Check this out: sCrAmBlEd?HaCkZ!
Specifically, watch the video, as it makes a lot more sense than trying to
read about it.
I've been thinking about how to create a portable MOD tracker for
composing music away from the computer. With the sCrAmBlEd?HaCkZ! example,
the answer seems obvious. Instead of relying on a big computer screen and
keyboard like a traditional tracker, you simply include a few select
buttons, a minimal screen (if any) and a microphone. When you want to
compose music, you simply hum your notes into the microphone and the
device runs some fourier analysis against the humming (the way
Scrambled?Hackz! does) to determine what notes you want played at
what time. The device records the note information to your current
track. When you play it back, instead of hearing your humming,
it uses pre-recorded instrument samples instead, and bases the notes
off the ditty you hummed.
Think of it as a "digital trumpet," if you will. A trumpet has a
mouthpiece that you make note noises into, and three keys for further
control. A trumpet can only sound like a trumpet though, and it
does not have the ability to record what notes you played for later.
A TRAXMOD device with the proposed "voice tracker" software described
above would let you compose music on the fly, and be able to share
your music with other people beyond the live performance.
The microphone would be useful for recording instrument samples
out in the field too.
03-05-2006
Spent the last two weekends routing an LPC2101/2/3 LQFP-48 to DIP break-out
board. I've finally got everything pretty much routed. Now I just need to do a
little optimizing and then double check that everything is right before I
send it off for PCB manufacture.
This isn't the full MOD player board. I've decided that making the full MOD
player board right now is not a good idea without the break-out board.
Until I do some testing, I can't guarantee that the MOD player board will work
perfectly. The full board is quite a bit larger, so every time I send it in
for a new revision to be fabricated, it will cost more.
This break out board is pretty cool. The board size is less than 2 inches
square, so it should not cost too much to make a large pile of them for
others. It has a DB9 serial port connector on one end and a JTAG in-circuit
debugger header on the other end. The serial port connector should allow
you to FLASH program the chip in-circuit without any extra programming
circuit. The two outer edges have pin headers that will interface easily
with a bread board, as if it were a 44 pin DIP chip.
The board integrates the 32.768KHz real time clock, core processor
clock, and 0.1µF power decoupling capacitors. You still have to
provide +3.3VDC and +1.8VDC regulated power supplies off board though.
I didn't integrate that in because the errata sheet says something
about needing to possibly provide 1.95VDC when running all the peripherals
and core processor at maximum speed (one of the things I want to test).
02-25-2006
The batteries arrived. I don't really have anything to try them out with
yet, but at least I can use them to take measurements and make sure they fit
in the final product.
02-14-2006
Ordered some 1200mA NiMH AAA rechargable batteries from Germany on eBay.
I hope they arrive okay and work as advertised.
Spent the night taking measurements of the LPH7779 LCD screen PCB pads.
Started drawing up an EAGLE part library for it.
02-13-2006
Gave up trying to use the PCB mount battery contacts from Keystone
because they burn up far too much board space. I'm now thinking I'm going move
all the battery contact stuff out of the main board, and instead, have two
separate narrow strip PCBs with clip-on battery springs. Air wires will have
to connect the final series battery power PCBs to the main PCB. This makes
the main board easier to design, pushes the final battery design further out,
and solves some of the enclosure assembly problems.
Currently spending a lot of time researching linear regulators. I need to
find a low cost regulator that can provide 3.3V 150mA from an input
voltage of 4.0VDC to 12VDC (or more). I also need something to provide 1.8V
with the same input voltage requirements. There are hundreds and hundreds of
linear regulators out there, sorting through them all to find the best
choice is very time consuming.
02-08-2006
Spent the night measuring all of the components and playing with them
in various configurations inside the plastic case. Added my measurements to
the TRAXMOD FAQ. It's
looking pretty good so far, even with the batteries included this time. I
still need to work on picking out all of the parts for the in-circuit
battery charger though. Hopefully they won't need to take up more space than
we have to spare.
02-07-2006
Got the new plastic enclosure. I think I might like this better than the
Altoids tin. It's a little sleeker, a little longer (more space for the battery
contacts), a little thinner, and costs less (sort of). An Altoids tin costs
about $2. This enclosure is $1.38, but you don't get any mints.
Spent the night debating with my brother about batteries. We're now
thinking that using 4xAAA batteries is the way to go, even though that means
much less mAh. NiMH AAA batteries are up to around 800-1000mAh these days.
We spent some time drawing up a simple in-circuit battery charger. The smaller
capacity AAA batteries add less weight, free up more space for the electronics,
and make the charger circuit easier to design. I'm going to have to find some
better LDO regulators to make the in-circuit charger work though, if we
decide to actually go ahead with that.
02-06-2006
Still trying to think up how we're going to cram all of this stuff
together in a nice case. Tonight after work we're going to go pick up
one of these plastic boxes to see if it would be any better than the Altoids tin.
02-03-2006
Stopped at Sears on the way home from work today to pick up a Torx-6
screw driver. Now I can finally take apart this old Nokia 3390 cell phone and
see if I can steal the LCD off it.