DC motors are used in a wide
variety of applications. They can be used in novelty items and toys such
as train sets right through to more serious applications in industrial
process control and automation. Whatever the application the role of the
humble DC motor can be greatly enhanced by controlling
it’s motion from a
PC compatible computer. Having the “intelligence” of the PC available to
dictate the operation of the motor allows elaborate control systems to be
created with the flexibility of the PC control system. Whatever the DC
motor is “hooked up” to the first step is to bring it under PC control
both in speed and direction. For this purpose we will use a “MotorBee” USB
adaptor board and a small 9v DC motor arranged in a worm drive to increase
Connecting the motor to MotorBee
The DC motor has two connection points. One is invariably
labelled ‘+’ and one ‘–‘. To a certain extent this is fairly meaningless,
as the motor will operate with either polarity of supply. Reversing the
supply simply makes the motor go in the opposite direction. Some
applications only require the motor to go in one direction albeit at
varying speeds and , for this purpose, the MotorBee has 4 independent
motor control outputs. However, in our application, we require the motor
to go in both directions so we will be using two of the MotorBee outputs
for this one motor. We will use outputs 1 and 2 for this and the
connection arrangement is shown below.
Although the MotorBee gets it’s own power directly from it’s
USB connection to the computer, the power to drive the motor is supplied
separately. The 5v available on the USB cable to the MotorBee powers it’s
on-board processor and it’s associated control circuitry. The external
supply to power the motor in our case is a 9v battery. A photo of the
connection arrangement is shown below for clarity...
With these connections made then all we have to do now is
connect the MotorBee to a free USB port of the PC using a standard cable
and we are then ready to run the MotorBee software.
MotorBee is supplied with it’s own control software to
allow beginners to quickly get up and running. The software is called
MotorWay and installation from the supplied disk is straightforward. In
the vast majority of cases all you need to do is click on the “Next”
button on every screen to accept the default installation.
Once installed and running, MotorWay will present you with the following
Although MotorWay offers a range of facilities for creating
your own sequence control system we will focus on the manual controls
needed to get our motor running under PC control. The drop down menu box
on the left of the screen allows us to select “Manual” control.
In the top half of the screen you will see 5 vertical slider
controls. The first four of these are used for DC motor control and the
last one on the right for Servo control. The motor control sliders
correspond, from left to right, to outputs 1 to 4.
Since we are using outputs 1 and 2 we are only concerned with the first
two on the left. Between these two sliders there is a drop down selector
box offering the choice of “single” or “twin”. This is to distinguish the
use of outputs 1 and 2 being used for two un-directional motors or 1
You should select “Single”. When you do this you will see two
new selection options appearing below it offering “Forward” or “Reverse”.
Initially select “Forward”. This will cause the first slider to become
active and the other to be “greyed out” inactive. Moving the slider up and
down will now cause the attached motor to respond by varying it’s forward
speed to match. Selecting the reverse direction switch the active slider
to slider 2 and the motor will respond similarly to this control but in
the reverse direction.