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    New Stepper Motor Library

    I did not want to wait for the Teensy 4 port to be done properly, and did not want to read any datasheets, so I made a hacky port (https://github.com/bondus/TeensyStep) to Teensy 4 using ChibiOS timers (https://github.com/greiman/ChRt) It might hang, crash and burn, and be very slow. I have...
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    Read Endless Potentiometer

    Fascinating knob! Very clever. Using arctan will not give the right angles in this case, it works for that resolver since it has sinus waves. The solution for this knob is actually very simple: :) if(v0 < 50%) angle = 360 - v1 *180 else angle = v1 * 180 v0 and v1 are assumed to be...
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    Teensy 4.0 and step stipcks hookup.

    Quite embarrassing. :rolleyes: I am the idiot again sending 12V into the poor Teensys 3.3V, and the drivers IO power pin. A crappy cable carrying 12V on my prototype board had the plastic insulation melted and it sometimes contacted the 3.3V line! I really need to improve my prototype building...
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    Teensy 4.0 and step stipcks hookup.

    That was me too. My pile of dead boards is quite respectable. Makes a grown man cry. It seems like the powering sequence is the issue here. The motor power supply has to be turned on and stable before you turn on the logic power. The TMC chips are quite fragile too, powered on in the wrong...
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    Teensy 4.0 and step stipcks hookup.

    Did some further research while waiting for new Teensies to ship. From https://learn.watterott.com/silentstepstick/faq/: And indeed the TMC is messing with VIO, the supplied 3.3V logic voltage, when powered up. Not enough to kill an Arduino UNO, but enough to kill a Teensy 4.0.
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    Teensy 4.0 and step stipcks hookup.

    Explaining your problems makes you think :) After some measurements it looks like the damned chip has internal pullups to some internally generated 5V. When motor power is supplied to the chip it will pull-up some IO pins to 5V, even if the digital power supply is 3.3V. Bastards! I could add...
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    Teensy 4.0 and step stipcks hookup.

    Another Teensy project, another pile of dead teensies :( I hooked up a stepstick (TMC2208) by the book to a Teensy 4.0. EN, STEP and DIR are directly connected to Teensy pins, VCC_IO (as TMC calls it) to 3.3V from the Teensy 3.3V supply, and VMOT to a 12V supply. All GNDs are common. And a...
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    [posted] Quadruped walking robot

    I have been struggling hard to make it keep some kind of dynamic balance, ie take speed into account. But I fail miserably all the time :( I think one of the problems is that the hobby servos have a massive slop in the gearboxes. At a normal stance you can wiggle the legs +-1cm sideways, all is...
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    [posted] Quadruped walking robot

    The leg hinges are in PP, polypropylene, perfect plastic for hinges. And 3D printable, at least for simple items like this. There is still a bit of flex in non-wanted angles when the legs are at extreme sideways positions, but the hip servos tends to give up in those situations. The small flex...
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    [posted] Quadruped walking robot

    I forgot to mention that never ever connect a PWM pin from the Teensy directly to a servo. It works fine until the cables on the servos short, intermittently, sends 6V to the teensy and fries it. Believe me, I have 5 fried Teensies. It works with a 330ohm resistor in series. The proper solution...
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    [posted] Quadruped walking robot

    I wanted to learn modern machine learning by building a small walking robot and have it controlled by a neural network. I will get to that, eventually. That's the primary reason I chose the Teensy 4 over other platforms, it has the computing power to run some decently sized neural networks in...
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    T4 killing board

    That umbilical blob is a LiPo pack watcher. It beeps loudly when a cell is too low. I already broke one pack due to discharging it too much, my speciality is breaking hardware :)
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    T4 killing board

    Got some videos of it walking/climbing/stumbling around. https://youtu.be/a22FzKibE3c I could write something about it and post in the Blog section.
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    T4 killing board

    It turns out it was the servos sending back their supply voltage to the PWM pins! I was totally sure that one of my boards broke with no servos attached. I was wrong. The (very low quality) cables to the Tower Pro servos had worn out over time and were shorting at the servo end. For this last...
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    T4 killing board

    Two more dead Teensies, only one left :(. At least I am supporting the project :) The last one died when I connected the USB port while the Teensy was powered on, running on battery. I use SPI so the LED is constantly flickering, when I inserted the USB port it went black and the board was...
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    T4 killing board

    The 2nd teensy with broken USB was "reprogrammed" using the 15s button hold you mention, it is blinking. When in programming mode or running that blink program there is no reaction from the USB host when plugged in, even if I reconnect VUSB to VIN to power from USB. It is quite strange that the...
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    T4 killing board

    I built this little board to control a little robot with a T4. It's mainly a puzzle of various pre-made modules. It has one big switching voltage regulator to provide power to 12 tiny servos, 5.5V. That voltage (should) never get in contact with the Teensy. It has one small switching voltage...
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