Pcb capacitive sensor

[otuzsubat]

Hi. i need a pcb type capacitive sensor, which will detect any object on it. I am planning to put it on a pcb, then i will put a 10mm glass on the sensor. It must have adjustable sensitivity. Do you know such a sensor.
**broken link removed**]

 

[eklikeroomys]

You can try using a Filter type circuit. When you come close to the circuit, the capacitance of the circuit changes, and thereby the amplitude of an AC signal passing through the circuit changes. You can rectify this signal and use a voltage comparator to determine if it is toggled or not.

 

[jpanhalt]

Here are two links that may be useful:

http://ww1.microchip.com/downloads/en/AppNotes/01375a.pdf
Projects - Dexterous Manipulation Laboratory

In the second link, scan down to Fig. 3.1.3. NASA/Goddard did a lot of work on capacitance detectors for object avoidance, like when exploring the inside of a rocket engine. That work was published in the public domain, so it can be duplicated. Unfortunately, all of the links I had have gone bad and direct to pages that charge to download. I have attached a report that is only 23 KB. The appendix to the report has lots of good information, but is 3.2 MB, so I didn't upload it. You may want to just search on "capaciflector," which is simply a capacitance detector with an additional electrode that reflects/focuses the detection field. I built a couple of versions , and they do work. Here is a cross-section of one detector and the circuit I built:



John

 

[electronicsbasecom]

i just used Microchip mTouch CSM module and i detected finger press through 10mm glass easily.

if you know how to work with microcontrollers than read this topic

https://www.edaboard.com/threads/245851/#post1051938

and at the bottom of that topic you have liks to complete project with source code in C language that you can download..

Good luck in your project development and feel free to ask if you have any questions

 

[siongboon]

Yes, such sensor is available.

This circuit uses QT100 and is able to detect touch through glass
**broken link removed**

You can increase the sensitive by changing the capacitor Cs.
Higher Cs will make the sensor more sensitive.
The circuit can detect when your finger is near the sensor.
Very sensitive.

Hi. i need a pcb type capacitive sensor, which will detect any object on it. I am planning to put it on a pcb, then i will put a 10mm glass on the sensor. It must have adjustable sensitivity. Do you know such a sensor.