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Proximity Touch Controller

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gauravkothari23

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Hi all.
I need to make a 4x4 matrix keypad with touch sensor. I initially planned to use MTCH108 as a touch controller. but it has only 8 channel.
can anybody please suggest me what touch controller IC can i use for my 4x4 matrix keypad = 16 keys.
MTCH108 is a standalone IC and does not need a Mcrocontroller. But if needed i can use the same to interface any touch controller.
 

Hi,

If you can use a microcontroller, then you may use about any touch field with the appropriate controller.
Some microcontroller even have built in touch controller.

Just choose the size you like and let the software define the size and position of the keys.

Klaus
 

Hi,

If you can use a microcontroller, then you may use about any touch field with the appropriate controller.
Some microcontroller even have built in touch controller.

Just choose the size you like and let the software define the size and position of the keys.

Klaus

Thanks...
i have came accross some of the touch controller IC with I2C interface with my 8051 controller.
I am planning to use MTCH6102 which has approx 15 channels.
 

Hi...
i have a bit confusion while using MTCH6102.
can i connect the RX(i) pins of MTCH6102 to different pads for making keypad or i have to design it in Gesture form.
for example...
i need to interface 14 touch buttons. so can i connect each button independently to each inputs(RX(i)) or i need to define gestures in X and Y format.
 

as i have connected individual round touch pads to MTCH6102 RX0 to RX9 pin, i am interfacing 10 keys.
can i leave other pins floating or my interfacing concept is wrong.
 

Hi,

You speak about "round" touch pads and about the interfacing....

This let´s me assume you did not read the datasheet.
--> Read the whole datasheet, but especially chapter 6.


Klaus

Added:
If you look for individual touch key ICs, then maybe the AT42Qxxxx series is better suited. Read the datasheets.

Klaus
 

Hi,

You speak about "round" touch pads and about the interfacing....

This let´s me assume you did not read the datasheet.
--> Read the whole datasheet, but especially chapter 6.


Klaus

Added:
If you look for individual touch key ICs, then maybe the AT42Qxxxx series is better suited. Read the datasheets.

Klaus

Yes i agree that MTCH6102 does not support individual touch key, but also AT42Q.... series does not have more than 11 channels and i need upto 14 channels.... i have two applications where i need 10 and 14 buttons to be interfaced.
anyways my question with MTCH6102 is my PCB is in U shape(Sample Image Attached). so how can i design a circuit in such a shape. will it be possible.

- - - Updated - - -

so now my X will be connected to 4 pins of MTCH and y to 4 Pins of MTCH, so now rest of the pins of MTCH can i leave floating.

- - - Updated - - -

as in he chapter 6.2 i have came across one some points
2. Each axis must have the associated channels in
either ascending or descending order.
3. No unconnected channel pins are allowed in the
middle of a layout.

its confusing me... bit difficult for me to understand this para
 

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Last edited:

Hi,

"U" shape?

The MTCH6102 is a touch controller for a rectangle XY matrix. (Matrix = not individual)

You are free to choose how much "X" resolution and how much "Y" resolution channels to choose.
The toatal of X + Y is limited to 15 channels.

The maximum of active sensor areas is 8 channels of X, and 7 channels "Y" giving a total of 8 x 7 = 56 areas.

*******************
The QTouch ar for individual keys with individual shape.
You may use multiple ICs to access more than 11 keys.

Klaus
 

Hi,

"U" shape?

The MTCH6102 is a touch controller for a rectangle XY matrix. (Matrix = not individual)

You are free to choose how much "X" resolution and how much "Y" resolution channels to choose.
The toatal of X + Y is limited to 15 channels.

The maximum of active sensor areas is 8 channels of X, and 7 channels "Y" giving a total of 8 x 7 = 56 areas.

*******************
The QTouch ar for individual keys with individual shape.
You may use multiple ICs to access more than 11 keys.

Klaus

Yes.. even i mean to say the same that MTCH6102 works in matrix form.
but will it work as the attached circuit diagram. Its also matrix design in the U shape PCB
 

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Hi,

Your "U" has
* no true columns (X-coordonates in a matrix) where you can connect one of thw 15 channel lines
* no true rows (Y-coordonates in a matrix) where you can connect one of thw 15 channel lines

--> the numbers in your given picture show "areas" instead of columny and rows.

Klaus
 

Hi,

Your "U" has
* no true columns (X-coordonates in a matrix) where you can connect one of thw 15 channel lines
* no true rows (Y-coordonates in a matrix) where you can connect one of thw 15 channel lines

--> the numbers in your given picture show "areas" instead of columny and rows.

Klaus

new image attached just for an idea.
please refer to and let me know what type of changes have to be made.
red box are the X coordinate which are connected together in top copper
yellow box are the y coordinate which are connected together from bottom copper
and the No. in green are for reference only where i am going to place my keypads NO.
 

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Hi,

In your above picture you don´t show where you decide to connect the sensor lines.
I can´t find how you think it should work.
I can´t see why you can´t use the complete rectangle area.

I can only recommend to follow the datasheet recommendations as close as possible.

Klaus
 

Hi,

In your above picture you don´t show where you decide to connect the sensor lines.
I can´t find how you think it should work.
I can´t see why you can´t use the complete rectangle area.

I can only recommend to follow the datasheet recommendations as close as possible.

Klaus

here is the circuit diagram where white lines shows the sensor line for Y axis placed at bottom copper and red lines on top copper as x axis.

- - - Updated - - -

i cannot use rectangular PCB because the enclosure what we are using is itself in the U type shape
 

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Hi,

I don't know if the (missing) diamonds will cause the circuit to fail.
It seems you have to test it, to see what happens.

Klaus
 

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