Need stepper motor that travels 6 Deg/step.

Discussion in 'The Projects Forum' started by holychachi, Aug 2, 2011.

  1. holychachi

    Thread Starter New Member

    Jul 13, 2010
    Im looking to build a clock with an arduino and stepper motors. Only problem is I can only find motors that turn at 1.8 or 7.5 or 3.6 deg per step.
    So anyone know of a motor that can go 6 deg per step or 60 steps per rev or 'X' deg per step that can add up to 6?
    I know the first thought is going to be to grab an old clock and rip out the innards, 60 steps per revolution there, but I want to start fresh on this.
    Thanks in advance.
  2. THE_RB

    AAC Fanatic!

    Feb 11, 2008
    If you use a microstepping driver (like the LiniStepper; it can do 1800 steps/rev or 3600 steps/rev.

    Both those divide by 60 units per revolution, good for stepper motor clocks. It also has the benefit of a PIC on board so that can be your entire clock brain and motor driver, like this clock;

    Other microstepping stepper drivers will do 800, 1600 or 3200 steps per rev, which you could also use if you can tolerate not getting each minute an exact 60th of a rev.
  3. John P

    AAC Fanatic!

    Oct 14, 2008
    Alternatively, get a 200 step/rev motor and give it a sequence of 3 steps the first second, then 3 steps the second second (!!) then 4 steps the third second, and repeat. After 20 sequences of 3 seconds each (= 1 minute) you'd get (3+3+4) * 20 or 200 steps, i.e. one full revolution. I doubt if the unequal motions per second would be noticeable.
  4. tracecom

    AAC Fanatic!

    Apr 16, 2010
    I am planning a similar project using a PICAXE and three really cheap 7.5° motors: one each for the hours, minutes, and seconds (three dials side by side). I will have code for the PICAXE that can either full step or half step the motors and will use the following 5 second sequence: full step, half step, full step, half step, full step, and then repeat. Thus, the second hand will move 5 times in 5 seconds and cover 30° (7.5 + 3.75 + 7.5 + 3.75 + 7.5). Granted, the steps won't move the hand the same amount each time, but there will be 5 movements in 5 seconds and the hands will point in exactly the right place every five seconds, which is where the numbers will be.