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PSoC 5, 3 & 1 MCU

AnSi_331471
New Contributor II

I am trying to make a measurement unit for Resistor and Capacitor value. How to measure the value using PSOC3? And display the measurement value in LCD.

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1 Solution
odissey1
Honored Contributor II

AnSi,

I believe that capsense technique is useful for measuring capacitances in pF range. I am not sure if it will be useful up to 10nF.

/odissey1

View solution in original post

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11 Replies
AlanH_86
Employee

To measure the resistance you can use one of the analog to digital converters in the chip.  There are a bunch of example programs built into PSoC Creator showing these exact measurements.

As to how to display on the LCD it depends heavily on which display you are talking about.

As to the capacitance.  It depends heavily on the range of the capacitance you are trying to measure.  If it is within the range of the CapSense block you can use that.  There are bunches of example projects with CapSense.  If it is above the range then you have a much more difficult problem to solve.

I suppose to really answer you question you are going to need to give us more specifics about what your system problems and constraints are.

Alan

odissey1
Honored Contributor II

aansi,

please check these threads and attached application note for possible solutions.

How to measure small capacitors by switching ouput Pin’s drive mode + Timing measurement?

Real capacitor measurement on CY8CKIT-145

/odissey1

AnSi_331471
New Contributor II

Thank you for immediate response. for the above query I want to add few more data as you ask me.

1. Resistance value to measure is 1ohms to 10ohms with sensitivity of 2ohms

2. Capacitance value to measure is 1.2nF to 7.2nF with 1nF sensitivity.

I have made the schematic for resistor measurement with your idea of voltage divider technique V o u t = V i n ∗ R 2 R 1 + R 2 where R2 is known value for me.

How to setup for capacitor measurement? can you suggest me the calculation and schematic.

Thank you

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odissey1
Honored Contributor II

AnSi,

For precision low-ohms resistor measurement you can try PSoC3/5 RTD component. Please read this App Note

https://www.cypress.com/documentation/application-notes/an70698-psoc-3-psoc-4-and-psoc-5lp-temperatu...

/odissey1

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AnSi_331471
New Contributor II

HI, BoTa_264741

     I got to know about the resistor measurement. Capacitor measurement is still not working. I used Cap sense but not showing correct result. I want to measure 2nF to 7.2nF.

Regards

AK

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odissey1
Honored Contributor II

AnSi,

I believe that capsense technique is useful for measuring capacitances in pF range. I am not sure if it will be useful up to 10nF.

/odissey1

View solution in original post

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AnSi_331471
New Contributor II

hi BoTa,

     I did the same way. Now I read sensor raw data. how do i convert the raw value to capacitor value.? is there any calculation formula?

Thank you'

AK

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odissey1
Honored Contributor II

AnSi,

I am not sure what you are asking about. Do you want to convert capsense raw counts into capacitor value?

/odissey1

AnSi_331471
New Contributor II

Yes, I want to convert the value. Not getting the value. raw data is reading.

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BragadeeshV
Moderator
Moderator

Hi AnSi_331471​,

Yes, we have a raw count equation that helps you to back calculate capacitance from raw counts.

Please refer the following thread.

PSoC5LP Get Seneor Capasitance API

Regards,

Bragadeesh

Regards,
Bragadeesh
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