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    USBHost_t36 doesn't recognize MIDI-keyboard?

    Man, what a timely post for me! I was just thinking of hosting an Alesis V49 piano keyboard Midi controller on a Teensy 4.1, and was wondering about whether power management was going to be an issue, or whether there would be other issues as well. So I'll be following this thread with great...
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    Which hardware improvement(s) to reduce noise on Teensy analog inputs?

    What's always worked for me, if you want the best resolution signal with the least amount of noise on Teensy ADC inputs, especially on high impedance signals (say, over 5K) is to use a unity gain op amp buffer between signal and a Teensy ADC input. This may be more fuss than you want, but it can...
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    Improve ADC Readings Teensy 4

    I've been able to eek out 11 bits resolution on the Teensy 4 using a bit of averaging magic. First, I was hardware sampling a piezo sensor conditioning circuit (which produced full, non-rectified +/- 1.65V signals, using the 3.3V output of the Teensy as the reference) at 14.4kHz, using 4x...
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    Teensyduino 1.50 Released

    Have confirmed with a quick test that the Arduino 1.8.12 and Teensyduino 1.51beta combination works fine for my Teensy 3.2 application on a Raspberry Pi 3B.
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    Teensyduino 1.50 Released

    Will do. Thanks for the fast response.
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    Teensyduino 1.50 Released

    Just tried using V 1.50 of Teensyduino with Arduino 1.8.11 on an old Raspberry Pi Model 3B (not plus), which I use from time for time for testing my Teensy project on. (I compile and develop mostly on Windows). Anyway, I haven't used any Raspberry Pi's in a while and especially not this old box...
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    Low profile arrangement of Teensy + Audio shield?

    Great! I guess I can go ahead and build up one with this arrangement and give it a go. Thanks!
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    Low profile arrangement of Teensy + Audio shield?

    While I know you can stack a Teensy board on top of a Teensy audio shield using double insulated header pins as suggested on the audio shield page of this website, what about using ordinary single insulated header pins, as shown in the following photo? The motivation for wanting to do this is...
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    Asynchronous (poll based) touch sensing

    joshnishikawa: It's been quite a while since I've looked at or used this code. I was going to use it for a project that got put on the back-burner. A couple of points: (1) Past lines 112-113 of said header file, I have some "update" comments where I was learning things, the last of which is...
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    tip for faster capacitive touch reads on teensy 3.6/3.5

    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 particular flags being set/cleared that indicates the scan(s) are finished. These latter tests can...
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    Teensy 4.0 Release

    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 ahead and put in an order. Thanks for the tip!
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    Teensy 4.0 Release

    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 conventional (aka larger) circuit boards okay, but soldering to these tiny boards is more than I want...
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    Asynchronous (poll based) touch sensing

    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. First, here's the new touch manager class. Included in this class is a fix that gets rid of...
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    Why the delay in touchRead()?

    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 sure fire way.) This post was the key...
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    teensy 3.2 touchRead() range ?

    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 touch circuitry is being overloaded by that long a cable. Perhaps it has way too much capacitance...
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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: int touchRead(uint8_t pin) { uint32_t ch; if (pin >= NUM_DIGITAL_PINS) return 0; ch = pin2tsi[pin]...
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    Asynchronous (poll based) touch sensing

    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 inexpensive way to put in "buttons".
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    Asynchronous (poll based) touch sensing

    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 micro-seconds. I was just surprised nobody had addressed having a non-blocking way of reading the...
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    Asynchronous (poll based) touch sensing

    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 that here, since the point was to show how to handle asynchronous sensing on multiple pins w/o dma or...
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    Asynchronous (poll based) touch sensing

    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 the Teensy LC and 3.6 devices do. For the former, apparently the...
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    Asynchronous (poll based) touch sensing

    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 port mux for each pin you want), start a scan which scans all enabled pins, check for that scan...
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    Asynchronous (poll based) touch sensing

    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 low level code, each call to touchStartRead() appears to reset the touch sensing and configures...
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    Arduino Serial Plotter 2.0 (update)

    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, you can send commands to your program (I like to use simple characters) to change modes, tweak...
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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 to complete in roughly 100 uSecs). However, a call to touchRead() can take milliseconds, if not...
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    Recommendation for piezo buffer op-amp

    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 AC signal centered at Vcc/2, and a commercial drum trigger / sequencer module? I doubt the...
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    Recommendation for piezo buffer op-amp

    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 negative swings to BE part of the envelope.
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    Recommendation for piezo buffer op-amp

    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 clamping "looser". Bryan
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    Recommendation for piezo buffer op-amp

    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 of the ADC pins on the teensy, regardless of what...
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    Recommendation for piezo buffer op-amp

    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 op amp has a higher slew rate than the MCP604 mentioned above, if that matters to you. Depends...
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    Noise and grounding issues with piezo analog input with Teensy 3.2

    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.
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    Noise and grounding issues with piezo analog input with Teensy 3.2

    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 high accuracy, but the useful low end range of my signal is in the 100 mV region, so having noise...
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    Noise and grounding issues with piezo analog input with Teensy 3.2

    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 conversion rate. In my case, I was using a 1M load across the piezo, which is certainly much greater...
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    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. Basically, in quiescent mode (no tapping on box with piezo attached), and after a reboot, I see 30-40 mV...
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