04-03-2015, 05:24 PM
PLEASE SEND ME CIRCUIT DIAGRAM OF PROJECT WIRELESS SPEED CONTROL DC MOTOR USING IR MODULATOR AND IC 555
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wireless dc motor speed control using ir and ic555
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PLEASE SEND ME CIRCUIT DIAGRAM OF PROJECT WIRELESS SPEED CONTROL DC MOTOR USING IR MODULATOR AND IC 555
14-03-2017, 10:41 AM
To make it wireless dc motor, using IR transmitter and infrared sensor. There are two sections in the circuit 1) PWM generator with IR modulator and 2) IR receiver and motor driver. The transmitter generates PWM wave of 50 Hz (20 ms) and modulates it to a frequency of 38 KHz. The IR sensor on the receiver side will demodulate the PWM wave and drive the DC motor.
First let's understand the block diagram of the system
Blocks diagram:-
![[Image: Block-diagram_0.jpg]](https://www.engineersgarage.com/sites/default/files/imagecache/Original/wysiwyg_imageupload/4214/Block-diagram_0.jpg)
PWM generator: - Its astable multi-vibrator that generates frequency of 50 Hz (that means time time is of 20 ms). We can vary the pulse width from almost 2 ms to up to 18 ms.
IR Modulator: - It is also an astable multi-vibrator that generates an exact frequency of 38 KHz. Generates an IR light beam of 38 KHz
IR sensor: - Detects infrared light beam of 38 KHz and triggers monostable multi-vibrator
Multi-vibrator monostable: - Simply reproduces the same PWM generated by the PWM generator on the side of the transmitter
DCM Controller: - Operates the DC motor using PWM (we can also change the DC motor address if necessary)
DC motor: - Its standard 12 V DC motor with maximum RPM of 1000
Circuit diagram: -
![[Image: DC-Motor-Speed-Control-Circ.gif]](http://circuitdigest.com/sites/default/files/circuitdiagram/DC-Motor-Speed-Control-Circ.gif)
The complete circuit is shown on the tab of circuit diagram 1 and is divided into different sections
1) PWM Generator: - This is an astable multi-vibrator made up of IC555. The output is fed back to the threshold and trigger inputs through two diodes D1 and D2. The frequency is given by
Freq = 1.44 / (R2 + R4) * C2
= 1.44 / 11000 * 2 * 10-6
= 65 Hz
Here, when the output is high, C2 loads through D1, part of R4 (say R4 ') and R2. When it loads more than the threshold, the output goes down. Now C2 begins to discharge through R2 another part of R4 (R4 ") and D2. Once again when discharge to the trip limit output again goes high and this cycle is repeated.If we turn R4 in the direction Clockwise, and vice versa. As we rotate R4 in any direction the output pulse width changes and we get PWM wave.
2) IR Modulator: - This is again an astable multi-vibrator. Depending on the given values of R5, R6 and C3 if we calculate the frequency value then
Freq = 1.44 / (R5 + 2 * R4) * C2
= 1.44 / [470 + 2 * 1690] * 10-7
= 37.4 KHz
As shown in the figure, the PWM output is connected to the bias pin (Vcc) of this astable multi-vibrator. So when the PWM output is high this will generate a 38 KHz wave burst. This means that the 50 Hz low frequency signal is modulated using a 38 KHz signal. As this output is given directly to the IR LED, it will generate an IR light beam of 38 KHz.
3) IR Sensor: - This sensor will detect the 38 KHz IR light beam and produce a low output. It means that the IR light falls on it its output is low and vice versa
4) Monostable multi-vibrator: - The output of the IR sensor is connected to the trigger input of IC555 which is configured in monostable multi-vibrator. Its time period again remains very low (1.1 ms) compared to the transmitted pulse time period (20 ms). So your output will be almost the same as the PWM generated on the transmitted side.
5) Motor driver: - Finally the IC555 output is given to the Darlington base pair TIP122 which is used to drive the DC motor. As the width of the pulse is more, more the speed of the engine and vice versa
Thus, as either changes the pulse width on the side of the transmitter, the motor speed changes on the side of the receiver. So we can tirelessly change the speed of the DC motor. If you wish to change the direction of the motor, then a slight change in the circuit is required. Instead of a single TIP122 we need four TIP122s to construct the H-Bridge circuit as shown in the Circuit Diagarm 2 tab
The IC555 output is given to two H-bridge inputs via the SPDT switch. When the switch is in position 'A', Q1 and Q4 are ON and Q2 and Q3 are OFF. Thus, the motor rotates in one direction. When the switch is moved to position 'B' Q2 and Q3 is turned ON and two others are OFF. Thus the motor changes its direction of rotation.
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