started building the main touchscreen interface using the same Arduino UNO R4 WiFi and 2.4 inch TFT display setup that i already used before. instead of jumping into the PC side first i wanted to get the hardware feeling right because if touch detection itself is not reliable then the whole project falls apart. so i first made a simple landscape UI with six app tiles and started testing how every touch was actually getting mapped on the screen.

the biggest issue was touch calibration. the display was rendering everything perfectly but the resistive touch layer was returning different raw values than expected. while mapping p.x and p.y using the map() function and checking each app boundary with the apps[i].x, apps[i].y, bw and bh values i noticed the touch coordinates were not lining up with the actual grid. because of that pressing one app was opening another one and some buttons only responded with extra pressure.

• spent most of the time tuning the MINPRESSURE threshold recalibrating the raw touch range and matching the mapped coordinates with the display rotation until every touch area finally started responding to the correct app.