Engineering Letters

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Design and construction of wireless two stepper motors
control system based PIC microcontroller using RF
module
Min Chit Ko, Kyaw Soe Lwin

Abstract - Stepper motors is the most useable tool applied in
process control, machine tools and robotics. Especially in
robotics and process control, it is necessary to control the
stepper motor from a remote place. The radio frequency
module is basically a PIC microcontroller based wireless
communication system. The control switches are used to
control the direction of stepper motors corresponding angle.
The resolution of motors is 7.5 degree/step. The status of
these switches is transmitted by using RF transmitter and
receiver. The RF modules used in this project are KST (
Tx-01) transmitter and KST (Rx-706) receiver. The four
switches are interfaced to the RF transmitter through the
16F877A PIC microcontroller. The microcontroller
continuously reads the status of the switches, pass data
through the RF transmitter displayed on LCD module and the
transmitter transmits the data. At the receiving end, the RF
receiver receives this data, gives to the microcontroller. The
microcontroller reads the data and after processing, performs
the corresponding action i.e., to rotate the motors clockwise
and anticlockwise. 16x2 Liquid Crystal display (LCD)
display is provided at the transmitter side to display the status
of the stepper motors.L298N driver is used to drive the
stepper motor. This project uses regulated 5V, 500mA power
supply, and 12 V for motors driver supply.
Index Terms—16F877A PIC microcontroller, RF module,
Stepper motor driver (L298N), Bipolar stepper motors
I. INTRODUCTION
.
In the modern world of science and technology most of
the industry is dependent on the robotics and computer related
devices. One of such methods is performing a full rotation
into a number of equal steps. Stepper motors are viewed as the
electric motors without commutators. Commutator is a rotary
electrical switch in certain types of electric motors or electric
generators that periodically reverses the current direction
between the rotor and the external circuit. A commutator is a
.
Min Chit Ko, Department of Electronics Engineering, Mandalay
Technological University, (e-mail: [email protected]). Mandalay,
Myanmar, 09-256169848
Kyaw Soe Lwin , Department of Electronics Engineering, Mandalay
Technological University, Mandalay, Myanmar, 09-5062554 (e-mail:
[email protected]).
common feature of direct current rotating machines.[3] In a
motor all the windings are part of stator. The rotor is a
permanent magnet or a tooth block of some magnetically soft
material. The motor controller should handle all the
commutation extremely. Audio frequencies are used to step
most of the stepper motors. In such cases they spin quickly.
They can be stopped and started at controlled orientations.
Stepper motors are used in simple open loop control systems,
suitable for the systems operating at low accelerations with
static loads. A stepper over-torqued in an open loop system
will result in losing all knowledge of rotor position and a
re-initialization of system is required. In this project we have
used RF modules in order to control the system wirelessly
from a remote area. We have designed hardware with
transmitting and receiving capabilities. In order to program
this hardware we have used visual basic or PIC Basic Pro
language.
II. SYSTEM DESIGN
Overall block diagram of the present project is shown in
Fig.1. From the block diagram it is clear that two PIC
microcontrollers (16F877A) have been used, one is with
transmitter side and the other is in the receiver side which may
be located at 100 meters distance and connected through the
RF (radio frequency) module. The system is used in four
control switches. The two represent for rotation of motor A
corresponding at clockwise and anticlockwise. The other
represent for motor B similar to motor A. The microcontroller
at the transmitter acts to encode the serial data and send to the
RF transmitter.16x2 line LCD display is connected to the
microcontroller to describe the status of switches on display.
The other at the receiver acts to decode the serial data giving
from the RF receiver. Two L298N motor drivers are
interfaced with the microcontroller and two stepper motors
for motor rotation.
Figure 1.System block diagram of the wireless two stepper motors control
system
III. FUNCTIONAL REQUIREMENTS
Following are the main components of this project:
1) RF Module
2) 16F877A PIC Microcontrollers
3) Stepper motors
4) L298N motor drivers
1. RF module
: 3V ~ 6V
2. 16F877A PIC Microcontroller
The PIC 16F877A is the 14-bit instrction word mid-range
microcontroller from the Microchip Technology. The
PICmicrocontroller architecture is based on RISC
(ReducedInstruction Set Computer) instruction set. The PIC
16F877A is a 40- pin device and is one of the popular
microcontrollers used in complex applications.
The device offers 8192x14 fash program, 368 bytes of
RAM , 256 bytes of non-volatile EEPROM memory, 33 I/O
pins, multiplexed A/D converters with 10-bits resolution,
PWM generator, 3 times, anologue capture and comparator
circuit, USART, and internal and external interrupt facilities.
The pin configuration of the PIC 16F877A is shown in Fig.3
Figure 2(a).RF transmitter ( KST-Tx01)
Figure 3.PIC 16F877A
3. Stepper motor
Figure 2(b). RF receiver (KST-Rx 706)
Features of RF module
TX Frequency Range : 433.92 MHz
Stepper motors operate differently from DC brush
motors, which rotate when voltage is applied to their
terminals. Stepper motors, on the other hand, effectively
have multiple "toothed" electromagnets arranged around a
central gear-shaped piece of iron. An external control
circuit, such as a microcontroller, energizes the
electromagnets. To make the motor shaft turn, first one
electromagnet is given power, which makes the gear's
teeth magnetically attracted to the electromagnet's teeth.
When the gear's teeth are thus aligned to the first
electromagnet, they are slightly offset from the next
electromagnet. So, when the next electromagnet is turned
on and the first is turned off, the gear rotates slightly to
align with the next one, and from there the process is
repeated. Each of those slight rotations is called a "step,"
with an integer number of steps making a full rotation. In
that way, the motor can be turned by a precise angle.
the lower transistors of each bridge are connected together
and the corresponding external terminal can be used for the
connection of an external sensing resistor. An additional
supply input is provided so that the logic works at a lower
voltage.
Figure.5(b) L298N pins layout
Figure.4 Bipolar stepper motor
5. Circuit diagram of the transmitter and receiver
Degree of rotation = Resolution x Number of pulses
5V
 Stepper motors are constant power devices.
 As motor speed increases, torque decreases.
 The torque curve may be extended by using current
limiting drivers and increasing the driving voltage.
 Steppers exhibit more vibration than other motor
types, as the discrete step tends to snap the rotor
from one position to another.
3
5V
1
MCLR
15
10K
1
11
32
VDD VDD
RC0
16*2 LINE LCD MODULE
VSS
D4
11
D5
D6
12
D7 RS
13
14
E
4
6
5,16
RD0 19
16
RC1
10K
5V
RD1 20
17
RC2
10K
RD2 21
18
RC3
RD3 22
10K
16F877A
27
Microcontroller RD4
RC4
 This vibration can become very bad at some speeds
and can cause the motor to lose torque.
 The effect can be mitigated by accelerating quickly
through the problem speeds range, physically
damping the system, or using a micro-stepping
driver.
 Motors with a greater number of phases also exhibit
smoother operation than those with fewer phases
10K
RD5 28
5V
22P
13
OSC1
4M
HZ
RB0
14
34
data
TX01
OSC2
22P
VSS
12
RF TRANSMITTER
VSS
31
Figure.6 Circuit diagram of transmitter
12V 100nF
5V
5V
4. Motor driver (L298N)
VEE
2 VDD
10k
470uF
8
9
3
RX706
RF
RECEIVER
4
2
7
10
12
5V
3
STEPPER
MOTOR
WINDINGS
13
L298N
data
14
1
34
MCLR/
VPP
11
32
VDD VDD
RB1
1
RB2
RB3
RB4
RB5
16F877A
Microcontroller
15 6
5V
11
35
36
37
5V
12V
100nF
470uF
38
RC2
3
RC3
7
10
12
RC4
RC5
8
4
2
3
L298N
13
15
11
STEPPER
MOTOR
WINDINGS
RD0
14
RD1
RD2
22P
13
RD3
OSC1
1
RD4
14
OSC2
22P
VSS
12
VSS
31
1
2
3
It is a high voltage, high current dual full-bridge driver
designed to accept standard TTL logic levels and drive
inductive loads such as relays, solenoids, DC and stepping
motors. Two enable inputs are provided to Enable or disable
the device independently of the input signals. The emitters of
5V
RD5
4MHZ
Figure.5(a) L298N motor driver
6
VEE
16*2 LINE LCD MODULE
VDD
VSS
D4
11
D5
12
D6
13
D7
14
RS
4
E
6
5,16
Figure.7 Circuit diagram of the receiver
IV. SOFTWARE IMPLEMENTATION FOR THE SYSTEM
To accomplish the system, the choosing of software is very
important. All PIC microcontrollers require a program or
software for their operation. This program is developed and
tested by the programmer or users. The following software
tools are normally required in a PIC microcontroller-based
project development cycle:
 A text editor
 PIC Basic Pro compilers
 PIC programmer device software
 Micro Code Studio
Micro Code Studio is a powerful, visual Integrated
Development Environment (IDE) with In Circuit Debugging
(ICD) capability designed specifically for micro Engineering
Labs PICBASIC and PICBASIC PRO compilers. This IDE
also provides a syntax highlighted to PIC Basic or PIC Pro
compilers so that the user and easily and very quickly compile
programs.
.
 PIC Basic Pro Language
In this project, PIC Basic and PIC Basic Pro languages are
used to program PIC microcontrollers. BASIC is one of the
oldest and widely known high-level programming languages.
Both PIC Basic and PIC Basic Pro have been developed by
Micro Engineering Labs Inc. PIC Basic is a low-cost compiler
and aimed at the lower end of the market, mainly for students
and programmers.
present, it is converted into parallel data format and received
data is displayed on the LCD module. If the serial data input is
not present, the program checks whether the switch is pressed
or not. If the switch is not pressed, the program skips to the
LCD display section. The serial data is then converted into
parallel data and displayed on the LCD module. If the .switch
is pressed at one time, the motor corresponding rotates one
step at 7.5 degree. If the switch is pressing, the motor
continuously rotates one step at 7.5 degree until the switch is
pressing. The program wait about one second to be
conveniently displayed on the LCD module and the program
is repeated as long as power is turned on.
V. SIMULATION RESULTS OF THE SYSTEM
The wireless stepper motor control system built based the
PIC 16F877A microcontroller is simulated using Proteus
software. Proteus consists of two main parts, ISIS and ARES.
ARES is a layout package, which is used to create a PCB
when the circuit has been designed. The schematic diagram of
the main components of the wireless motor control system
including the microcontroller circuit is drawn in the ISIS
software and then run the simulator program. A screenshot of
the ISIS schematic capture and the motor control simulation
environment is shown in the following Figures.
 Flow Chart of the System
Figure.8 The ISIS simulated screen of the wireless two stepper motor control
system
Figure.6 Flow Chart for the system
The system can be recognized easily by seeing the flow chart
of the over all system shown in figure 2. At the start of the
program, the input/output ports of the microcontroller are
configured. The LCD drive mode is also set as 4-bit mode.
The PIC microcontroller at transmitter side sends the serial
data to the receiver via RF transmitter. The serial data input
(or serial receive) is checked. If the serial data input is
Figure.9 The ISIS simulated screen of the system in data transmit and receive
mode sending request “ motor A rotating clockwise”
Figure.10 The ISIS simulated screen of the system in data transmit and
receive mode sending request “ motor A rotating anticlockwise”
Figure.14 Harding testing result in data transmit and receive mode sending
request “motor A rotating clockwise”
Figure.11 The ISIS simulated screen of the system in data transmit and
receive mode sending request “ motor B rotating clockwise”
Figure.14 Harding testing result in data transmit and receive mode sending
request “motor A rotating anticlockwise”
Figure.12 The ISIS simulated screen of the system in data transmit and
receive mode sending request “ motor A rotating anticlockwise
VI. HARDWARE TEST
Figure.13 Hardware tesing result in data transmit and recive mode
Figure.14 Harding testing result in data transmit and receive mode sending
request “motor B rotating clockwise”
Figure.14 Harding testing result in data transmit and receive mode sending
request “motor B rotating anticlockwise”
VII. CONCLUSION
In this project 16F877A PIC microcontroller and RF
wireless technology has been used to position the shaft
of the stepper motor at a desired angle which in turn
may be used in deferent application areas. As
conventional IR wireless system has short distance
limitation. IR technology has been required at line of sight.
RF technology can pass through many obstacles not required
line of sight. That, , RF technology has been used here. It
can more advance that and than other applications can be used
such as robot technology, remote control systems, remote
open door system, etc. Application of such control system
of stepper motor in remote surveillance system is the
future scope of this work.
REFERENCE
[1] Hausila Singh and Sudhansu Sharma, “Some Novel
microprocessor based configurations for controlling
Remotely Located stepper Motors as Actuators of control
valves”, IEEE Transaction on industrial electronics,
AUGUST 1991, 38(4), PP 283-287.
[2] Joao Neves Moutinho, Fernando David Mesquita, Nuno
Martins and Rui Esteves Araaujo. “Progresses On The
Design of a Surveillance System to Protect Forests from
Fire”, IEEE Conference on Emerging Technologies and
Factory Automation, 2, 16-19 Sept.2003, PP 191-194,
10.1109/ETFA.2003.1248696.
[3] D. Manojkumar, P. Mathankumar, E. Saranya and S.
pavithradevi, “Mobile Controlled Robot using DTMF
Technology for Industrial Application”, International
Journal of Electronics Engineering Research, 2010, 2( 3),
PP. 349-355.
[4] Stepping Motors and their Microprocessor controls,
Takashi Kenjo, 1994
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