i recently bought grove piezo sensor and grove GSR sensor and i want to connect them directly to an arduino (without using base shield).
in the GSR sensor there are 4 connection: GND,VCC,TP4,SIG. does anyone knows where to connect the TP4 in the arduino?
i googled it and saw in an arduino forum that i dont have to connect TP4 to anything but there must be a reason why it exist.
the same question i have with the piezo sensor only the piezo sensor has NC connection instead of the TP4 in the GSR sensor.