In an audio play back device, the entire audio signals are separated into different bands and applied to the corresponding type of loudspeaker. The Tweeters are normally fed with frequencies above 5 kHz, Mid-range speakers are fed with frequencies in the range of 300 Hz to 5 kHz, and Sub-Woofers with 300 Hz to 40 Hz and Woofers are fed with frequencies below 40 Hz.
Since the musical sound normally falls around the maximum frequency of 5 to 8 KHz, Tweeters are not so common in audio devices. For driving the Mid-range Speakers a high pass filter of cut-in frequency around 300 Hz is enough and for Woofers a Low pass filter with cut-off frequency around 40 Hz will suffice. Bass-beats of the songs appear in the Sub-Woofer range and a Band-pass filter can be used to separate out these frequencies from the entire audio signals. This project discusses the design and implementation of a Multiple Feed Back (MFB) Band pass filter for Sub-Woofer frequencies.
This article discusses about the design of a simple audio mixer circuit. An op-amp based summing amplifier is used here to mix two sounds. The audio mixing is demonstrated with the help of mixing a high frequency musical sound with a low frequency bass beat, where the musical sound is generated by a musical IC and the bass beat played at a mobile phone and is captured and amplified through a microphone and amplifier circuits.
The different sounds in songs like the sound of the guitar, drums, the voice of the singer etc. are recorded as separate tracks using separate microphones. More than 10 numbers of tracks are very common in normal quality songs. How is such a circuit assembled? What are the major precautions and restrictions when using this circuit? Keep on reading this tutorial to find more interesting information about electronics of audio mixing.
The Snake game running on a browser window forms the GUI or front end of the entire system. In a Linux operating system each hardware device is represented as a file. In this project there is game pad which is the hardware and there is a process which reads from the game pad and there is also a Pipe file or FIFO in-between the game and the game pad reading process.
There are so many devices available which can record and playback voice. Most of the digital devices like mobile phones can use the SD card to record the voice signals and playback. This project demonstrates how to record voice signals on a micro SD card and play it back using the GR SAKURA board. Voice signals are continuous analog signals and the digital devices like microcontrollers cannot handle the continuous analog signals. Most of the microcontrollers have an ADC module which can do analog to digital conversion.
The microcontroller uses sampling technique to convert the continuous analog signals to discrete digital equivalent samples. While recording the voice, the GR SAKURA board samples the voice signals and writes the sampled values to a file at the sampling time itself. The same file is opened again and reads the values at the same frequency at which they are sampled.
A microcontroller might need to store its data like sensor value, or a particular count or image data for a long period of time. The most common type of memory used with the microcontroller based systems is EEPROM. The EEPROM stands for Electrically Erasable Programmable Read Only Memory which is a kind of Read Only Memory (ROM), which can be written and erased by means of electrically programming and hence the name. Once programmed the data it will remain in the memory for a very long time even if there is no power available.
EEPROM memory is widely used in microcontroller systems where some particular data need to be retained each time the system is turned on and to save particular data before the system is powered off.here are several EEPROM memory chips available which can be interfaced in a microcontroller based system with the help of serial communication protocols.
This tutorial is going to take you through how to make a system which senses which colour is most prominent in the background, using the same principal an LCD screen uses to display colour. It’s is relatively simple to make, while the code is of moderate length. The output is in the form of a hexadecimal value, which is the accepted norm for representing colours, and can be typed in to any picture editing application like paint or Photoshop to give you the resulting colour on your screen.
Each pixel on any LCD or LED monitor you own consists of three ‘sub-pixels’ which are nothing but red, green and blue lights. These lights combined make up the 16.9 million colours that are commonly advertised. Each LED is given a voltage value from 0 to 256,to adjust its brightness from completely lit to unlit. This corresponds to an 8-bit hexadecimal number.