I am doing a mini project, and I need the following:
Connect 6 capacitive sensors TTP223 to the same input.
I have to get one of these two solutions:
get a single TTP223 to have a larger pulsed area (I have no idea how to do it).
Connect them all to the same D7 input (I have no more free inputs), but when I connect them they don't respond. I understand that it must be because when you have one it sends the 3v voltage and it must cause a problem with the other sensors. I have tried to put a M7 diode, but no matter how I put it... it doesn't work.
You have a typical problem, not enough pins. Look at the PCF8574, it uses I2C and will give you 8 additional I/O. Since you only have one pin, you can remove one and add it to the port expander along with your six TTP223s. If the I2C pins are used as I2C you have it made, if not you can move those two items to the port expander. Some code changes and you are off and running.
If you want to connect the totem-pole output sensor with a Wired-OR, use one schottky diode for each sensor.
The connection the anode to Arduino D7 and the output of the TTP223 to the cathode.
Must be sure to use TTP223 in active-low mode.
And Arduino D7 requires pull-up.