They’ve just released a new board they call their Boss Board. It has spots for a PS2 connector, Audio/Video jacks, and even an NES controller (where do you get the connectors??).

The more I get into etching my own PCBs, the more I see the value in pushing out a project quickly with a protoboard. It doesn’t look as nice, but it’s just a LOT easier.

8317 Embossed Note Card Template for Photoshop (PSD)

The trick is to use the “last_buffer” property on your video sink. That contains the last frame that was displayed to your screen.

You can use RMagick to convert that into something you can use like this:

#!/usr/bin/ruby

require 'gst'
require 'RMagick'

@pipe = Gst::Pipeline.new
@source = Gst::ElementFactory.make("v4l2src")
@sink    = Gst::ElementFactory.make("xvimagesink")
@pipe.add(@source,@sink)
@source >> @sink

@pipe.play

[ ... Later ... ]
# This is the actual capture.
capture = Image.from_blob(@sink.last_buffer.data).first

It’s embryonic, but it works. I’d like to do a little more input sanitation, since it’s certainly possible to really hurt your server by requesting a kstat value of “::” (which returns all stats).

Here’s the server code:

require 'soap/rpc/standaloneServer'

class StatServ < SOAP::RPC::StandaloneServer
        def initialize(*args)
          super
          add_method(self, 'kstat', 'stat')
        end
        def kstat(stat)
                stat.gsub!(/[^a-zA-z0-9_:+]/i,'%');
                f = IO.popen("kstat -p #{stat}")
                return f.readlines
        end
end

server = StatServ.new('StatServ,'urn:StatServ','0.0.0.0',8888)
trap('INT') { server.shutdown ; puts "Server shutdown."}
trap('TERM') { server.shutdown ; puts "Server shutdown."}
puts "Starting server..."
server.start

…and the client code:

require 'soap/rpc/driver'
def usage
        puts "Usage: #{$0} hostname kstatvalue"
        puts "   Retrieves a kstat value from a remote machine's StatServ SOAP Server."
end

hostname = ARGV[0]
value    = ARGV[1];


if ! value
        usage;
        exit 1;
end

driver = SOAP::RPC::Driver.new("http://#{hostname}:8888/", 'urn:StatServ')
driver.add_method('kstat', 'stat')

val = driver.kstat("#{value}")

val.each do |s|
puts "#{s}"
end

Powered by Twitter Tools.

It’s an 8×8 red+green LED Matrix, driven by three shift registers driven by a Bare Bones Board Freeduino by Modern Device Company.

Before the meeting I just had it flashing fun patterns based on odd bit-math equations. During the meeting, I was urged to add some code to make it controllable by the Wii Nunchuk. So, I wrote a simple program that takes the X and Y of accelerometer and plots it on the matrix.

I drove the LED Matrix with three shift registers: One 74HC595 8-bit register gave power to the rows of the display, and one Maxim-IC MAX6969 sank current for the columns to the display. To turn on row 1, column one, you shift “B10000000″ into the row register, and “B10000000″ into the column register:

  1 0 0 0 0 0 0 0  
1 x o o o o o o o
0 o o o o o o o o
0 o o o o o o o o 
0 o o o o o o o o 
0 o o o o o o o o 
0 o o o o o o o o 
0 o o o o o o o o 
0 o o o o o o o o 

Altogether, it was about 30 lines of code to drive the matrix with some fun patterns.

I’m psyched. I have some projects I want to do that these boards will be perfect for.

You blow the center pole towards one side, and the LED shuts off. To turn it back on again, blow it the other direction. It’s a circuit known as a bistable multivibrator, or “flip-flop”.

I do like that it’s so simple and cheap, though.

My parts list is simply:

2 – 10k ohm resistors
1 – 1k ohm resistor
1 – 220 ohm resistor
2 – 2n3904 NPN Transistors
1 – LED
3 – AAA batteries (this thing’ll last forever!)

Not including the batteries, this thing costs less than 15 cents in parts. If I could work out the “blow” mechanism a little better, I think this would be a marketable product.

Okay, now for some photos:

On the breadboard:

Before being shoved in the pill bottle:

I had originally wanted to be able to shove this thing into a fat straw, like you get with a bubble tea, so I made it as small as possible, and soldered the pieces together straight rather than using protoboard:

Next: Brighter LEDs!