I have a device X (talking toy), which has a jack of two wires for an external button. That is, I can short the two wires and device X accepts it as a press of a button.
Now, I want to use device X for it's function, but replace mechanical button with a capacitive sensor. I have options, but lets assume it's a cheap TTP223 module, with GND, VCC and IO pins, operating at 2 to 5.5 V. When I checked with 3.3 V, it gave about 2.64 V logical "1" on IO pin when touched. At 5 V, gives 3.8 V for "1".
The device X's jack gives about 5 V on it's button jack and even 800 Ohm resistor seems to trigger it. About 210 uA current flows through the button when shorted.
As I see it, the sensor will have it's own power supply (voltage is part of the question).
The main question is, what is the best way to convert logical "1" into "press of the button"? Preferably, without the need for multiple voltage levels. What could be good "relay" for the task?