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Type: Posts; User: Vadim Lopatin

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    Another theremin sensor design for Teensy 4. ...

    Another theremin sensor design for Teensy 4.

    I've changed plan once again - completely different theremin sensor schematic.
    Phase shift sensor seems worse than classic heterodyne.

    Teensy 4...
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    Project status update: Received ordered phase...

    Project status update:
    Received ordered phase shift sensor PCBs from pcbway.
    Going to solder and test.
    DMA code is not ready yet, but direct polling of FlexPWM capture registers is enough for...
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    Theremin GUI on previous (abandoned project)...

    Theremin GUI on previous (abandoned project) version of teensy theremin - on Teensy 3.6

    18420

    Teensy 3.6 performance is too low. E.g. 60MHz F_BUS gives too low precision for reference...
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    Ordered PCB: 18404 18405 18406 KiCAD...

    Ordered PCB:
    18404

    18405

    18406

    KiCAD project is available on GitHub
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    Pipe Monster v4 digital theremin antenna and...

    Pipe Monster v4 digital theremin antenna and sensors mounting.

    Made of 20mm and 32mm PPL pipes and fittings.
    Antenna sizes and distance between antennas - like in Etherwave.
    32mm pipe pieces...
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    Thank you for sharing of useful link! Modern SMD...

    Thank you for sharing of useful link!
    Modern SMD 1-2 gate logic ICs are nice for compact PCBs.
    It doesn't make sense to use RF connectors for inductor and antenna connection.
    Anyway, only 1 wire...
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    I didn't try to model parasitic capacitance of...

    I didn't try to model parasitic capacitance of PCB.

    It makes sense to add ground plane below reference frequency buffer cirquit.
    Trace from antenna/inductor output should be thin and w/o ground...
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    Based on additional experiments with LTSpice...

    Based on additional experiments with LTSpice models, schematic of Phase Shift Sensor board is updated.

    Better ICs are going to be used as buffers and ESD protection.
    Big input capacitance of ICs...
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    PhaseShift library development progress: For...

    PhaseShift library development progress:
    For now, pin2 is hardcoded as reference signal generator (channel A of FlexPWM4 submodule 2), and pin3 (channel B of the same submodule) as input of shifted...
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    BTW, at least in Teensy4 there is hardware...

    BTW, at least in Teensy4 there is hardware encoders support, with debouncing and automatic step count.
    Did someone try to use it?
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    To simplify soldering of sensor prototype, I've...

    To simplify soldering of sensor prototype, I've created KiCAD project.

    Changes comparing to LTSpice model:

    * Power input is +5V. 3.3V regulator added to minimize noise via power line.
    *...
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    Phase shift theremin sensor on Teensy 4 Trying...

    Phase shift theremin sensor on Teensy 4

    Trying to build as simple theremin sensor as possible.

    In theremin sensor, we have to measure antenna capacitance with VERY high accuracy.
    Typical...
  13. Teensy can measure time interval with timer...

    Teensy can measure time interval with timer resolution which equals to F_BUS. It's 150MHz on Teensy 4.0 with 600MHz clock, 200MHz when overclocked to 800MHz, 250MHz when overclocked to 1GHz (with...
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    Simulation of phase shift detection approach -...

    Simulation of phase shift detection approach - with bigger Q and C values corresponding to hand distances 1cm, 11cm, 21cm, .. Bottom line is 1cm. Blue line - 21cm, green line - 31cm, gray - 41cm,...
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    Thank you for feedback. When can digital...

    Thank you for feedback.
    When can digital theremin be called theremin?
    Quadrant heterodyne design is really close to analog theremins.
    In approach I'm proposing for pitch sensor, if fine grained...
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    Teensy 4.0 based Digital Theremin

    Hello!

    I'm working on my hobby digital theremin project.

    Theremin is musical instrument controlled by distance between player's hand and antennas.

    In theremin, there are two antennas - one...
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