FDC1004EVM: Sensing Distance

Janine Lin

Part Number: FDC1004EVM
Other Parts Discussed in Thread: FDC1004, FDC2214

Dear T.I. Team

In the datasheet under Capacitive Proximity Sensing Using the FDC1004, it says that the proximity sensing range is depend upon the sensor area size. As shown in the data below.

In the FDC1004 evm, what is its longest sensing distance and how to know its sensing value in the Sensing Solution EVM GUI software? The sensor area size of the FDC1004 evm is 13 x 13mm,

i think its sensing range is over 15 cm. Please, i need your help. How to get 15 cm proximity sensing range by using FDC1004 evm?

over 5 years ago

0 Bala Ravi over 5 years ago

TI__Expert 6625 points

Hi Janine,
We've got your request. Our response may be delayed due to holiday season, we will get back to you as soon as possible.

Best Regards,
Bala Ravi

0 Clancy Soehren over 5 years ago in reply to Bala Ravi

TI__Mastermind 23810 points

I responded to this request through private message.

0 Janine Lin over 5 years ago in reply to Clancy Soehren

Expert 2190 points

I used sensor electrode at the size of 2.5 cm(circular) but the sensing range(proximity sensing) not even reach to 1 cm. The table shown above is not accurate. This FDC1004 is good for liquid level sensing but not for proximity sensing.

0 Clancy Soehren over 5 years ago in reply to Janine Lin

TI__Mastermind 23810 points

The FDC2214 is better for proximity sensing; however, you should be able to replicate the results if you follow the procedure outlined in the app note. Note that the target does need to be grounded. The shielding could also impact the sensing distance.

0 Janine Lin over 5 years ago in reply to Clancy Soehren

Expert 2190 points

Thank you Clancy.

Which one is good for remote liquid level sensing, FDC1004 or FDC2214?

0 Clancy Soehren over 5 years ago in reply to Janine Lin

TI__Mastermind 23810 points

They both can be used for remote liquid level sensing. The trade-off is this:

FDC1004 has a shield output, which can be used to reduce external interference. For instance, if there is a possibility for a hand to approach from the opposite side of the sensor, then the FDC1004 might be a better fit.

The FDC2214 has better sensitivity and a wider input capacitance range. It is also less susceptible to EMI.

0 Janine Lin over 5 years ago in reply to Clancy Soehren

Expert 2190 points

Thank you Clancy. Does FDC1004 is good for detecting paper or plastic?

0 Clancy Soehren over 5 years ago in reply to Janine Lin

TI__Mastermind 23810 points

Janine,

If the material gives enough of a dielectric change, then it is possible for capacitive sensing to be used. You will need to look into the dielectric constants of the particular materials you need to measure.

I believe that paper and plastic do not have even close to the same dielectric change as from air to water, so it might not be feasible. To even have a chance, the FDC2214 will probably need to be used.

0 Janine Lin over 5 years ago in reply to Clancy Soehren

Expert 2190 points

Dear Clancy,

For proximity sensing, as the target approaching the sensor plate, Delta value changed (increases). But when my target is at steady state, delta value decreases.

I am confused, how to determine the sensing range. Is it when the target is approaching the sensor ( 1 or 2 seconds) or the target is at steady state?

According to Bala, delta noise floor must be 10x.

0 Clancy Soehren over 5 years ago in reply to Janine Lin

TI__Mastermind 23810 points

Janine,

You should not see too much change when your target is at steady state. However, there may be slow moving drift due to temperature effects or external effects on the capacitance. Ideally, the response from the target interaction should be an order of magnitude over any drift and noise.

0 Janine Lin over 5 years ago in reply to Clancy Soehren

Expert 2190 points

Thank u Clancy. Got it.

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FDC1004EVM: Sensing Distance