Another headset plug-in detection from Texas Instruments. Link here (PDF) The headset detect circuitry can differentiate between mono, stereo, mono with microphone, and stereo with microphone headsets. It can operate while the LM4935 is placed into low current standby mode, which promotes extended battery life. In standby mode, it consumes no extra current, if the […]
Tag Archives: audio
App note: WM9712 Jack plug auto-detection, hookswitch detection and microphone headset detection
App note on Cirrus Logic’s WM9712 jack plug auto-detection by monitoring the connected headphone resistance. Link here (PDF) This application note describes two operations associated with using headset. The first is the facility to automatically switch between a mono ear speaker and stereo headphones for use in a Smartphone, PDA etc. The second operation is […]
flip-flop/BCF project
Ray over at the diyAudio forum has been working on his flip-flop/BCF project: I’ve just finished a project to roll up the developments into a more ‘finished’ build, feeding the balanced outputs from the flip-flop board into a Broskie BCF buffer stage. I’m using Nicks MJ Statistical Regulator for the B+ and one of Andrew’s indirect filament […]
Replacement LED driver for AN6877
Dilshan Jayakody writes: AN6877 is linear AF level meter IC produced by Panasonic and it is commonly found on many audio equipment. This chip is no longer manufactured by Panasonic and finding replacement chip for AN6877 is also quiet difficult. The circuit described in this article is design to replace AN6877 base LED drivers and it […]
Audio multiplexer with integrated amplifier
Audio multiplexer with integrated amplifier project by Matt Winslow, built as a capstone project for his masters in EE: This project is to act as a central hub for switching between audio sources and listening devices. Multiple audio sources can include a phone, computer, TV, etc. The listening devices can include different sets of speakers, […]
Dynamic microphone preamplifier
Dilshan Jayakody published a new build, a microphone preamplifier: This is single chip dynamic microphone preamplifier which is design to drive using commonly available 12V single rail power supplies. Preamplifier in this article is build around popular NE5532 dual low noise operational amplifier IC and this preamplifier is specifically constructed to drive professional 600Ω dynamic microphones. This […]
48V Phantom power supply
Dilshan Jayakody has designed and built a 48V Phantom power supply: Phantom power supply is widely used in audio industry to power the active microphones over single audio cable. Most of the phantom power supplies deliver 48V DC over the balanced audio link and power supply unit described in this article is also based on same […]
Calculator for audio output transformers
Dilshan Jayakody writes: Audio output transformers are heavily used in vacuum tube and some (older) transistor base audio power amplifiers, but these days output transformer are quiet hard to find and expensive item. For homebrew projects the best option is to construct those transformers by ourselves and this script helps to calculate winding parameters […]
Homebrew audio signal generator
Dilshan Jayakody writes: Audio Signal Generator (or AF Signal Generator) is often used in RF and AF base designing and experiments. In this article we introduce less complex AF signal generator based on commonly available electronic components. The heart of this AF signal generator is Intersil ICL8038 precision waveform generator/voltage controlled oscillator IC. ICL8038 is […]
Soundbar design from start to finish
Dafydd from Hacker Camp Shenzhen vol 2 works at TI and wrote this app note: The future of consumer home audio has shifted. The priority has moved from having speakers and wires all over the living room to a single, intelligent product capable of emulating the audio experience of other multi-speaker installations. This is normally […]
3 tone siren project
Rajkumar Sharma over at Electronics Lab published a new build, a 3 tone siren based on UM3561 IC: 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.
Voice echo project
A voice echo module with build-in amplifier project by Rajkumar Sharma of Electronics Lab: A project has been designed around Holteks Ht8970 voice echo IC. Project can be used in various audio systems karaoke, toys, animatronics, show, display, exhibitions, and sound equipments. The HT8970 is an echo/surround effect processor. It is designed for various audio systems […]
60 seconds voice record – playback module
A 60 seconds voice record – playback module project by Rajkumar Sharma of Electronics Lab: Voice Module 60 Sec project will playback and record up to 60 seconds of voice message. This circuit is an excellent choice to add voice to your project.
DIY LM1876 dual 20W audio power amplifier
An audio power amplifier based on LM1876 from Electro Labs: We are building another enjoyable weekend DIY project. This is an audio power amplifier based on LM1876 which can deliver up to 20W per channel into 4 or 8 ohm load and guarantees less than 0.1% THD + N (Total Harmonic Distortion + Noise). The amplifier is […]
Measure audio level using root mean square on Spark Core
Davide Gironi writes: A Spark.io library to retrive RMS and Spl value from an audio input. This library reads data from an ADC pin and returns the RMS value of the input simply using RMS avarage. The root mean square (abbreviated RMS or rms), also known as the quadratic mean, is a statistical measure of […]
120 seconds voice record – play back
A message recording board capable of recording 120 secs of audio by Rajkumar Sharma over at Electronics Lab: This project is designed around ISD25120 which can store 120 Seconds audio. Recording and playback operations are controlled with tact switches. The kit has an onboard microphone and LED to indicate the functions of Play and Recording. IC has […]
Audio: Headphone “Anti thump” delayed output rev 1.1
Rupert Hirst writes: A long awaited refresh, to my previous “Anti Thump” headphone output delay circuit, designed back in 2011. The Idea behind the circuit is to introduce a small delay, during initial power up, to electrically isolate and protect equipment connected directly to an amplifier. Often, during power up, amplifiers can produce an audible […]
Serial audio player with amplifier
Chris Holden writes: Steve Carpenter wants some wav playing boards, so I redesigned the circuit to use an integrated op-amp, so they just require power and a speaker. I’ve no idea which op-amp works best, a TL072 or an LM386 (I’ve not had much luck with the LM386 in the past, and Steve really rates […]
ChipStomp, a digital effects pedal with a ChipKit DP32 and Stompshield
Catmacey has been working on a digital guitar effects processor based on a PIC32MX, the ChipStomp: Here’s another “Guitar stomp box” project… This one combines a Chipkit DP32 (PIC32MX) with an Open music labs Stomp Shield to sample audio, mess with it and squirt it back out at 44Khz. It uses the built-in 10bit ADC for input […]
Hi-Fi audio power amplifier for experiments and general use
Dilshan Jayakody writes: This is high quality audio power amplifier which we constructed for our audio related experiments. This amplifier is based on NXP’s TDA1521A integrated circuit and it is capable to deliver 2 × 6W audio output power with 20V – 25V asymmetrical power source. The design of this power amplifier is heavily based […]