The project aims at designing a system, capable of controlling speed and direction of a dc motor wirelessly through a remote control. IOT wireless technology is employed in the project. A pulse width modulator (PWM) is a device that may be used as an efficient DC motor speed controller. This project is a versatile device that can control DC devices which draw up to a few amps of current. The circuit may be used in either 12 or 24 Volt systems with only a few minor wiring changes. This device has been used to control the speed of the DC motor and to control brightness of an automotive tail lamp. A PWM circuit works by making a square wave with a variable on-to-off ratio, the average on time may be varied from 0 to 100 percent. In this manner, a variable amount of power is transferred to the load. The main advantage of a PWM circuit over a resistive power controller is the efficiency, at a 50% level, the PWM will use about 50% of full power, almost all of which is transferred to the load, a resistive controller at 50% load power would consume about 71% of full power, 50% of the power goes to the load and the other 21% is wasted heating the series resistor. One additional advantage of pulse width modulation is that the pulses reach the full supply voltage and will produce more torque in a motor by being able to overcome the internal motor resistances more easily. Wi-Fi (Short for Wireless Fidelity) is a wireless technology that uses radio frequency to transmit data through the air. Wi-Fi has initial speeds of 1mbps to 2mbps. Wi-Fi transmits data in the frequency band of 2.4 GHz. It implements the concept of frequency division multiplexing technology. Range of Wi-Fi technology is 40-300 feet.   The main controlling device of the whole system is microcontroller. DC motor along with driver and Wi-Fi module is interfaced to the microcontroller. When the user presses the buttons on his mobile phone, this data is received by Wi-Fi module and take the appropriate action on DC motor. In achieving the task, the controller is loaded with a program written using Embedded ‘C’ language. This project uses regulated 5V, 500mA & 12V, 500mA power supply. 7805 and 7812 three terminal voltage regulators are used for voltage regulation. Bridge type full wave rectifier is used to rectify the ac out put of secondary of 230/12V step down transformer.  

The main objectives of the project are:  

1. Remote based controlling of DC motor speed and direction.
2. Usage of IOT technology.

  The project focuses on the following areas:  

1. IOT technology.
2. WI-FI operation.
3. Embedded C programming.
4. PWM concept
5. Conversion of AC supply to DC supply.
6. H-bridge concept.
7. PCB designing.

  The major building blocks of this project are:  

1. Regulated Power supply.
2. Microcontroller
3. DC Motor with driver.
4. Reset
5. WI-FI module.
6. Crystal
7. LED indicators.

  Software’s used:  

• PIC-C compiler for Embedded C programming.
• PIC kit 2 programmer for dumping code into Micro controller.
• Express SCH for Circuit design.

 

Block Diagram:

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