mosfet to capacitive swich using one wire

[turbogt16v]

hy peoples.
i have limited knowledge on electronics, so i need your help.
i am making a small project, its a 10w led with a capacitive swich to be implemented in a table lantern.
i am also using arduino to mimic candle burning. its all powerd by 15v 2.5a trans, so i am using buck converter to lover the voltage to 10v, so i can power arduino and led.
i want to make a capacitive swich using mosfet and a metalic plate, but i can't make it power off and on using same plate, i only manage to power it on and off using 2 plates, one for on and one for off.

is there a possibility to make it work using one plate, i will post picture of project.

https://drive.google.com/file/d/1dw7EGOIwWA7j5btHRnm2j_IQQhGCFaj4/view?usp=drivesdk

 

[Harald Kapp]

This will not work as intended. And if you get it working, it will not work reliably.

Since you are using an Arduino anyway, use 2 pins of the Arduino and a library to make the capacitive sensor. Then control on and off in software.
You can also buy off the shelf capacitive sensor modules. Look for "TTP223B Digital Touch Sensor". Then you will need only one pin af the Arduino and you will not need the capacitive sensor library,

 

[turbogt16v]

it works well, but only when i added caps on the end of plate, i have tried arduino capacitive library, but it has a lot of disturbance, a mosfet is better option.

any way thank you for fast response, and glad to see you still on the forum.

 

[Harald Kapp]

it works well,

but in your original post you stated

i can't make it power off and on using same plate,

So what is correct then?

 

[turbogt16v]

i can make it work by splitting the wire connected to the gate and using 2 diodes, and 2 caps, one way to open gate or on, and other way to close it or off, you can see it in the picture i have aded.
i needed a way to work it using only one wire.

 

[Harald Kapp]

Then use the MOSFET as a sensor input to the Arduino and do the state switching (on/off) in software.