torsdag den 13. marts 2008

LCD Display

I'm now working on adding an LCD display to my Gumstix. Not the 4.3" Samsung display from, but a smaller 128x64 monochrome display from SparkFun Electronics. So why not a superfancy color display? Because the monochrome display uses only about 3.5mA @ 5V = 17.5mW (without background light). I'm connecting the display to an Atmel AtMega16, and communication between the Gumstix and the AtMega is done using a serial connection. I could have connected the display more or less directly to the Gumstix, but I would have needed some kind of level conversion (Gumstix @ 3.3V, LCD display @ 5V) for 14 IO lines, and any error in the connection might fry the Gumstix. So I decided that a serial connection would be much easier to get right, and if I fried the AtMega it would be pretty cheap to replace.
Later I'm going to add temperature sensors to measure the temperature in the different rooms in our house, and outside too.

søndag den 10. februar 2008

libbluetooth blues ;-)

I had trouble getting the obex_test program to work with bluetooth.The fault was that the bluetooth include files and library is located in $(STAGING_DIR)/usr/include and $(STAGING_DIR)/usr/lib. Openobex expects them to be in $(STAGING_DIR)/include and $(STAGING_DIR)/lib. Note to self: Change the destination path (in bluez or in openobex ?).

torsdag den 7. februar 2008

amixer problem + solution

To get amixer to work, libasound needs the alsa.conf configuration file. In the default gumstix buildroot for alsa-lib, the configure option --datadir=$(STAGING_DIR)/usr/share must be changed to ie.: --datadir=/usr/share, otherwise it tries to read the alsa.conf from the staging-dir, which is of cause not present on the gumstix. alsa.conf needs to be copied to /usr/share/alsa.conf.

fredag den 18. januar 2008

Internet radio

So I wanted audio for my Gumstix Verdex, but I've already used the expansion ports for other cards. So I got a USB sound "card", a Hercules Muse Pocket LT. It works out of the box with the snd-usb-audio kernel module, and I can now listen to internet radio with eg:
wget -O - http://some-mp3-stream-url | ./madplay -