Custom Recording Mixer: Part 2

I place my order to BatchPCB.com for channel strip boards about a month ago. They finally arrived last week and I can finally get to make some real progress on this project. I was pleasantly surprised to receive a double order of my pc boards at no extra cost (which is good because I ordered exactly half of what I needed). I was able to spend a fair amount of time putting things together and testing them out this week. I managed to get all the holes drilled in the case and began populating the boards (which look and sound great).

DIY Condenser Electret Mic

For recording enthusiasts and diyers everywhere, there is DiyCondenserMics.com.

Overview:

If you're not afraid of a soldering iron, you can actually build a +48v phantom powered studio condenser mic, for fairly cheap. Most, if not all of the parts can be found at your local Radio Shack. The only thing you really need to find, or make your self, would be the mic body. People have come up with all kinds of ideas for mic bodies. From old flash lights, to pluming parts, to Altoids tins.

The site features build pics, schematics, and construction plans as well as a forum for sharing ideas and other treatsies.

P.S: The move into the new place is going well. ethernet is going in this week, painting is ongoing and a true transformation can be expected in the near future. Pictures to come soon!

New Years Resolution: Removable Media Backup

Removable and portable media, I've found, is one of the toughest things to make consistent backup copies of. After all, there is really no way to predict when and/or where my multitude of drives will be plugged in. Which led me to a simple solution, back them up when they are plugged in.

In the past, I've used rsync to make backups on a regular basis (using cron jobs). I devised a similar scheme to backup removable media.

A simple python script scans for mounted media. Drives that have been configured to be backed up are copied through rsync and ssh to the specified backup location. Drives/media not configured for backup are simply ignored.

The script looks for a two line text file in the root directory of each mounted drive to designate whether or not to backup the drive. The text file contains the volume's name (not to be confused with the portion label, this name is only for aesthetics and organization) and also the location the drive should be copied to on a remote host. The script then continues to archive the drive to the location specified. When done, it moves on to the next drive and so on.

The script and example config file are included in a tarball below. Comments and improvements welcome.

Download the Drive Booty script [Box.net link]


DriveBooty by Dana Simmons is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.

Arduino Control Voltage: Rough Code

I've worked a little more on the Arduino Control Voltage. The processing code bellow takes midi input from any midi device, reads the note and velocity information and then spits it back out over the USB Serial connection to the Arduino board. It's a roundabout convoluted way of getting midi information (midi being a serial data stream to begin with), I hope to get a direct midi input wired up soon.
Arduino PWM to CV out circuit

import promidi.*;
import processing.serial.*;

int com = 0; //Comport/Serial port #
MidiIO midiIO;
Serial sOut;
PFont font;
int pit;
int vel;
void setup(){

font = loadFont("ArialMT-40.vlw");
midiIO = MidiIO.getInstance(this);
println(Serial.list());

midiIO.printDevices();

midiIO.plug(this,"getMidi",0,0);
sOut = new Serial(this, Serial.list()[com], 9600);
}

void draw(){
background(255,255,255);
textFont(font,15);
fill(0,0,0);
text("Midi Data",0,14);
textFont(font,12);
text("Note:",0,28);
text("Velo:",0,42);
textFont(font,12);
text(pit,42,28);
text(vel,42,42);
}

void getMidi(Note note){
println("Got a note!");
vel = note.getVelocity();
pit = note.getPitch();
println(vel);
//println(pit);
sOut.write(vel);
sOut.write(pit);
}

Bellow is the (now) simple code to be uploaded to the Arduino board which just reads the serial data and controls the PWM output.

/*Arduino CV. Reads note and velocity information form the serial line and outputs to PWM pin */
byte note = 0;
byte vel = 0;
int synPin = 11; //Pin # for pitch CV output

void setup() {
Serial.begin(9600);
}

void loop() {
if(Serial.available() >= 2 ){ //Wait untill there is enough information
Serial.println(Serial.available(),DEC);
vel = Serial.read(); //FIX ME: Implement velocity sensitivity (VCA Control)
note= Serial.read();
analogWrite(synPin,note);
}

}

Arduino Control Voltage by Dana Simmons is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.
Based on a work at code.google.com.

Prelminary descrete circuitry guitar amp.

Above is pictured a very simple and wonderfully bad guitar amp circuit. The output is weak and horribly distorted but it works and can sound quite interesting.

After doing more research I noticed a striking similarity to my circuit and an NPN based Fuzz Face circuit

New Linux box!! Hurray!

Just like the title says, I put the finishing touches on a new home network/backup/print/file/misc server box this past week. Of course I took lots of pictures (to be posted soon) but I've included the specs for the new machine below.

- GeForce 7050M mobo
- AMD Athlon64 1620 cpu
- 512 MB ram
- 2x 500 gig Maxtor SATA drives (RAID 1 backup system)
- 1x 80 gig Maxtor IDE system drive
- Micro ATX form factor
- Debian 64 bit operating system

Pictures to come soon!!

Headphone/Monitor Switch in a can

Frustrated with having my monitors and headphones amp on separate outputs. I cooked up this wacky and simple switcher to select where to send the main outputs from my desktop workstation P.C.

Basically it is just a DPDT switch wired up to a set up 1/4" TR inputs, fed from outputs 1 and 2 of my sound card. The switch can either trow the signal to the headphones amp or the monitors. I simply grabbed the closet empty semi rigid container I could find  (I.E: empty soda can) to house the wiring and such. In the pictures below I've only completed 2/3 of the wiring as I still have to add a second set of outputs (I ran out of female 1/4" TR plugs). Thus, in it's current state it simply acts as a glorified on/off switch. Once I get some more TR plugs I'll put it all in a proper enclosure and it will find a happy home on my desk. Build pictures bellow.

I scavenged some 1/4" female plugs from an old mixer. Bellow are all the build materials (minus two female TR plugs of course)

Here is the can with the holes punched out, I just used a flat head screwdriver and a little ub3r skill to cut "X"s in the aluminum, then simply folded the corners in.

Soldering the TR plugs:

Inside the can after all the TR plugs are installed

After the switch gets installed

And finally 2/3 of the finished project