PCF8883

[elyeskhalifa]

Hi,

I am working on a project that consist in detecting the proximity of metallic containers through a plastic layer.

I am interested in the PCF8883 for its low power consumption.

Would it be possible to do that given the following details :

• Detection distance (5 to 10 cm)
• Plastic layer thickness 5 mm

If not is there any other sensor that could do it?

Regards.

[david_diaz]

Hello Elyes,

NXP’s capacitive switches use a patented digital technique (patent from Edisen) to detect a change of capacitance on the device input. In order to use this switch, the following must first be defined:

• Mechanical outline and materials to be used
• The desired switching distance from the sensing plate and
• Application specific optimal approach speed sensitivity

A large distance (several meters) between the sensing plate and the IC is possible.

The circuit has three parameters that influence the switching behavior. Below they are listed in order of their influence:

• Switch sensitivity (CCPCcapacitance between CPC and VSS)
• Calibration of the total capacitance on the sensor input (RCbetween IN and VSS)
• Switching speed (CCLINbetween CLIN and VSS)

I recommend using the PCF8883 evaluation board in order to evaluate the device.

I hope this information helps. Please let me know if you have any further question.

Regards,

David