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Overview
Many of the previous Raspberry Pi projects I had been working on were based on fairly simple GPIO logic to turn things on and off. Today I wanted a little more of a challenge so I started working to control a stepper motor from my Raspberry Pi using Java. Fortunately I had previously obtained one of John Jay's Stepper Motor Breakout Board kits which includes all the necessary components (including the stepper motor) to get started.
The kit includes:
- 1 @ printed circuit board
- 1 @ ULN2803 8 Channel Darlington Driver IC (Adafruit)
- 1 @ 18 pin DIP socket (Amazon)
- 8 @ green LEDs
- 1 @ Jumper and Jumper header
- 1 @ resistor array/network
- 1 @ capacitor
- 1 @ 26 pin PCB mount female header (not pictured)
- 1 @ peel-and-stick on rubber bumper (not pictured)
- 1 @ 28BYJ-48 5 VDC stepper motor (Amazon | Adafruit)
This kit is very easy to assemble and very reasonably priced.
It is available now on eBay. << Click here to see John Jay's eBay listings >>
It is available now on eBay. << Click here to see John Jay's eBay listings >>
Assembly
Please visit John's website for further instructions and photos on assembly:
<< http://mypishop.com/Stepper.html >>
<< http://mypishop.com/Stepper.html >>
Shopping List
- 1 @ Raspberry Pi (see this page for more Raspberry Pi related supplies)
- 1 @ John Jay's Stepper Motor Breakout Board (kit) (includes stepper motor)
Logic
The stepper motor is controlled by pulsing the GPIO pins from LOW to HIGH states in a sequence that causes the motor to spin. Each time a GPIO pin state is HIGH an electromagnet is engaged inside the stepper motor to cause a rotational force on the center rotor. With the proper sequence and timing you achieve motor rotation.
Here is a fantastic article with photos and illustrations to help learn more about stepper motors and stepping techniquest:
http://www.lirtex.com/robotics/stepper-motor-controller-circuit/
For more detail: Raspberry Pi – Stepper Motor Control & Breakout Board
