Microcontrollers are purely digital devices which work on logic0 and logic1 voltages; still they are widely used for analog signal processing. There are specialized signal processors chips available which are custom made for particular applications; however a general purpose microcontroller is more than enough for small kind of signal processing applications like audio signal input and output. The microcontroller can read the analog input voltage by sampling it and converting it to their digital values. The Analog to Digital Converter (ADC) available in almost all the microcontrollers help in this task. A timer can be used to generate the sampling time period. The sampled values can then read and modify by the microcontroller. The modified signal is then output by the microcontroller in the form of Pulse Width Modulated (PWM) waves. Most of the microcontrollers have the PWM module which helps them in generating analog voltage output at an external device.
How to Glow an LED using PWM with PIC Microcontroller- (Part 20/25)
Pulse Width Modulation (PWM) is a technique in which the width of a pulse is modulated keeping the time period of the wave constant. One cycle has a fixed time period called ‘Period’ and a varying on time called ‘Duty cycle’. The entire wave can have two voltages levels either logic 0 or logic 1. The PWM wave is very useful in the digital systems, since this can be used to generate different voltage values other than the logic 0 or logic 1 values. This feature is making use in so many digital systems like DC motor control, audio devices, simple decoration light controls etc.The PIC18F4550 has an inbuilt PWM module which can generate continuous PWM waves. The Period and the duty cycle of the PWMwave can be adjusted in program. This project explores the PWM module of the PIC18F4550 and tries to glow an LED with varying intensities, which shows that it is possible to generate any required voltage at a pin of a digital microcontroller with the help of PWM waves.
How to Generate Sound using PWM with PIC Microcontroller- (Part 22/25)
Pulse Width Modulation (PWM) is a technique in which the width of a pulse is modulated keeping the time period of the wave constant. The ON time and OFF time can have any different values in the wave cycles, but the sum of the ON time and OFF time remains same for the entire cycles. PWM is a digital wave that can be generated using digital circuits which are not capable of generating analog voltages. With the help of the modulation of the width of a pulse in a period of the wave, they can generate any required voltage with the help of a proper filter circuits. The filter circuits are used for generating the voltage corresponding to a modulated wave. This feature of the PWM wave is making use in so many digital systems like DC motor control, audio devices, simple decoration light controls etc. The PIC18F4550 has an inbuilt PWM module which can generate continuous PWM waves. This project explores the PWM module of the PIC18F4550 and tries generating a sine wave with frequency in the audible range and then produce that sound in a Loud Speaker with the help of a filter circuit and Loud Speaker driver circuits.
How to Generate Sine Wave using PWM with PIC Microcontroller- (Part 19/25)
Pulse Width Modulation (PWM) is a technique in which the width of a pulse is modulated keeping the time period of the wave constant. The ON time and OFF time can have any different values in the wave cycles, but the sum of the ON time and OFF time remains same for the entire cycles. PWM is a digital wave that can be generated using digital circuits which are not capable of generating analog voltages. With the help of the modulation of the width of a pulse in a period of the wave, they can generate any required voltage with the help of a proper filter circuits. The filter circuits are used for generating the voltage corresponding to a modulated wave. Hence the PWM wave is always associated with a filter circuit.This feature of the PWM wave is making use in so many digital systems like DC motor control, audio devices, simple decoration light controls etc. The PIC18F4550 has an inbuilt PWM module which can generate continuous PWM waves. This project explores the PWM module of the PIC18F4550 and tries generating a sine wave with the help of a filter circuit. Generating a sine wave has a great deal of importance since the sine wave is the most natural waveform and all other kind of waves can be generated as a combination of sine waves with different frequencies and amplitude.
Computer Mouse Control By Accelerometer
This project demonstrates the use of a accelerometer as a computer mouse,but first what is an accelerometer? Its a device that can measure acceleration and the pull of gravity.There are multiple ways of doing this, the particular one I’m using works with the capacitive method. Inside the chip is a capacitor with an extra plate in the middle that can move. As you know the closer the objects are together the bigger the capacitance, the circuit inside the chip measures the capacitance difference between the two plates and the middle one.