

Re: Which touch screen?

Post by NX »

Thanks for this advice, it is exactly what I was looking for. Straight forward & simple. I will get Leonardo w/ headers & the 2.8" cap touch display.

More to the project, sound is needed. Not full hi fidelity, but just a tone (a clean pure tone) that can be turned on/off via programming. Some variability to the tone would be good in a range mostly from 5oo Hz to 2 KHz. Possibly a headset or ear buds :( would be easiest?

Optional extra is XBee ... adapter & module of course. This is to control a remote device that must be turned on/off in sync with the tone. Any guesses about latency from the controlled processor pin to the switched a pin on the remote? I am sure that I can figure that out later. I am only wondering if someone has an idea.

I understand that any of this can be stacked up separately, but for this project the display + sound + XBee are all needed. I am thinking that this might look like some kind of Frankenstein thing >2" high? Not a deal killer and just wondering what I am getting into.

User avatar
adafruit_support_rick
 
Posts: 35092
Joined: Tue Mar 15, 2011 11:42 am

Re: Which touch screen?

Post by adafruit_support_rick »

Hmmm. There are no 'shields' for XBee modules. You'd use our XBee adapter module and wire it to the rest of your boards:
https://www.adafruit.com/products/126

There are a few ways to do sound. The Leonardo has PWM output pins. You could get a square-wave out of them. Or you could use our Music Maker shield, which has everything you want and can generate tones via MIDI under software control. You can get it with out without an amp (both have headphone output).

With Amp:
https://www.adafruit.com/products/1788
Without Amp:
https://www.adafruit.com/products/1790

XBee latency for pin-passing is pretty low, but I don't have a hard number for you.

You'll have to get a set of stacking headers for the Music Maker shield so you can stack the Uno, Music Maker and Display
https://www.adafruit.com/product/85

If you want, you can probably attach the XBee adapter to a proto shield for stacking purposes:
https://www.adafruit.com/product/2077
That comes with stacking headers, but you might want to stack in an extra set for clearance. Yes, you'll have a pretty tall stack, but it ought to work.

User avatar
NX
 
Posts: 9
Joined: Wed Jul 15, 2015 7:31 pm

Re: Which touch screen?

Post by NX »

I am little confused with "... use our XBee adapter module and wire it ...". That XBee adapter module looks like it plugs in to the stack like any other board. Is that what you mean?

For the "controlled" XBee, What is the minimum? Is an Arduino even needed? There could be reasons for an exchange of a bit of data.

Thank you for allowing me to take advantage of your advice. I am using this to build an order. I am good programmer and don't see any of these options as being difficult ... very exciting.

User avatar
DuaneDegn
 
Posts: 141
Joined: Thu Aug 02, 2012 1:39 pm

Re: Which touch screen?

Post by DuaneDegn »

What is the XBee controlling? XBees are generally used to send serial data but I think they also have pins which can be set high or low (I think they have PWM on at least one pin but I'm not positive about this). I think to access these extra pins, you need to use API mode (IIRC).

I'm personally all in favor of making Frankenstein touchscreen creations but there are likely times when a smartphone could take the place of a stack of boards and even cost less than the stack of boards.

I have recently been using MIT's App Inventor and I've been surprised how easy it is to make an Android application. It wouldn't be as much fun as making your own contraption but by using a smartphone and a Bluetooth module, the Android could communicate with your other device wirelessly. In this case you would need a microcontroller to receive the Bluetooth commands. Yes, I agree the smartphone idea is lame, though it could be less expensive (and possibly faster to implement) than a DIY creation.

User avatar
DuaneDegn
 
Posts: 141
Joined: Thu Aug 02, 2012 1:39 pm

Re: Which touch screen?

Post by DuaneDegn »

Make sure and check out the Arduin-o-Phone tutorial. I thought it was a great example of using a touchscreen.

User avatar
adafruit_support_rick
 
Posts: 35092
Joined: Tue Mar 15, 2011 11:42 am

Re: Which touch screen?

Post by adafruit_support_rick »

NX wrote:I am little confused with "... use our XBee adapter module and wire it ...". That XBee adapter module looks like it plugs in to the stack like any other board. Is that what you mean?
No, the XBee adapter is quite a bit smaller than a shield, and doesn't have the pinout. The headers are where you plug in the XBee module itself

There are a couple of ways you can use an XBee. Normally, you use it as an RF modem. In that case, you need a microcontroller to send and receive the serial data.
You can also use 'pin passing', in which the XBee replicates GPIO events to another XBee module. So, you set a pin high on XBee 1, and the corresponding pin goes high on XBee 2. That doesn't require a microcontroller.

User avatar
NX
 
Posts: 9
Joined: Wed Jul 15, 2015 7:31 pm

Re: Which touch screen?

Post by NX »

Probable final question before I plunge, is there a stacking limit of shields onto something as the Leonardo? Is there something like a fan out limit?

This is what I am wondering about;
Display + cap. touch shield
Sound shield
XBee shield (from some place)
Battery charger shield
Leonardo

User avatar
adafruit_support_rick
 
Posts: 35092
Joined: Tue Mar 15, 2011 11:42 am

Re: Which touch screen?

Post by adafruit_support_rick »

There's no particular limit, other than available power from the Leonardo's voltage regulator. Really the only thing to be aware of is pin conflicts between shields.

The cap touch shield uses the SPI pins and the I2C pins (which are buses and can be shared with other shields), along with pins 10 and 9. So your other shields can't use 10 and 9.

If you want to use the SD card on the TFT, then that uses pin 4, and your other shields can't use pin 4. If you don't use the SD on the TFT, then pin 4 is available.

Many shields allow you to re-map signals to other pins, but that's not possible with the TFT shield

User avatar
NX
 
Posts: 9
Joined: Wed Jul 15, 2015 7:31 pm

Re: Which touch screen?

Post by NX »

Rick, I really thank you for the info and appreciate your depth of understanding. Do any of the books on Android Whatever discuss this? I am happy with posting here, but I have to wonder if something is available to read thru that might fill in the gaps that I have not yet thought of?

User avatar
adafruit_support_rick
 
Posts: 35092
Joined: Tue Mar 15, 2011 11:42 am

Re: Which touch screen?

Post by adafruit_support_rick »

Don't know if any books discuss this type of thing. It's kind of situational. You just have to know what pins your particular shields use. We can help you out with that.

User avatar
NX
 
Posts: 9
Joined: Wed Jul 15, 2015 7:31 pm

Re: Which touch screen?

Post by NX »

Is the Arduino Zero a direct substitute for Leonardo?

User avatar
Franklin97355
 
Posts: 23910
Joined: Mon Apr 21, 2008 2:33 pm

Re: Which touch screen?

Post by Franklin97355 »

Is the Arduino Zero a direct substitute for Leonardo?
Check that out with Arduino.cc

User avatar
NX
 
Posts: 9
Joined: Wed Jul 15, 2015 7:31 pm

Re: Which touch screen?

Post by NX »

I was there, that's why I am asking here ... looks like it might be. Leonardo is "retired".

Locked
Please be positive and constructive with your questions and comments.

Return to “General Project help”