Arduino communicating with Touch sensors

Hi all!

I am considering to use a Qprox QT60486 matrix sensor for controlling 48 keys. This is a really cool chip that allows you to make any kind of surface into a 48-key keyboard.

I have been reading the specs (u can download them from and u can use UART communication, where you have a Rx ant a TX Pin.

My question is: How can I use this to connect my matrix to the arduino Board in order to give it the position on the matrix that has been activated?

Can I just connect the Tx pin of the chip to an arduino digital pin, and recieve a byte from the Qprox and then decode by software which is the position that is being sent?

Or am I just not understanding at all the communication protocol and asking silly questions?

Any help or pointer to useful information will be more than welcome !



Hej Cristina,

the issue you are referring to has been answered in the forum a couple of times. You could refer to:

However, the answer is simple. Arduino - the ATMEGA8 chip we are using - has only one hardware UART. It is linked to the pins 0 and 1. If you use those pins to send/receive data from other devices than the computer, then you will disable the possibility of communicating back to you PC or Mac. For standalone installations this is very useful, since the serial port/USB is not needed.

On the other hand, if you are interested in keeping the communication to the computer going, Mr. Mellis is developing a library that will allow to declare any pin as serial I/O. In that case it will be possible to do exactly what you are asking for: to communicate to the computer and, at the same time, read/write from/to a serial peripheral.

Anyway, you could of course try to control de serial communication coding it yourself. In that case I could recommend you to take a look to the latest revision of the avr libraries by Pascal Stang, whose work is very much used in Arduino. It is actually one of his libraries we are modifying right now to make it fit in the system.

Hasta pronto,


PS. where have you been? We missed you in the forum for almost two months

ciao cristina

you can use the spi interface on that chip. I've used the spi interface on a number of other qprox devices with no probs. I have some code that might work with that

the only drawback is that it needs 4 pins

i'll try to publish the example in the next few days.


Hi David and Masssimo!

Thanx guys for the information. I am studying now both the UART and the SPI options and will see which one to use. Although 4 pins is indeed expensive, as you say Massimo.

About the forum, sorry for having kinda disapeared, my boss has kept me until now doing PR work on the studio, exploration trips and writing reports about the explorations.... A pain in the #%$ !!!!

Anyway, starting this week I am finally allowed to start my prototyping phase!!!

So expect me being much more active from now on. Ah! David, I haven't forgotten about the code on the LED circle from Madrid, just let me warm up a few days and once I re-test it to be sure it's OK I will be sending it, and hopefully more stuff on what I will be doing!

Talk to u guys soon!



I've posted my code

the spi function i'm sure works for your chip

careful when designing the sensing electrodes.. it's always a nightmare with capacitive sensors. and remember every time you change the electrode in any way turn off power so that the sensor will reconfigure.


by the way: mario found a touch sensor solution without additional hardware: