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Archived News

03-23-2006

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.

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).

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.

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.

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.

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.

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.

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.

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.

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