Increase sensitivity - TTP223 capacitive touch sensor

[lilyyyw]

Hi, I am Lily. I would like to learn about how to increase the sensitivity for my TTP223 capacitive touch sensor. It seems difficult to find the tutorials or videos for this.

For my project, the touch sensor need to be able to detect the user’s palm from a distance around 20mm through the 2-4mm plastic housing. In this case, the touch sensor should be sensitive enough rather than only working when touching it. Does anyone have any recommendations? Like any advice on coding tutorials I can have a look or any other touch sensor is more suitable for my project.

(Sorry to ask such a simple question. I am really new to the Arduino.)
Thanks in advnce:D Really apprieciate any help.

[Wawa]

The TTP223 calibrates AFAIK for max sensitivity for the connected sensor and ground area every time on bootup.

All you can do is to enlarge sensor area to the size of what's near (your hand), but that might practically be too big for your case. And have maximum ground plane for the rest of the case.
Ground plane is particularly important if your project runs on battery power (no ground connection to a computer or supply).
Leo..

[lilyyyw]

@Wawa

All you can do is to enlarge sensor area to the size of what's near (your hand), but that might practically be too big for your case. And have maximum ground plane for the rest of the case.
Ground plane is particularly important if your project runs on battery power (no ground connection to a computer or supply).

Thanks for reaching out!

1. If possible, I'd like to learn more about the enlarged sensor area. Does it mean I can extend it with any wire or sheet metal, in order to increase the sensitivity?
2. In terms of the size, I can do maximum 30X30mm if this works.
3. My project is using the 12v external power supply (using the power splitter, one goes to my 12v led, one goes to the arduino uno)

Thank you so much for your help.

[Wawa]

You can extend the touch area with any conductive material.
Bare copper circuit board, tinfoil, or even fruit.

The whole idea of a capacitive sensor is to not touch the metal,
but have some sort of isolator (plastic, glass, etc) in between.
I guess there are limits in size, where mains hum or RF pickup becomes a problem.
Just try for yourself. Experimenting is what Arduinos are made for.
Leo..

[TomGeorge]

Hi, @lilyyyw

@lilyyyw

For my project, the touch sensor need to be able to detect the user’s palm from a distance around 20mm through the 2-4mm plastic housing.

You are describing that you need a sensor that detects the presence of a hand, not touch that the TTP233 is designed for.

You may be better of using an ultrasonic unit to detect the presence of your hand infront of the panel.
OR
An IR device such as;

Tom....

[lilyyyw]

@TomGeorge

You may be better of using an ultrasonic unit to detect the presence of your hand infront of the panel.
OR
An IR device such as;

Thanks for reaching out Tom.
For my project, I want my touch sensor HIGH when less than around 20mm and LOW when more than 20mm. Will it still work in this case? Thank you.

[TomGeorge]

Hi,
Yes it will, all you need to know if the hand is in range or not, and set a variable HIGH or LOW.

Tom....

[lilyyyw]

@Wawa

You can extend the touch area with any conductive material.
Bare copper circuit board, tinfoil, or even fruit.

The whole idea of a capacitive sensor is to not touch the metal,
but have some sort of isolator (plastic, glass, etc) in between.
I guess there are limits in size, where mains hum or RF pickup becomes a problem.

Sure, I will give it a try by extending the touch area. Hopelly it still works when having isolator inbetween.
Thank you so much Leo. You helped a lot.

[lilyyyw]

@TomGeorge

Yes it will, all you need to know if the hand is in range or not, and set a variable HIGH or LOW.

Thank you so much. Maybe I can try the IR device if extending the touch sensor with conductive material won't work.
Really appreciate your help Tom :）