Heroway serial screen FAQ: capacitive touch

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This section covers capacitive touch issues: drift and insensitive touch caused by static or power ripple (stand on the earthed ground and hold the metal frame - improvement indicates static; a clean separate supply fixing it indicates MCU power interference): (1) add a Y capacitor, e.g. a 2KV 103 capacitor between the +5V ground and the protective earth of 220/110V mains; (2) insert a common-mode choke between VCC and GND, two windings in series regardless of polarity; (3) add a 220 uH inductor in series with the VCC line, or parallel large and small capacitors; (4) for surge interference from other loads use a 100 uH inductor plus 16V 1000uF capacitor, and replace the 0R frame-to-screen resistor with a 2KV 103 capacitor; gap between cover glass/acrylic and the sensor causes insensitive clicks (laminate fully, tempered glass beats acrylic, thinner is better, and tune the sensitivity).