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hello everyone welcome to controllers
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tech I have already made a video on
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stepper motor but that one only shows
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how to rotate the motor regardless of
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the speed angle or the direction today
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in this video I am going to make it a
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bit more interesting this is another
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video on stepper motor and this time we
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will vary the RPM change the direction
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and also step the motor through some
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angles let's start by creating project
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I am using f103 c8 controller let's give
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a name to this project let's set up the
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cube MX part first of all I am enabling
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the external crystal for the clock next
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select the serial wire debug now I am
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setting PA 1 to PA 4 as output these
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pins are connected to the stepper I will
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show you the connection in a while let's
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set the clock now I want the controller
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to run at maximum clock possible here in
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this case 72 megahertz
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note that a PB 2 timer clock is also at
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72 megahertz setting the timer for
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microseconds delay if you don't know
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check the video on the top right
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setup is complete click Save to generate
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this is the connection stepper motor is
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connected via uln 2003 motor driver to
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the f103 controller pin a1 goes to in-1
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a2 2i n 2 and so on motor driver is
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needed because the current consumption
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is stepper is high let's write the code
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first of all I am writing a function to
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create delay in microseconds set the
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counter to zero wait for the counter to
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reach the entered value
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now I am going to write a function for
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the half drive for the motor as shown in
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my website the motor takes 8 steps in
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the half drive first only a is high then
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a and B both are high then only B is
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high then B and C are high and so on
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here a B C and D represents the pins
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connected to the motor
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here only first is hi here first and
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second both are high than only second
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than second and third and so on
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now the motor takes 4,096 steps in half
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drive to complete one revolution eight
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steps in half drive is called a sequence
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this way the motor completes 512
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sequences for one revolution I am
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defining here the number of steps this
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motor takes for one revolution if you
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are using wave drive or full drive then
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steps per revolution would be 2048
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but the sequences would still be 512 as
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the motor now takes 4 steps to complete
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a sequence this here is the function to
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set the RPM for the motor I have tested
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it and found out that maximum rpm for
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this stepper is around 14 although it
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misbehaves at 14 so I wrote here the max
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you can use this function as a delay
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now inside the main function first we
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have to start the timer
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let's see the calculation if I want to
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run the motor at rpm of 14 the delay
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would be 1046 microseconds
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to run at one revolution per minute the
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delay would be fourteen thousand six
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hundred and forty eight microseconds
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as I mentioned 512 sequences are needed
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for one complete revolution
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I am going to write a for loop for these
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512 sequences for each sequence the
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motor is going to take 8 steps making it
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4096 steps let's set the RPM of 5 at
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so there is no error in the code let's
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debug it then select stm32 application
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leave everything default and click OK
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as you can see the motor is rotating as
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expected you can time this video and
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count the RPM this part is exact one
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minute long so it is easier to count it
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the stepper made 5 revolutions as we
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asked it to do let's increase the RPM
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now I am making it 13 flash the code
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again note that the speed has increased
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I am only running this part for 30
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seconds if you want to count
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the motor completed around six and a
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half revolutions in 30 seconds exactly
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what we needed now it's time to write
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the function for the angle the motor
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will rotate by the angle in the
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parameter we can also control the
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direction and rpm like I mentioned there
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are 512 sequences for one revolution
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which means zero point seven zero three
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one two five degrees per sequence we can
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find the angle the number of sequences
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motor needs to complete
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we can also control the direction by
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reversing sequence of the steps in the
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half drive let's test it for the
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Here I am writing 45 degrees first and
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clockwise direction with an RPM of 10
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and it will keep repeating every one
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let's build it and test
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I am steeping through this code to show
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you the angle calculation now when we
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enter the function the angle is 45
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number of sequences come out to be 64
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this is 1/8 of the 512 as 45 is of 360
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let's run it now you can see the result
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yourself the motor rotates for 45
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degrees every 1 second
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let's change the angle to twenty two
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point five degrees and flash the code
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again I will change the RPM to twelve
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as expected the motor now takes 22.5
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degrees in each second this is it guys I
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hope you will make some better use of it
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leave comments in case of any doubt you
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can download the code from the link in
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the description have a nice day
