user47246: I am really new to this Arduino stuff. I can't figure out one of my problems on my own.
I am using this 2.4 TFT display shield on an Arduino Uno. It works fine so far: I have coded a little sketch for it that displays a start button and after tapping that it shows random colors.
Now I would like to connect a circuit with jumper cables that are used as sensors. When I touch one of the jumper cables the light connected will turn on.
The problem I have now is that this specific circuit is using an other Arduino because my first Arduino is already 'full' because the TFT shield is taking up all pins.
How can I resolve my problem? Is it possible to Stack Arduinos? Is it possible to connect those Arduinos somehow? Thanks in advance!

user19409: Ok, your problem seems to be that you have run out of pins. Currently you are using an Arduino Uno. I would go out and buy an Arduino Mega.
Alternatively you could use the analog inputs as digital inputs.
Arduino Uno
Digital I/O Pins    14 (of which 6 provide PWM output)
Flash Memory    32 KB (ATmega328P) of which 0.5 KB used by bootloader
Arduino Mega
Digital I/O Pins    54 (of which 15 provide PWM output)
Flash Memory    256 KB of which 8 KB used by bootloader  

user15180: As I can read your link, the shield is using D2-D8 and A0-A3, leaving some pins unused. So some Arduino pins are still free to use, just the shield is in the way to get connected there.
So there are some possible ways:

brutally solder some wires to the shield unused pins from front side and use that wires to connect where you want (sensors, breadboard, universal PCB, ...)
brutally solder some wires to arduino bottom on unused pins, then continue as mentioned
create intermediate shield (there are many, which allow you connect to arduinou on bottom and stack antother shield on top, draw your wires from there (and maybe even put some circuities on the middle shield, if you want 
(something like this https://www.aliexpress.com/item/UNO-Prototype-DIY-shield-kit-for-Arduino-UNO-Universal-Extend-Board-UM-UNO/32555004112.html or any "arduino universal shield" 

https://www.indiegogo.com/projects/ardushield-most-universal-shield-for-arduino-ever#/ works excelently across arduinos and other shields/breadboards ...
or anything along this lines ... http://shieldlist.org/sunhayato/universal

use pins D10-D13 as they are connected also to ISP header https://www.arduino.cc/en/Tutorial/ArduinoISP and could be connected from there. As they are part of SPI interface 
https://www.arduino.cc/en/Reference/SPI that could be good coise too (if you manage ChipSelect somehow.


As for other part of question - 
It is possible to connect more arduinos, there are so much different ways, that it is hard to write here all - choose one, that would suit you best. (anyway you would need some access to some pins anyway )

47246: <p>I am really new to this Arduino stuff. I can't figure out one of my problems on my own.</p>

<p>I am using this <a href="https://www.hackster.io/calogerus/arduino-uno-2-4-tft-lcd-display-shield-touch-panel-ili9341-576b1b" rel="nofollow noreferrer">2.4 TFT display shield</a> on an Arduino Uno. It works fine so far: I have coded a little sketch for it that displays a start button and after tapping that it shows random colors.</p>

<p>Now I would like to connect a circuit with jumper cables that are used as sensors. When I touch one of the jumper cables the light connected will turn on.</p>

<p>The problem I have now is that this specific circuit is using an other Arduino because my first Arduino is already 'full' because the TFT shield is taking up all pins.</p>

<p>How can I resolve my problem? Is it possible to Stack Arduinos? Is it possible to connect those Arduinos somehow? Thanks in advance!</p>
 19409: <p>Ok, your problem seems to be that you have run out of pins. Currently you are using an Arduino Uno. I would go out and buy an Arduino Mega.</p>

<p>Alternatively you could use the analog inputs as digital inputs.</p>

<p><strong><a href="https://store.arduino.cc/usa/arduino-uno-rev3" rel="nofollow noreferrer">Arduino Uno</a></strong><br>
Digital I/O Pins    <strong>14</strong> (of which 6 provide PWM output)<br>
Flash Memory    32 KB (ATmega328P) of which 0.5 KB used by bootloader</p>

<p><strong><a href="https://store.arduino.cc/arduino-mega-2560-rev3" rel="nofollow noreferrer">Arduino Mega</a></strong><br>
Digital I/O Pins    <strong>54</strong> (of which 15 provide PWM output)<br>
Flash Memory    256 KB of which 8 KB used by bootloader  </p>
 15180: <p>As I can read your link, the shield is using D2-D8 and A0-A3, leaving some pins unused. So some Arduino pins are still free to use, just the shield is in the way to get connected there.</p>

<p>So there are some possible ways:</p>

<ul>
<li>brutally solder some wires to the shield unused pins from front side and use that wires to connect where you want (sensors, breadboard, universal PCB, ...)</li>
<li>brutally solder some wires to arduino bottom on unused pins, then continue as mentioned</li>
<li>create intermediate shield (there are many, which allow you connect to arduinou on bottom and stack antother shield on top, draw your wires from there (and maybe even put some circuities on the middle shield, if you want 
(something like this <a href="https://www.aliexpress.com/item/UNO-Prototype-DIY-shield-kit-for-Arduino-UNO-Universal-Extend-Board-UM-UNO/32555004112.html" rel="nofollow noreferrer">https://www.aliexpress.com/item/UNO-Prototype-DIY-shield-kit-for-Arduino-UNO-Universal-Extend-Board-UM-UNO/32555004112.html</a> or any "arduino universal shield" </li>
</ul>

<p><a href="https://www.indiegogo.com/projects/ardushield-most-universal-shield-for-arduino-ever#/" rel="nofollow noreferrer">https://www.indiegogo.com/projects/ardushield-most-universal-shield-for-arduino-ever#/</a> works excelently across arduinos and other shields/breadboards ...</p>

<p>or anything along this lines ... <a href="http://shieldlist.org/sunhayato/universal" rel="nofollow noreferrer">http://shieldlist.org/sunhayato/universal</a></p>

<ul>
<li>use pins D10-D13 as they are connected also to ISP header <a href="https://www.arduino.cc/en/Tutorial/ArduinoISP" rel="nofollow noreferrer">https://www.arduino.cc/en/Tutorial/ArduinoISP</a> and could be connected from there. As they are part of SPI interface 
<a href="https://www.arduino.cc/en/Reference/SPI" rel="nofollow noreferrer">https://www.arduino.cc/en/Reference/SPI</a> that could be good coise too (if you manage ChipSelect somehow.</li>
</ul>

<hr>

<p>As for other part of question - 
It is possible to connect more arduinos, there are so much different ways, that it is hard to write here all - choose one, that would suit you best. (anyway you would need some access to some pins anyway )</p>
