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  1. If you just want to use poll-based touch sensing,...

    If you just want to use poll-based touch sensing, there is a way to do it without any "blocking" calls and without interrupts -- all it involves is first starting touch scans and then polling for...
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    I hadn't really looked that closely at the Teensy...

    I hadn't really looked that closely at the Teensy 4 image, and yes, I see the components on the board are a lot further away from the through holes than they were on previous teensy's, so I went...
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    Are there plans to provide a SKU for the Teensy 4...

    Are there plans to provide a SKU for the Teensy 4 with header pins already soldered on, like the older products, such as "Teensy 3.2/pins"? If so, any estimated schedule for these? I can solder...
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    Okay, then. I've refined the asynchronous touch...

    Okay, then. I've refined the asynchronous touch class code, and added another class to boot that manages the "state" of the touch pads: NotBeingTouched, RisingEdge, FallingEdge, and BeingTouched.
    ...
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    I think I found a solution, if not answer. It was...

    I think I found a solution, if not answer. It was actually mentioned in these forums (I never seem to find stuff using the searching mechanism. Old-fashioned, pains-taking manual browsing the only...
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    Just a quick thought. The NXP touch documents...

    Just a quick thought. The NXP touch documents recommend no more than 300 mm (a foot) of lead wire/trace from the chip to the sensor. Your long 1.5 meter cable is way over that limit. Perhaps the...
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    Why the delay in touchRead()?

    Was wondering: Why is a 10 microsecond delay used in the function touchRead() in the touch.c file of the Teensy library?

    The code snippet below from touch.c shows what I'm talking about:


    ...
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    The Teensy touch support is indeed cool. Having a...

    The Teensy touch support is indeed cool. Having a lot of fun with it. Don't know if I'm going to use it in my current project, but it's good to investigate the possibilities. Seems like an...
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    The main goal was to get rid of overhead in the...

    The main goal was to get rid of overhead in the main loop. The touch reads can take milliseconds, which was way too much, since the main loop in my current project has a timing constraint of 100...
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    1) I specifically am not using interrupts in the...

    1) I specifically am not using interrupts in the code above. Indeed that was a key part of the design.


    2) Yes, a person could easily add support for button press and release logic. I didn't do...
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    Async Touch Manager class

    Okay, so I've figured out how to do asynchronous touch sensing of multiple pins, without DMA or interrupts. I learned that the Teensy 3.1/3.2 devices have a different touch sensing architecture than...
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    Figured out a way to do what I wanted. Indeed it...

    Figured out a way to do what I wanted. Indeed it seems the idea with the Teensy touch sensors is to enable the pins you'd like to read, all at once, using the TSIO_PEN register, (and also set up the...
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    Well, I've discovered one major flaw with this...

    Well, I've discovered one major flaw with this code: You can only use one touch sensor at a time. You can't start the reading of, say two sensors, and then wait for either to complete. Looking at the...
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    One feature that's sorely missing from the...

    One feature that's sorely missing from the Arduino serial plotter window is the ability to accept serial input from the keyboard. Why would this be nice? So while you are viewing a plot at runtime,...
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    Asynchronous (poll based) touch sensing

    Recently I've had the desire to add touch sensing to a project involving a Teensy 3.2 (or 3.6) but need the touch reads to be non-blocking due to timing constraints (each call to the main loop needs...
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    Are you now rectifying the signal somehow? The...

    Are you now rectifying the signal somehow? The circuit I showed you does not do that. As far as the AC signal "not being compatible with piezo/switch pads" I'm not sure what you mean. Do you mean the...
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    It depends how sophisticated you want to be. I...

    It depends how sophisticated you want to be. I know most piezo trigger circuits you'll see on the web just toss the negative swing information away. I consider the distinction between positive and...
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    You're welcome. As I understand it, your...

    You're welcome.



    As I understand it, your BAT 85s are Schottky's so their clamping voltage is tighter than the 1N4148s I had in mind, so that means you need a higher resistance to make the...
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    Simple diode compression circuit for piezo

    If you power your op-amp with 3.3V, perhaps straight from Teensy's 3.3V pin -- well some supply filtering as suggested would be good -- you won't have to worry about having voltages outside of range...
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    I'm currently working on a project where I use...

    I'm currently working on a project where I use TLV277x op amps to buffer piezos. I used these amps because I had them on hand. I power them with a 3.3V single side supply and seems to work okay. This...
  21. Yes, I'm aware of such things. Was trying to keep...

    Yes, I'm aware of such things. Was trying to keep the circuitry simple. I wasn't aware till yesterday of the need for low impedance sources on the Teensy analog input pins.

    Thanks for the reply.
  22. Yes, I have thought of these things, especially...

    Yes, I have thought of these things, especially after finding out the input impedance on the analog input pins is only 5K. I don't want to complicate the circuitry if I don't have to. I don't need...
  23. Thanks for the reply. Yes, I discovered...

    Thanks for the reply.

    Yes, I discovered yesterday after reading the reference manual for the MK20DX256VHL7 that anything over 5K source impedance could cause problems unless you set the right...
  24. Noise and grounding issues with piezo analog input with Teensy 3.2

    I've been exploring piezo triggering with the Teensy 3.2 board (yes, yet another piezo project), and am seeing strange behavior with noise on the analog signal line and/or grounding issues....
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