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Thread: TeensyStep issue - Driver not working

  1. #1
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    TeensyStep issue - Driver not working

    I have prototyped stepper motors running at precise speeds on an Arduino Micro and just found out about TeensyStep -- my mind is blown!

    I have 2x 400 step motors, and 2 different drivers that work with the Arduino setup, but one of the drivers doesn't work with the Teensy.

    I suspect this is because I need to step up the logic from 3.3 to 5V. Since the full build of the project involves 10-12 motors/drivers at semi-high speeds, with hidden circuitry, what would be a clean and simple way to get my non-working driver to work?

    This is assuming I am correct as to why it is not working. Please advise if I'm overlooking other considerations.

    Links:
    Motor 1 400 Step
    Motor 2 400 Step
    Big Easy Driver Manual & Specs @ 3.3V
    Non-Working TB6600 Driver
    3rd A4988 Driver I haven't tested (but have available)

  2. #2
    Senior Member+ Theremingenieur's Avatar
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    Normally, the data sheet of the motor driver should tell you the required logic levels for correct operation. Reading and studying technical information will save you time and prevent wild guessing. If level shifters are needed, i.e. because the motor driver would require at least 3.5V for logic high (which is common 70% of 5V logic), you might use 74hct125 or 74hct245 ICs to solve the problem.

  3. #3
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    Thanks for the reply. Ooops, link to datasheet is fixed.
    Here's the datasheet (link) for it -- it says the 3.3-24v Control Voltage so should work.

    Here are my tests results:
    Teensy 3.2 + BigEasy Driver + TeensyStep Library = GOOD
    Teensy 3.2 + BigEasy Driver + Manual stepping (my old code) = GOOD
    Teensy 3.2 + TB6600 Driver + Either Code = NOT WORKING
    Arduino Micro + (either Driver) + Manual Code or AccelStepper Code = GOOD

    Question 1: Any ideas why my preferred driver isn't working?

    Thanks for the recos on chips. I realized the best option is to use a driver that accepts 3.3V.

    Question 2: Does anyone have a reco for a good quality Stepper driver that accepts 3.3/5V pulses and 1.68A/Phase?

  4. #4
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    Question 1: Any ideas why my preferred driver isn't working?
    The TB6600 like most of the "larger" drivers has optocoupled inputs for the control signals. Driving them with 3.3V is very borderline. They state a 3.3V compatibility on the website but not in the datasheet?
    As Theremingenieur already explained you should really use a level shifter if using a 3.3V system with optocoupled inputs. Here a link to a thread with more information: https://forum.pjrc.com/threads/50148...hlight=stepper

    Question 2: Does anyone have a reco for a good quality Stepper driver that accepts 3.3/5V pulses and 1.68A/Phase?
    The standard "good" drivers I know are all optocoupled. For >=NEMA17 I like the Leadshines e.g. the DM556 which has a fantastic performance. For <= NEMA17 I use the DRV8825(more current) or the A4988. I never use steppers at their rated current since they get very hot and loud. Depending on the torque requirements you can usually operate them at half current or even less. If the 3.3V operation is important for you I'd give your A4988 @0.9A a try.

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    Thanks again for all your input. Just curious if you think you might have a testable library to play with

    At the moment i'm considering changing my creative direction to accommodate library abilities. I made it really far with manually driving everything but don't think its that much further ahead than what libraries offer. ATM I am back to reworking things with either AccelStepper or TeensyStep.

  6. #6
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    I assume you refer to the ability to change the motor speed on the fly? As usual, it turns out to take more time to do things as anticipated in the beginning. However, the rotational modes already work, currently I'm integrating the move modes to the new controller. So, if you are interested in testing the rotational mode with changeable speed I can provide a test version (probably) tomorrow.

  7. #7
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    Correct, looking to take a new constant speed and accel/decel to it from whatever speed is currently running. Take your time, I understand.

    I likely will be focusing on it after Xmas thru Jan 3rd. I'll be locking my approaches within that time but do plan to revisit the entire piece for future iterations and would love to switch to TeensyStep should you choose to adjust the library later on.

    I had some luck doing this manually (with the help on forums), but ultimately am thinking that working within library abilities will be a simpler and allow to focus on fabrication for a bit.

    How might the "rotational mode w changeable speed" work?

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