CAPSENSE™ & MagSense Forum Discussions

Hi,

I am Ananth From Vortex Engineering Pvt Ltd Chennai. We are planning to select the processor with following Spec

Architecture :64 bit

Flash memory : Greater than 1MB

Operating Frequency : Minimum 500 MHz

Should support with ML and other applications too. we are searching the correct MCU/MPU for this.

Kindly support for this as soon as possible

e-mail - ananth.ravi@vortexindia.co.in

Thanks and regards

Ananth Ravi

Hi,

I am Ananth From Vortex Engineering Pvt Ltd Chennai. We are planning to select the processor with following Spec

Architecture :64 bit

Flash memory : Greater than 1MB

Operating Frequency : Minimum 500 MHz

Should support with ML and other applications too. we are searching the correct MCU/MPU for this.

Kindly support for this as soon as possible

e-mail - ananth.ravi@vortexindia.co.in

Thanks and regards

Ananth Ravi

Hello,

According to AN85951, the recommended value of series resistance placed on the CapSense sensor is 560Ω.

However, the CY8CKIT-149 uses a 2KΩ series resistor.

I looked at the schematics of some evaluation kits.
CY8CKIT-041 (PSoC4000S): 560Ω
CY8CKIT-145 (PSoC4000S): 560Ω
CY8CKIT-042-BLE (PSoC4200): 560Ω
CY8CKIT-149 (PSoC4100S Plus): 2KΩ

Why is only CY8CKIT-149 using a 2KΩ resistor?
Is the choice of 2KΩ resistors due to a special reason for this board?
Or does the PSoC4S Plus series have different recommended resistance values?

Best Regards,

Naoaki Morimoto

I’m trying to work if the CapSense p/n CY8CMBR3110-SX2I. I was able to programming the device with the configuration below.

/* Project: C:\WIP\Projects\ARM_Devices\SVueCommon\Westlock\Touch Buttons EZ-Click Project\TouchButtonsRev01\TouchButtonsRev01.cprj
* Generated: 3/1/2021 09:17:55 -05:00 */
const unsigned char CY8CMBR3110-SX2I_configuration[128] = {
0xEEu, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u,
0xCCu, 0xFCu, 0x00u, 0x00u, 0x7Fu, 0x80u, 0x80u, 0x80u,
0x7Fu, 0x80u, 0x80u, 0x80u, 0x7Fu, 0x7Fu, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x03u, 0x00u, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x80u,
0x05u, 0x00u, 0x00u, 0x02u, 0x00u, 0x02u, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x1Eu, 0x00u,
0x00u, 0x00u, 0x1Eu, 0x00u, 0x00u, 0x00u, 0x01u, 0x01u,
0x01u, 0xFFu, 0xFFu, 0xFFu, 0xFFu, 0xFFu, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x02u, 0x03u, 0x01u, 0x5Bu,
0x00u, 0x37u, 0x06u, 0x00u, 0x00u, 0x0Au, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u,
0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x00u, 0x9Eu, 0x10u
};

But, I’m having problem to get the buttons status. I’m reading 2bytes starting in the register 0xAA and those bytes are always zero.

Is there any other register I need to write to enable the chip to work? I had looked in some examples and I couldn’t find what I’m missing.

Do you have any code example using 5 buttons that I can use to check if I’m missing anything?

Hello,

I have a question regarding the buzzer output of the CY8CMBR3108. The datasheet at https://www.cypress.com/file/46236/download does not specify whether the buzzer output is push-pull or open drain. Figure 8 in the datasheet appears to suggest that the output signal is open drain. However, when I measure the voltage on the buzzer pin without anything connected to it, it is high. 

Please note that I configured the CY8CMBR3108 to have a buzzer output signal on that pin.

Any help would be appreciated.

Thank you

Hi all,

You might want to read this older post   https://community.cypress.com/t5/PSoC-4-MCU/Analysing-a-mutual-capacitance-sensor-s-signal-disparity/m-p/48477#M3641

I am trying to fully understand the behaviour of electric fields in mutual capacitive technologies  like CSX. I have run a series of tests with different overlay thicknesses under 0.5 mm (0 to 20mil with 2mil increments) to see how Capsense would fluctuate when a floating conductive object and when a grounded object would touch it.

I have used a copper plane the size of my CSX touchpad, glued to a plastic handle, and weighted to firmly press on the overlay.

Image 1: Hardware setup to test effects of copper plane on CSX touchpads with an overlay thickness lower than 0.5mm

I have recorded data for multiple overlay thicknesses and plotted (image below) the mean raw count reading of all the sensing elements of the touch pad, so I can compare the overall effect of overlay thickness on raw counts

Image 2:  Mean Raw counts for 0 to 20 mil overlay thicknesses

This graph shows how the capacitance increasing effect of the floating copper plane (reduced rawcounts at the middle of plot) is damped as the overlay thickens. Same goes with the capacitance decreasing effect of the plane once it is grounded. This makes sense as the copper plane is further away from the touchpad, its effect is lowered, whether it is grounded or not.

My question

What I do not understand however is that I  have not been able to trigger signal disparity with the copper plane, even when the tests were run without overlay (0 mil thickness on the plot). I would have expected the grounded copper plane (right section of the graph) to increase the capacitance, therefore lowering the rawcount compared to normal at 0 mil, but it actually shows the highest rawcount increase at 0 mil overlay thickness.

Basically, I would have expected a turnaround like the red line above at very low overlay thicknesses, but I have seen a line like the yellow one in my results.. How can this be explained?

I must mention that a finger does result in the capacitance increase, however (red line), when I press on the touchpad without overlay. I just do not understand why it is not the case with the grounded copper plane.

Thank you!!

For a research project we would like to use a coaxial cable as a type of sensor. The cable will be embedded in a semi malleable substrate. Upon a given force the crossection of the cable should take on a more elliptical shape and therefore change the capacitance. By monitoring the capacitance we would like to count the number of force pulses exerted onto the surface of the substrate. 

The solution should be very robust and simple. Since the number of impulses is much more important than the exact amplitude, the setup does not need to be overly precise. 

The elephant in the room however is that the baseline capacitance of the cable will be far greater than the difference in capacitance as result of the exterted force. 

Is there any "box ready" solution to the problem? 

I have a board that's been in production for several years that uses CY8C20180 (SO16 package). Now I see that CY8C20180 seems to be obsolete. Is there a pin-compatible replacement for this part? If not, is there a functionally compatible part?