Not Even Remotely Funny

Sunday, February 24, 2008

Transistor Matching

Simple matching for BJT, JFET, and MOSFET:

http://www.diamondstar.de/transistor_matching_bjt.html

Monday, February 18, 2008

Scrobbling to last.fm from Perl

Here's some Perl that allows you to scrobble directly to your last.fm profile.

First install the following modules. The first pulls tag metadata out of MP3 files, while the second sends the information to last.fm.

http://search.cpan.org/~daniel/MP3-Info-1.23/Info.pm

http://search.cpan.org/~roam/Audio-Scrobbler-0.01/lib/Audio/Scrobbler.pm

(to install these use: perl -MCPAN -e 'shell', then install MP3::Info, and install Audio::Scrobbler)

use MP3::Info;

use Audio::Scrobbler;

my $info = get_mp3info($file);

my $tag = get_mp3tag($file) or die "No TAG info";

my $mp3_title = $tag->{TITLE};

my $mp3_artist = $tag->{ARTIST};

my $mp3_album = $tag->{ALBUM};

my $mp3_length = int($info->{SECS});

$scrob = new Audio::Scrobbler(
cfg => {
progname => "tst",
progver => "1.0",
username => "someone",
password => "somepass",
verbose => "1"
}
);

$scrob->handshake();

$scrob->submit(
{
title => "$mp3_title",
artist => "$mp3_artist",
album => "$mp3_album",
length => "$mp3_length"
}
);

Saturday, November 17, 2007

LT Spice Simulator

Linear Technology has a great Spice simulator available as a free download. Enter the circuit using the schematic editor, specify the stimulus, run the simulation and then plot the results.

Attached is an example circuit and the output plot. The circuit is a simple log converter.

Yahoo support group (~10K members): LTspice

Schematic/PCB Tools

More collected wisdom from SDIY, summarized by platform, capability, cost and support. Another useful metric would be library depth, but that's too much work for today. Presented in alphabetical order:

DipTrace

Windows commercial product
Full suite of tools
250 pin limited freeware version to $695 full, non-profit version $125
Yahoo group (~1000 members) : diptr

Eagle

Linux, Mac, Windows commercial product
Full suite of tools
Limited freeware, Standard $398, Pro $798, autorouter additional
Official News groups for support: eagle.support.eng
Yahoo group (~800 members): eaglecad

FreePCB

PCB Layout only
Windows
Open Source
Yahoo Group (~450 members): FreePCB

gEDA

Full suite of tools
Linux
Open Source
Wiki

Kicad

Full suite of tools: Schematic Editor, PCB Layout, Gerber Viewer
Multi-platform Linux, Windows, Mac(?)
Open Source
Multi-language support
Yahoo group (~1650 members): kicad-users
Sourceforge Wiki

Osmond PCB

PCB Layout only
Mac OS-X
Yahoo group (~350 members): osmondpcb

Rimu Schematic and PCB

Windows commercial product
Schematic Editor full version $149
PCB $72.50
No apparent forum or users group

TinyCad Schematic

Schematic Editor
Opensource
Windows only
Yahoo group (~1850 members): tinycad

Monday, November 12, 2007

SMT Prototyping Board Suppliers

Collected wisdom from sdiy:

One Pas has a fairly wide selection, combined SMT and thru-hole, endorsed by Forrest Mims. Also sells pcb drills. ebay store

Bellin Dynamic Systems about $45 bucks for a break apart board. Sold by JameCo, Mouser

ePBoard SMT to DIP adapters, online ordering