Home Blog  





24 Feb 2015

MIC_PRE-AMP_PIC

This is easy to construct microphone pre-amplifier project using compact electret condenser microphone. The pre-amplifier is important building block of many audio communication systems. Circuit has been built around Op-Amp LM358.

– Power supply : 5 to 12 VDC @ 10 mA
– Output: Gain Approx. 100
– On-Board electret condenser microphone
– Header connector for connecting of power supply input and audio output
– Power-On LED indicator
– Four mounting holes of 3.2 mm each
– PCB dimensions 35 mm x 40 mm

MIC Pre-amplifier - [Link]

3 Feb 2015

2013-08-03_15-21-37

by acidbourbon @ acidbourbon.wordpress.com:

Though I am a musician I don’t care for calling an expensive hi watt stereo my own. For years I have used a homebuilt stereo amplifier built around the TDA1554Q IC (basically just this chip in a nice box) and I am still very happy with the sound quality. This amp serves as a computer desk sound system, which acts as a radio/movie sound sytem as well.

In the meantime the number of sound sources that I want to connect to my “stereo” has increased … suddenly there was a tablet that I use as an internet radio, a music player demon that runs on a raspberry pi and from time to time I want to listen to a podcast that I downloaded to my smartphone.

Digitally Controlled HiFi Amp with 4 way mixer - [Link]

23 Jan 2015

iw48w41

A USB DAC designed using a TI PCM2707:

it was a very fun project and very fulfilling to make something that I actually use everyday. Overall the audio specs aren’t anything amazing, but it definitely is an improvement on the built in audio of my computer.

DIY USB DAC - [Link]

8 Jan 2015

HEF4046BT

Infrared headphones can be used for listening to music or television cordlessly. The headphones utilize a transmitter that connects with audio cables to the audio source, such as a home entertainment center. The transmitter utilizes light-emitting diodes (LEDs) to direct a focused beam of invisible pulsating light towards a receiver built into the headphone set. The pulsations act as ON/OFF signals that are translated digitally by the receiver into audible sound waves. Most infrared headphones have an effective range of about 30 feet (~10 meters) or less, and require a clear line of sight between transmitter and receiver.

Sound comes out of the stereo system through audio cables and into an infrared transmitter. The transmitter turns the sound into a series of pulses. The pulses work like bits in a computer, digitally capturing the sound information. These pulses are then sent to an infrared LED.

For the transmitter side, an audio input from PL1 frequency modulates the VCO section of a HEF4046BT PLL chip. The VCO output drives Q1, a switching transistor. Q1 drives two IR LEDs. The signal produced is around 100 kHz, FM carrier VCO sensitivity is around 7.5 kHz/V.

Wireless IR Headphone Transmitter – [Link]


24 Dec 2014

LED_VU_Meter_(3)_th

LM3916 is a dedicated IC for VU LED meter. Unlike LM3915 which have 3dB step between voltage levels, the LM3916 have nonlinear steps: -20, -10, -7, -5, -3, -1, 0, +1, +2, +3db, just like old school analog VU meters. I saw in YouTube an interesting commercial LED VU meter, which imitates the needle movement in analog VU meters and I thought I can make a similar one. All I needed I found in the datasheet of LM3916.

LED VU Meter with LM3916 - [Link]

12 Dec 2014

LM3886(1)_th

This is my second encounter with LM3886. I was pleased of the sound this chip produced the first time, so I decided to make another amplifier with it. The schematic is based on the schematic in the datasheet of the chip with minor changes.

I removed the time delay capacitor connected to MUTE pin, because it’s better to use separate DC protection schematic which has similar functionality. I made the output inductance L1 by winding 15 turns of enameled wire around the resistor R7. The diameter of the wire must be minimum 0.4mm. The whole was wrapped with heat shrink. I used 47uF/63V non polarized capacitor for C2. It can be regular electrolytic capacitor, but it’s better to use non-polarized or bipolar.

50W Power Amplifier with LM3886 - [Link]

27 Nov 2014

photo_1_th

This project is an audio amplifier based on TDA2050 and LM1875.

This is not an ordinary project, but an attempt to make a PCB that is suitable for TDA2050 and LM1875 and has all the necessary circuitry on board – power supply, speaker protection, delayed turn-on and fast turn-off. This is achieved using the convenient uPC1237 IC.

TDA2050 and LM1875 are pin to pin compatible, the differences in their schematics are the values of a couple resistors and one capacitor. All this allows to make an universal circuit board, suitable for any of these two ICs.

Audio Power Amplifier with TDA2050 - [Link]

22 Nov 2014

3_TONE_SIREN_PIC

3 Tone Siren project produces Gun Sound, Police Siren and Ambulance Siren effects from a speaker. This project is built around UM3561 IC driving an LM386 audio amplifier to give that extra punch.

3 Tone Siren - [Link]

10 Nov 2014

FPF9WNXI28OCUU2.MEDIUM

by MrLeeh @ instructables.com:

I wanted to have my personal, nice looking Mediabox with a big display and remote control. I’ ve been playing around with the Raspberry for a while so I decided this would be the platform of choice for this project. I’ m actually a fan of Steampunk so I decided to use a Steampunkish style for the box.

Raspberry Mediabox Steampunk style - [Link]

5 Nov 2014

HEF4046BP

Infrared headphones can be used for listening to music or television cordlessly. The headphones utilize a transmitter that connects with audio cables to the audio source, such as a home entertainment center. The transmitter utilizes light-emitting diodes (LEDs) to direct a focused beam of invisible pulsating light towards a receiver built into the headphone set. The pulsations act as ON/OFF signals that are translated digitally by the receiver into audible sound waves. Most infrared headphones have an effective range of about 30 feet (~10 meters) or less, and require a clear line of sight between transmitter and receiver.

The headphones pick up the light with a receiver and turn it back into sound. The receiver has an infrared CDS cell, which produces a pulse of electricity every time infrared light lands on it. The cell is designed to pick up the particular frequency of light produced by the transmitter, so it is not disturbed or thrown off by other light. A small computer inside of the receiver takes these pulses of electricity and turns them into an audio signal. This audio signal is then amplified and sent to the headphones themselves, which play the sound.

For the receiver side, a photodiode D1 feeds high gain IR remote control preamp IC, a CA3237E. U2 is a PLL FM detector tuned to around 100 kHz. The detector output is amplified by U3 and it can drive a speaker or a set of headphones.

Wireless IR Headphone Receiver - [Link]



 
 
 

 

 

 

Search Site | Advertising | Contact Us
Elektrotekno.com | Free Schematics Search Engine | Electronic Kits