This tutorial demonstrates how to control bi-polar stepper motors on a Raspberry Pi in Python using a DRV-8825 stepper motor driver. Notes, schematics, code, updates and other resources are available on my website: www.rototron.in...
comparing your explanation and knowledge compared to tons of india tech guy....it cannot be compared in any way....fulll explanation in all aspects..thanx for that
You do a fantastic job of presenting a complex (probably not for you) system. I am an old school mainframe programmer from the 60's-70's. I have two Raspberry Pi's and am programming the hell out of them but you put my playing to shame. Kudos and love your tutorials
Agreed. I learned more about stepper motors and how to control them in this tutorial than anywhere else I looked. After mocking up something on a breadboard and getting it working, I transferred that onto a Raspberry Pi HAT breadboard and it works fantastically
This is an exceptionally excellent tutorial and class. Thank you so much for sharing your knowledge! I'm currently studying stepper motors for usage on precision peristaltic pumps for prototyping a dosing machine. Thank you once more, you're great!
thank you for this work as it did open some aspects of the PI to me, but also covered the method of telling what your stepper driver is doing, so that you can set it ahead of time to around what you need with a lot less fidgeting to get the output for a given motor, (if you know the values it is supposed to receive) to get it set up, the first time. Again thank you.
Hi I starting my small project with stepper motor and I found your solution for controlling it , I am very impressive of you work , The last part using hardware_PWM is great and doing exactly what I need , but one thing :) how to change the direction instead slowing down. I mean the motor will do one ramp on CW direction then another ramp but on CCW direction .
I'm not sure I understand your question. It has been a long time since I used this library, but you should be able to set the direction using pi.write(DIR, 0) or pi.write(DIR, 1).
This is an awesome video. I have been struggling to use a RPI with a serial port HAT to control bipolar stepper motors using old Shopbot control boards and the Shopbot DOS program through an emulator. It works, but the DOS emulation is not powerful enough to run the motors at full speed. It looks like I need to try a DRV-8825 and learn some Python. Thank you!
Hi, firstly this code (including the micro-steps) all worked great for me. I was just wondering if you could further customise the code to allow manual control of the motor (ie typing a positive or negative value into terminal so motor moves clockwise or anti-clockwise a number of steps) and then controlling multiple motors at once? I'd love to run up to 4 motors and I think this is such a solid base setup for code but looking for some help! Thanks :)
I am wanting to use a Raspberry Pi Pico to run a NEMA 34 stepper motor. IMO using a raspberry pi to run a stepper motor is like driving an 18 wheeler to the store to buy milk and eggs. Granted the Pico was released after this video was made. The problem with the Arduino is the frequency is not high enough to run the NEMA 34 at maximum speed. I am going to experiment with the DRV-8825 Controller since it takes up less Real Estate then a standard Stepper Controller.
I followed this to the letter looking for answers why my stepper motor does not turn smoothly, but is very erratic and jumps in both directions. I've been hoping to find out why I'm having this problem.
This is the best tutorial I have seen. However, could you tell me please how the code becomes if we want adjust the speed of a stepper motor by selecting a specific frequency (example :1010 Hz) using hardware_PWM(18, frequency, duty cycle) and then rotate the motor with a specific angle at that speed ?
To accurately control both frequency and steps, I think you would need to use the PiGPIO _generate_ramp()_ method. I’m not sure if it supports the hardware PWM which would afford more precise frequency control. It might automatically switch to hardware if you use GPIO 18. You would have to hook up a scope to determine if you are getting the correct frequency. You could also ask Joan the creator of PiGPIO. She is very good about responding to questions and she might have additional recommendations.
Great Video, I need to move my stepper motor as a function of sine wave lets say for time in incrementing from 0to 100s y=amplitude*sin(2*pi*frequency*t) so displacement of stepper motor should as per change in y could you help me in that
Hello, I am a software engineer looking to make a cnc machine and I'm a bit confused on some of the electrical engineering aspects of this. Could you explain how I could use a capacitor to ensure that my power supply is safe if I am soldering directly and not using a breadboard? Thanks!
The capacitor is to protect the DRV8825 board from LC voltage spikes. You should put a minimum 47 µF electrolytic capacitor rated for at least 50 V across motor power (VMOT) and ground somewhere close to the DRV8825 board. Please see the Pololu Robotics DRB8825 product page for more details: www.pololu.com/product/2133
First example which actually made my motor run using Python on the Raspberry, a lot of other tuts did not make my motor run. I used Livecode too, which also works, but the graphic interface interferes with the motor strangely. With the GPIO i got errors like: please use GPIO.setmode(GPIO.BCM) which i did, so i don't understand this error, also it also run only CW and not CCW, could see the motor react on it and stalled.
First off thank you for such a clear and detailed explanation of this process. I have been successful in performing your steps. My application has a need for switch controlled movement with a pair of momentary buttons. ex. button 1 press moves ccw until released and a press of button 2 moves cw until released. Any guidance for this capability would be appreciated. I don't want to have to change over to an Arduino solution if i don't have to. My application is for a Z-axis bed for a laser engraver that will be controlled separately. Again thanks for your videos..
My example with the toggle switch would work. You just need to change the main loop to something like: dc = 128 if pi.read(SWITCH1) == 0: pi.write(DIR, 0) elif pi.read(SWITCH2) == 0: pi.write(DIR, 1) else: dc = 0 pi.set_PWM_dutycycle(STEP, dc) sleep(.1)
HELP PLEASE. Yes I love the presentation as everyone else has mentioned. However, I'm at a loss here... I've hooked everything us as seen, and my motor wont move at all. There's no resistance either, just as though the power is off completely... So It's a sl42sth34-1334a stepper motor I 'borrowed' from my Flyingbear 3d printer. The stepper driver is a generic pololu ripped from a ramps board (i tried two, same issue) When measuring the v.ref pot, I'm getting a range from 0.00v to 0.20v (on both drivers) The driver is green, with a small square chip. The text on the chip is: 4988ET A1640 990L Tested motor with the LED coil test, both coils are generating power, and lighting the led. The cap i'm using is 24v 100uF The External PSU is 12v If you have any suggestions, please let me know. Thank you :)
Hello, I am trying to do the same with a raspberry pi zero, a nema 17 stepper motor and an L9110S controller but without success, the motor vibrates and spins randomly. can you help me ?
Hello, what would be the ideal voltage of drv 8825 driver if usinf a nema stepper with 1.5A current at 12V. I want to make a button presser to press button of 1.6N in a full step mode but its skipping a step while pressing a button thus not presing it all the time
did you ever find a way to use the touch screen for stepper motors? I want to do the same but with up and down arrow to lower and raise rpm rate and maybe another set of arrows with time setting then a simple play/stop button to start and stop the program
i wish there would be a implementation for gpio in ugs or bcnc or something, so you can actually use your rpi directly without having to connect a extral driver board. it's just a matter of programming, but nope.... non existing, or at least, not to be found.
Hello, very good tutorial, hepled me a lot! I just have one problem, I wanted to build a robot and use the stepper motor for the movement but your tutorial show the stepper driver still connected to a power supply, which is impossible for a robot. How can I bypass this problem?
A 12V battery should work similarly to a 12V bench power supply assuming the battery can provide the necessary current. Please note that stepper motors draw power continuously regardless of motion which may not be optimal for a battery powered application.
Great video with clear explanation. I have one question. If we are going to create 3d printer setup can we use any six GPIO pins for step and direction(2 pins for each driver)..
@@rdagger Hello sir, I Will try with the code which you shared for single motor. If i need to run 3 motors with 3d printer setup, do we have any reference code available. Appreciate your great help on this:)
I haven't tried it, but I think you should take a look at PyCNC. Otherwise it would be difficult to achieve the precise timing required for 3d printing. github.com/Nikolay-Kha/PyCNC
We are looking to control two steppers with a raspberry pi and have them open and close doors on a building. Is it possible to use a single dial of some sort to control the opening and closing of the doors. As a matter of fact, the doors only have to open and close about 15-20 degrees . So, we want to be able to turn the dial and move both steppers (one to the right and one to the left) at the same time. Can this be done with raspberry pi? Can this be done by incorporating an arduino with the pi? We really need to use the pi
Yes, it could be done. The Raspberry Pi doesn’t have an analog input so you would need an analog to digital converter to connect the pot. I have a video on connecting ADC’s: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-wJgyszOSoQU.html Potentiometers often have jitter so you would need code to smooth out the rotation and prevent unwanted movement. Depending on the size and weight of the door, you might need an industrial stepper motor, driver and power supply. I don't think the 2A driver used in the video would work. There are more pitfalls as you scale up and you could be dealing with potentially dangerous voltages. I would use end-stops to limit the range of motion. I would also add sensors to detect if something or someone is blocking the path of the door. You could also go with a closed-loop system to accurately track the position of the door. Please check your local building and fire codes to ensure you comply with all safety ordinances.
You should know that electrolytic capacitors doesn't provide reliable protection against HF spikes and oscillations because of their parasitic inductance due to design nuances. So the right way is to use a low capacitance (about 100nF) ceramic or film capacitors in parallel to electrolytic and as near as possible to device itself.
The driver breakout board already provides low-ESR ceramic bypass capacitors. Both Pololu and the DRV8255 datasheet recommend adding an electrolytic bulk capacitor as shown in the video.
One other question... What is supplying power to the 3.3V rail on the breadboard. Is it coming from the raspberry pi? The breadboard I purchased came with a generic power supply circuit board with pins aligned to supply 3.3V and ground to the outer rails of the breadboard. Could that be used with this type of setup or is it obsolete since we're using the raspberry pi? Thanks again
The 3.3 V power is coming from the Pi. At 5:54 I connect a 3.3 V pin from the Pi to supply logic power to breadboard's power rails. You can use your breadboard's power supply assuming it is 3.3 V. However, you still need to connect a ground from the Pi to the breadboard's ground rails to establish a common ground because voltage is relative. I would not use the breadboard's power supply because it adds another potential failure point, and it doesn't provide any benefit other than saving 1 wire.
