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PSoC 5, 3 & 1

TiMi_264191
New Contributor II

I found a forum post that indicates one can increase the sensitivity of CapSense to detect a finger inside a glove.

   

How would a developer detect (for example) a felt pad or a voltage biased metal probe moved into "contact" with a CapSense button or slider?  What approach would you take to experiment with this concept using the -001 DVK?

   

Thanks and regards

   

Tim Miner

Tim Miner
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11 Replies
Bob_Marlowe
Expert II

There is the possibility of using a "Tuner" for the buttons and you can monitor the changes of the readings to get a feeling if the changes are sufficent for a safe button detection. Have a look into the datasheet for the CapSense CSD and search for "Tuner".

   

 

   

Bob

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TiMi_264191
New Contributor II

Thank you. Will work on that some today. regards Tim

Tim Miner
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ETRO_SSN583
Esteemed Contributor

"voltage biased metal probe moved into "contact" with a CapSense button or slider?"

   

 

   

First instinct when I read this is if biased probe shares a common ground, and it exhibits, relative

   

to PSOC leakage of a pin configed as HiZ, looks like a v source, simply detect it as a logic

   

level present or absent. May have to be scaled, or offset, but simple interface is all it needs.

   

If Vprobe has a wide range use A/D to establish threshold. Or a comparator.

   

 

   

If ground is not shared, then treatment as an isolated ground, you have to examine common mode

   

problem, which also can be handled if not a crazy CM enviroment, like KV........but there are easy

   

approaches to this as well.

   

 

   

Of course you have additional considerations, noise, drift, offsets, but those are pretty much standard

   

analog issues.

   

 

   

How accurate is the bias, what is its Z, drift, noise......?

   

 

   

Regards, Dana.

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TiMi_264191
New Contributor II

Hi Dana,

   

Your reply on this one is pretty dense... as in I don't understand it all. It does give me hope though.

   

I just got my -030 board working and do not yet have a -031 Kit. For some reason, I thought the -030 board had the I2C connections for the EzI2C CapSense Tuner on board... if it did, I would be experimenting already with the CapSense slider and buttons on the -030 board.

   

I want to embed a slider into/onto a plastic piece and detect the position of a pseudo finger on another plastic part that is snuggled up with the first. I don't want them scraping each other, I just want one detecting the other. The pseudo finger is the felt pad or biased probe I refered to. No high voltages or anything. Think of it as a non-Human Interface Device... haha.

   

A related question is: Do you know if anyone has used an inner PCB layer for the Capsense buttons and sliders and the board material as the overlay?

Tim Miner
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ETRO_SSN583
Esteemed Contributor

This does sound like a capactitive or optical approach in which the finger becomes a sliding shutter.

   

 

   

In so far as inner layers used in C sense, I have never seen any posts or ap notes discussing that.

   

 

   

Regards, Dana.

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Bob_Marlowe
Expert II

I'm afraid you'll need a miniprog 3 to use the CapSense tuner on a -030 board, although I didn't try that yet. The I²C is not connected through the Fx2 - bridge.

   

 

   

Bob

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TiMi_264191
New Contributor II

Hi Dana,

   

I have a mini prog3 and a -001 board as well. Can I use the Tuner with that stuff?

   

What I saw on a -031 video was (using the -001 board with -031 kit) the miniprog3 in the tuner mode and plugged into a header on the -031 adaptor board. So, I still have to wait for the -031 kit right?  OR is there a tuner connection on the -001 board?  I will start looking but I think I misunderstand and got too excited.

   

I've got to sit down and try to understand the CapSense CSD component datasheet now.

   

Tim

Tim Miner
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ETRO_SSN583
Esteemed Contributor

The Miniprog 3 has a dual function, a programmer/debugger and an I2C

   

bridge for the tuner and other. I looked at schematic of Miniprog 3 and it

   

does not bring out I2C to 10 pin (on processor module), and there is no

   

5 pin on main board (Miniprog does bring out I2C to its 5 pin). So I think

   

you need the additional adapter boards.

   

 

   

That being said, might be possible to cobble the Miniprog 5 pin connector via proto block

   

and get it hooked up to function, I have not had the time to confirm if that can be

   

done, take a look at schematics of P Module and -001 to see if you can accomplish

   

that.

   

 

   

Regards, Dana.

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Bob_Marlowe
Expert II

Here is a thread where a community member has solved that problem. Mybe you'll get yours right when you follow the hints...

   

 

   

Bob

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ETRO_SSN583
Esteemed Contributor

This ap note covers the -001 and using the tuner, attached.

   

 

   

Regards, Dana.

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TiMi_264191
New Contributor II

Dana and Bob,

   

Thanks you both for the help.

   

Bob, I do not see the link to the thread yet. But it sure sounds helpful.

   

Dana, Your link is similar to the section in the CSD component data sheet starting on page 28 "Tuner GUI User Guide. I am sure I will be using them both.

   

So, just to clarify... the Tuner GUI is something the Creator IDE launches. It gets the data about my designs CSD component via a I2C slave component (EzI2C) that I include in my design. I also have to physically connect 2 pins from that I2C slave to

   

the SDA(T) and SCL(K) pins on the miniprog3 dongle. That dongle uses its USB ( and an on-board I2C master) connection to the PC to provide the Tuner GUI with 'streaming' data that it then displays and uses to Tune my design (Auto) or give me access to results (constants) that I can include in my design myself (Manual).

   

Yes?

   

I do think I saw something in the CSD component data sheet where if you enable tuning, it instantiates the EzI2C component for you and then tells you to go into it to set a parameter. BUT my head is still trying to wrap around the convolutions.

   

I will try to get unconfused soon. Anyway, thanks again for all the help.

   

Tim

Tim Miner
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