Stepper Motor Control Made Easy
Control Two Stepper Motors From a Single USB Port
Includes AutoStep Control Software
Stepper motors are one of the most useful devices in the world of control, automation and robotics. They form the most convenient and versatile bridge between a set of motion rules in a controller (computer) and the motion itself. They can be made to move slowly, quickly, in reverse, pause, complete revolutions, partial revolutions and even individual steps of less than a degree of rotation. With this flexibility of movement coupled with an abundance of torque for relatively little power applied, the stepper motor finds many suitable applications.
The downside to stepper motors is that they are not as simple to “drive” (electrically speaking) as simple DC motors, which just need the required volts and amps to do their bit. Stepper motors need a precise sequence of pulses delivered to the correct winding at the correct time in order to perform their required task. It would be nice if all you had to do was specify the number of steps to take , in what direction and at what speed and the stepper motor obliged. This is the function of the StepperBee USB adaptor board.
From the PC these requirements can be specified and “sent” to the StepperBee via USB, which then generates the precise sequence of pulses on the appropriate winding to move the stepper motor accordingly. The StepperBee can accommodate two stepper motors operating completely independently using this technique. For example one stepper motor may be sent off to do 1000 steps clockwise at a rate of 1 step every 100ms followed by 100 steps anti-clockwise at 1 step per minute, whilst at the same time motor 2 can be executing it’s own task which might be to do 100 steps clockwise then anticlockwise in a continuous repeating way at a rate of 1 step/sec. The StepperBee sorts out the two motors pulse requirements and makes sure both motors are supplied with the correct “drive” to perform the specified tasks.
The ability to control two motors with independent tasks in this way opens up many possible application areas for the StepperBee which are not easily available with other stepper motor drives. Popular applications that take advantage of this are with x-y co-ordinate drive systems where one motor controls the X-position and one controls the Y. Specifying the appropriate sequence of tasks can produce some very elaborate positional oriented control systems.
Since the StepperBee also has some digital inputs and outputs available for the users program to make use of, it is then possible for these to be used to control a third or 4th axis (albeit in a more simple way) for applications that could, for example, operate a solenoid on the X-Y positioned device. In this way “pick and place” type applications spring to mind. Similarly the StepperBee has a few digital inputs which are typically used to provide some form of feedback from the controlled device. For example a limit switch may be set at some known point and every so often the device could be made to move there until it “makes” the switch establishing to the computer exactly it’s position (i.e. datum point).
StepperBee comes with it’s own control program “AutoStep” which allows even the complete beginner to quickly get up and running with stepper motor control. It provides both manual and automatic sequence control of any attached stepper motors without the need for any programming knowledge.
Connecting the stepper motors to StepperBee is very simple requiring just the 4 phase wires from each motor and a GND (0v) connection as shown in the diagram supplied. Stepper Bee is compatible with standard 4-phase unipolar stepper motors requiring up to 500mA per phase. For higher current requirements (more powerfull motors) see StepperBee+.
A standard USB lead (not included) is needed to connect the Stepper-Bee to your computer . Stepper motors are not included. Note: The new style stepper bee does not have, and does not require, the heatsinks as shown in the photo. Both styles of stepper bee are functionally identical.
Writing Your Own Programs
If, however, you are already a competent programmer and wish to write your own programs for Stepper-Bee then a DLL (dynamic link library) is provided on the installation disk which greatly simplifies this process. This DLL allows user programs written in a wide range of languages (eg C, C++ and Visual Basic), to have easy access to it's facilities. It provides standard functions which can be called from the library to
- initialise the Stepper-Bee,
- set number of steps,
- step interval(speed),
- set direction,
- read inputs and
- send output bit patterns
without having to get to know the details of USB operation or comms etc... For more detailed information on how to use this DLL and example source code for visual basic please follow this link
Stepper-Bee Visual Basic
Information on programming in C++ is available within the manual, which may be downloaded from the following link.
Compatible with Windows 2000, XP, Vista, Windows 7 and Windows 8
Note: This is not a "Kit of Parts". It is a fully assembled and tested unit.
Note2: Unfortunately, due to changes in the Royal Mail "signed for" service, we are no longer able to deliver to PO Box addresses outside of the UK.
Not for connection to Mains Voltages