Touchscreen Paint Example

The LCD has a 2.8" 4-wire resistive touch screen glued onto it. You can use this for detecing finger-presses, stylus', etc. You'll need 4 pins to talk to the touch panel but we reuse some of the pins for the TFT LCD! This is because the resistance of the panel is high enough that it doesn't interfere with the digital input/output and we can query the panel in between TFT accesses, when the pins are not being used.

Visit our github repository and click on the Downloads button in the top right corner to download a zip of the library and examples. Uncompress the folder and rename it TouchScreen make sure that inside that folder is the cpp and .h files. Then copy it to your arduinosketchfolder/libraries folder. See our tutorial for more details.

We connect the 4 pins as follows:

  • Y+ is connected to Analog 1
  • Y- is connected to Digital 7
  • X+ is connected to Digital 6
  • X- is connected to Analog 2

Now start up the tftpaint_shield example in the TFTLCD library. The right hand side will have 'color boxes' you can press to select which color you want to draw with. If you press the area to the left where the screen ends, it will erase the screen.

The touch screen is made of a thin glass sheet, and its very fragile - a small crack or break will make the entire touch screen unusable. Don't drop or roughly handle the TFT and be especially careful of the corners and edges. When pressing on the touchscreen, sometimes people can use the tip of their fingers, or a fingernail. If you don't find the touchscreen responds well to your fingers, you can use a rounded stylus which will certainly work. Do not press harder and harder until the screen cracks!
Last updated on May 04, 2015 Published on Nov 30, 2012