View Full Version : Touch sensing: sliders, rotary, etc

11-01-2012, 08:02 PM
So I'm a complete novice with all things regarding touch sensing but I'm curious to know if the Teensy 3.0 will be capable of supporting touch control scenarios similar to the control types supported by Freescale's TSS (http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=TSS). Obviously the software here is far different from Teensyduino; what I'm interested is if the Kinetis hardware has anything special inside it to handle the input on non-button touch controls, such as linear sliders, rotary controls, and keypads. Is this sort of control handling something that a simple library could unlock, or is it a matter of doing all the processing using touchRead in software?

This is very, very cool, so I won't be disappointed if it's not easily done :)

11-01-2012, 08:31 PM
It certainly is possible to implement sliders, rotary wheels and such. It's all "just" a matter of math, with multiple touchRead() values collected over time, and reading the millis() time. Really, what's needed is a library that calls touchRead() and millis() and does the math to give you results specific to the type of controls you've connected.

My limited understanding of Freescale's software is it implements the low-level driver (roughly the same as touchRead), it provides that library to do the math over time, and it has some sort of GUI program for configuring the controls for the library. I honestly haven't looked at Freescale TSS stuff much. It had a complex, restrictive-looking license, so I started from scratch with the datasheet to give Teensy a "clean" implementation.

12-27-2012, 02:26 AM
This is my first project with the teensy 3: http://njhurst.com/blog/01356576041 I made a simple slider. I'm not sure if there is a more clever way of doing it. I have a fair amount of noise being detected. I wonder if there is a way to make a gray code like sensor that could use only a few sensors but still have close electrodes?

To the OP, I think to do rotary you just have three or four electrodes in a circle and look at the order in which they are triggered.

10-29-2013, 02:17 AM
Did anyone experimented more wit it? I'm really interested in adding a touch slider to my teensy.

05-19-2014, 08:50 PM
Dear all,

Did any of you already try to hack the phidget linear touch to work with Arduino of Teensy? I could not find anything on the internet but somebody has probably tried. Or is there another similar sensor that can be directly accessed through SPI, I2C or serial? I had good hopes for the Sjoni sensor but they still have problems getting their sensor stable (http://www.sjoni.nl/wip.html). The good thing is that they are quite honest about it.

Hope somebody has a good tip.

Best, Hans.

06-24-2015, 01:07 AM
I know it's been quite a while since this was posted but I was wondering if there were any more details. I've tried implementing a slider similar to njh's example but the values are way too random. it seems like they *might* trend towards something usable with a LOT of filtering but certainly nothing even close to the example values. Anyone have any alternative layouts etc. to try?