Member level 2
Hi, I have designed a simple 4 pole touch key using ttp223 and modified it a couple of times. I encountered a problem using the final version of it. most of the time it works fine but sometimes when all the switches are on and I touch the third pole it doesn't respond to touching for 10 seconds and then it is back to normal and sometimes while I press the other poles the third pole has a false detection. the circuit has two parts that are connected to each other with pin headers. the power circuit and the touch key circuit that I attached the schematic and PCB for both of them. for the power, circuit p1 is the pin header for 220 to the 5-volt power supply. in the touch key circuit, p1 to p4 are connected to PCB pads. a light guide is placed over the LEDs and the PCB pad and a 4mm glass is placed on the light guide. D1 to D4 are 1n4148. i also attached a link to the datasheet of ttp223. can anyone tell me what is the problem?