electrodesigns.net

Digital should not remain a barrier for diyAudio beginners. Before the digital age, diyAudio was about designing a PCB and soldering through-hole components on it.
Nowadays, diyAudio encompasses digital. It requires designing a PCB hosting SMD (Surface Mounted Devices), and it requires creating a DSP (Digital Signal Processing) program. Those are the two new difficulties.
Ten years ago, most diyAudio enthusiasts would have failed building a digital audio system from scratch. The situation has changed. There are more and more hobbyists dealing with 32-bit microcontrollers. There are more and more hobbyists overcoming the SMD difficulty.

Here is a digital audio system built from scratch. Diptrace got used for drawing the schematic and converting it to a PCB.

The PIC32MX2 gets debugged and programmed using Microchip MPLAB ICD 3 ($189.99) . A simple experimental application would read the stereo audio entering the WM8731, apply some processing like filtering, equalizing, splitting, dynamic compression or expansion, then deliver the processed audio on the WM8731 stereo outputs. (continue reading…)

DipTrace remains free provided you don’t hit the 300 pin barrier. From a diyAudio perspective, what are the possibilities within such limit? Here are three different diyAudio boards as practical examples.
The first board hosts a PIC32MX2 coupled to a WM8731 stereo codec.
The second board is a SigmaStudio target, hosting the ADAU1701 the same way as Analog Devices EVAL-ADAU1701MINIZ.
The third board hosts a WM8580 multichannel codec delivering eight analog outputs.
The common denominator of all three boards is a 2×10 pin expansion connector allowing to stack them. A possibility is to stack PIC32MX2 acting as USB-audio device, grabbing digital audio from the PC, sending it over I2S to the ADAU1701 board. (continue reading…)

3-axis accelerometer

It’s a very simple design based on ADXL335 accelerometer chip from Analog Devices. The PCB has only one layer. The header output is provided for power input and X, Y and Z axis analog voltage representation of respective acceleration. A PDF schematic is also there if somebody is not a Diptrace fan .

Download Files:

PIC32MX1 and PIC32MX2 are the families of microcontrollers recently introduced by Microchip. These are the cropped down members of PIC32MX3/4/5/6/7 MCUs with lesser power (40MIPS) and lower number of pins. The chips host the same M4K core but with smaller program and data memories.
This all free, open source, very small (1.5″x2.0″) and simple board is an attempt to introduce a ready to use board for easy prototyping. It has a small SOIC-28 PIC32MX1 MCU. SOIC-28 is chosen because it’s easier to solder. The breakout pins can be soldered with standard 0.1″ male/female header to be easily used with veroboard or breadboard. Diptrace source files, a schematic in PDF format and Gerbers are there to download.

Download Files: