Here is my project on interfacing of SD Card (microSD). MicroSD cards are available very cheap nowadays, a great option for having a huge memory in any embedded system project. It is compatible with SPI bus, so interfacing is easy. SD card adapters are also easily available in market, so one can easily make an bread-board adapter by soldering few pins on it.
In this project, I've used 1GB microSD card from sandisk (later on tested with transcend card also) The microcontroller is AVR ATmega8 running at 8Mhz internal clock. MAX232 is used to interface the circuit with PC for monitoring the data. A 3.3v supply is used for powering the mega8, microSD and max232.
Posted on Tuesday, March 24, 2009 • Category: Audio Attenuators
The circuit provides both audio volume and input channel selection. A stepwise volume control is implemented with a set of tiny relays and RN60D / RN55D Dale resistors. In a high-end audio system, a noticeable sound improvement over potentiometers is obtained, also compared to 'audio grade' potentiometers. Its IR remote control provides convenience over solutions with stepped attenuator rotary switches. The sealed relays will maintain contact quality over a practically endless lifetime. The design represents a audio 'preamplifier' of top-class sonic quality, in a compact and affordable implementation.
Compact and simple circuit with just 6 tiny relays implement a 64-step logarithmic stereo attenuator. The 64 steps of 1.0dB together span a 63dB audio attenuation range. By avoiding any active electronics, a very clean and open sound is maintained.
An IR receiver allows remote control. The IR 'eye' and a numeric display are on a small front-mount printed circuit board, separate from the relay board. The device can learn and store your favorite key codes. The controller understands the popular Philips 'RC5' protocol, Philips' newer 'RC6' protocol, and Sony's SIRC protocol. This also ensures interoperability with all 'generic' IR-controllers.
Posted on Friday, January 30, 2009 • Category: Audio DAC
24-Bit 192KHz PCM1793 DAC is is perfect solution for upgrading audio components such as CD Player, DVD Player, Blue Ray Player, Computer, and Satellite receiver. It can be easily connected via Coaxial S/PDIF or Optical Cable and provides convenient analog output connectors. PCM1793 Audio DAC board features advanced Burr-Brown PCM1793 DAC chip, high quality OPA2134 op-amp, and latest DIR9001 digital line receiver. PCB board is built with high quality components such as Nichicon Audio capacitors, WIMA capacitors, gold plated connectors, gold plated PCB tracks and metal film resistors. PCM1793 DAC provides detailed heights and exceptionally good sound stage.
PCM1793 DAC Specifications
- Burr-Brown PCM1793
- 24-Bit 192kHz Sampling Advanced Segment Audio Stereo DAC
- Dynamic Range: 113 dB THD+N: 0.001%
- 8× Oversampling Digital Filter
- Digital input receiver DIR9001
- Burr-Brown OPA2134 OPAMP
- Coaxial / Optical Inputs, Analog Output
- Nichicon KZ Audio capacitors, WIMA capacitors
- The receiver provides better quality than the popular CS8412 / CS8414 / CS8416
- Power Supply: 12V / 1A
Posted on Tuesday, December 2, 2008 • Category: PIC
Build your own LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and "Zero Out" function to make sure the readings are as accurate as possible ...
Posted on Monday, November 10, 2008 • Category: FM Transmitters
Here is a stereo FM Transmitter based on BH1415F wireless audio link IC. Phase Locked Loop controller use Microchip PIC16F628 and the the PLL frequency programming can be displayed with 8×2 and 16×2 LCD display. The frequency range can adjustable from 88-108 MHz.
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