Same pins. Different jobs.
Recall the LED circuit.
- The short leg, −, goes to GND.
- The long leg, +, goes to a pin through a resistor.
What does that mean for the pin?
OUTPUT — When set HIGH, the Uno pin supplies approximately 5V: the “+” for our LED circuit.
Recall the touch sensor.
We had three connections:
- VCC (voltage supply COLLECTOR) or VIN (Voltage INPUT).
- GND — the power return, −.
- Signal — the sensor’s answer.
What does that mean for the pin?
INPUT — Input is NOT gnd !!!
It does NOT act as the ground connection
and does NOT close the sensor’s power circuit.