Friday, June 11, 2010

Ordered SheevaPlug

So I went ahead and put in an order for a SheevaPlug. They say it will take "2-3 weeks" from order date. I ignored the GuruPlugs because of the reported heat problems. I may use the SheevaPlug as a "more reliable/powerful" network interface for physical computing systems like Arduino that can hang off of its USB. I may also use it as an el-cheapo "meet-in-the-middle" server for PHY2PHY projects.

No sooner had I ordered the SheevaPlug did I see a neat mini-systemboard ALIX3d2. LAN / 2 miniPCI / LX800 / 256 MB / USB / 500 MHz AMD Geode LX800, $99. Needs an external DC power supply. But, hmmm.

Then I saw the Mini2440. Also in the $100 department, it has a 405 MHz Samsung S3C2440A ARM920T chip, a 3.5″ touch screen display, 2MB NOR flash, 64MB SRAM, and 128MB NAND flash, Ethernet, USB, COM, audio out. It comes preinstalled with Linux 2.6.3 and a Qtopia graphics. There seems to be a version without the touch screen a bit cheaper here. And it appears to have a cheap camera available as well. And, oh yeah, it has 8‐channel 10 bit A/D converter with sample and hold, and a bunch of digital GPIOs (more info here). And here is a video of the GPIO at work. This sounds like an awesome system for PHY2PHY projects, it could be its own webcam and webcam display as well.

Tesseract OCR

If you need a free OCR program, try Tesseract. It is awesome!!! Skip GOCR.

No problems building it on OS X. One thing you may need to know is to use ImageMagick "convert" command with "-depth 8" to build TIFF files that Tesseract can read.

Saturday, June 05, 2010

Breath-over-IP redux

So honestly, my breath-over-IP project is not at cool as I want it to be. It actually an on/off system rather than a more "analog" transmission of breath speed.

The problem is that the anemometer impeller and the output fan both have too much inertia. The anemometer impeller is incredibly sensitive, but once it starts spinning it can take several seconds to stop, even without any breath. The fan is the same way, once you turn it off, it takes several seconds to spin down.

So I am contemplating redoing Breath-over-IP using a servo motor and servo controller. This should allow me to speed up and slow down the fan motor very quickly. On the breath sensor side, I could use a pressure sensor chip.

Finally, I'd like to solve my networking challenges using a plug based Linux PC with a USB-attached Arduino. That way I can do very complex networking in Python on the plug computer, and let the Arduino handle analog/digital I/O, which it does well.

So that's my plan...