| Part's
List:
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M42SP-5
Unipolar Stepper Motor
(or similar)
ULN2003 IC - stepper motor driver
DB25 Male connector |
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| Technical
Specifications:
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About
this Circuit
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This
is an easy to build stepper motor driver that will
allow you to precisely control a unipolar stepper
motor through your computer's parallel port. With
a stepper motor you can build a lot of interesting
gadgets such as robots, elevator, PCB drilling mill,
camera panning system, automatic fish feeder, etc.
If you have never worked with stepper motors before
you will surely have a lot of fun with this project.
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How
Stepper Motor Works?
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 Stepper
motors are very different from a regular DC motors.
Instead of spinning like DC motors do, stepper
motor steps at a specific resolution for each
pulse. The motor that we are using needs 48 steps
/ pulses just to complete a single revolution!
That should be enough to tell about its precision.
Another advantage of stepper motors is the fact
that their speed of rotation can be achieved almost
instantly even if you change the spinning direction.
Stepper motor consists of a rotor
- the permanent magnet that rotates inside, and
stator - four coils (north, east,
south, west) that are part of the case, and which
don't move. Rotor can be moved
by sequentially applying a pulsed DC voltage to
one or two coils at a time.
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Stepper
Motor Driver
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In
able to move the rotor you will need a driver.
Driver is a circuit that applies a voltage to
any of the four stator coils. Driver can be built
with IC such as ULN2003 (pictured on the circuit
diagram), four darlington transistors or four
power transistors such as 2N3055.
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Stepper
Motor Connections
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 Unipolar
motor should have five or six connections
depending on the model. If the motor has
six connections like the one pictured
above, you have to join pins 1 and 2 (red)
together and connect them to a (+) 12-24V
voltage supply. The remaining pins; a1
(yellow), b1 (black), a2 (orange), b2
(brown) should be connected to a driver
(ULN2003) as shown on the schematic. |
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Stepping
Modes
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There
are several stepping modes that you can use
to drive the stepper motor.
1.
Single Stepping - the simplest mode
turns one coil ON at a time. 48 pulses are needed
to complete one revolution. Each pulse moves
rotor by 7.5 degrees. The
following sequence has to be repeated 12 times
for motor to complete one revolution.
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Pulse |
Coil a1 |
Coil b1 |
Coil a2 |
Coil b2 |
1 |
ON |
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2 |
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ON |
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3 |
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ON |
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4 |
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ON |
2. High Torque Stepping - high
power / precision mode turns ON two coils on
at a time. 48 pulses are needed to complete
one revolution. Each pulse moves rotor by 7.5
degrees. The following
sequence has to be repeated 12 times for motor
to complete one revolution.
|
Pulse |
Coil a1 |
Coil b1 |
Coil a2 |
Coil b2 |
1 |
ON |
ON |
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2 |
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ON |
ON |
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3 |
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ON |
ON |
4 |
ON |
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ON |
3.
Half Stepping - stepping is
doubled and
motor needs 96 pulses to complete one revolution.
Each pulse moves rotor by approximately 3.75
degrees. Notice the mix of single stepping mode
(lighter green) and high torque mode (darker
green).
| Pulse |
Coil
a1 |
Coil
b1 |
Coil
a2 |
Coil
b2 |
1 |
ON |
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2 |
ON |
ON |
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| 3 |
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ON |
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4 |
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ON |
ON |
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5 |
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ON |
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6 |
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ON |
ON |
7 |
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ON |
8 |
ON |
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ON |
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- single stepping mode, normal
strength, quiet |
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- high torque mode, high strength, slightly
louder |
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Stepper
Motor Controller Software
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Build your own LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and "Zero Out" function to make sure the readings are as accurate as possible ... [more] |
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Download Stepper Motor Controller