Turn-key PCB assembly services in prototype quantities or low-volume to mid-volume production runs

Playing stereo audio with PIC32

PIC32 microcontroller has enough power to many great things. One of these is playing stereo audio. Tahmid thought it would cool to make one of these an a minimal board without audio amps and fancy interfaces. He interfaced microSD card to microcontroller which is accessed with Microchip Memory Disk Drive File System (MDDFS) library. Audio is sampled by using external dual channel MCP4822 12-bid DAC. With this setup he is able to play 16-bit 44.1kHz WAV files. Playback program has an automatic period configuration which enables automatic playback of different resolution and rates like 8-bit, 16-bit mono and stereo. Continue reading

Multimeter hacked with talk module

Talking gadgets may be annoying, but sometimes they can be a big helpers. One situation – blind people. Voice messages can help make electronics useable. Another situation is when you can’t look at display due to complex task you are doing or you are in position when you cannot see it. Either way voice on devices might be useful. MastroGippo had a request to convert multimeter into talking one. He found out that there is no many multimeters on market that talks. Some of them are expensive, while other discontinued. Instead of struggling to find one he started hacking. He found that simplest and cheapest way is to play prerecorded sounds with Arduino. He stored number waves in to SD card. Another problem is number pronunciation in different languages. Luckily… Continue reading

Playing wav files with Arduino

Sound functionality can push your design to new level. It may seem that playing recorded sounds with micros like AVR is quite intense, but in reality this is easy. And the only limitation here is memory storage. Husham Samir published his instructable on how to play wav files with Arduino Nano 3.0. His set up uses SD card for storing wav files striped to to 8-bit and 16000Hz sampling. This indeed is enough to get decent quality of voice messages. There are four buttons used that allow selecting one of four files to be played. Player code relies on TRMpcm library which is specially created to play PCM/WAV files directly from SD card. Continue reading

Parallax Propeller music player

Building MCU based music player is a good exercise for hobbyists today. This time take a look at propeller based MP3 player design. It has everything a decent player has – a regulated power supply (9V battery), buttons, audio amplifier, accelerometer input, LED and SD card reader to read songs out of flash card. As project supposed to be finished in one day – this is pretty raw design with no intention to put it in to enclosure. Anyway it plays wav files as there is no mp3 encoder used. So be sure to pick large capacity SD card for mp3 to wav converted files. There were some intentions for future improvements where accelerometer would be used for basic controls. But for now – not bad for one day project. Continue reading