peteg's blog - hacking - nixie clock - 2010 02 12 MoreHackery

Nixie clock update: hacking continues

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Well! It's been a long time since I wrote about this project. A lot has happened, even some good things. Hardware-wise I put the ts7260 beyond use by somehow trashing the onboard flash. All I did was ask it to write 6kb to the root filesystem! Instead it took out enough of Redboot (or perhaps one of the even more obeisant Technologic Systems boot loaders) that recovery became a matter of finding something with real serial ports, and trying my luck with the serial blaster utility that someone wrote for precisely this contingency. Suffice it to say I got far enough to know the board is not toast, but not as far as getting it working again.

I met up with Andrew T on Monday past and he gifted me with a pair of ts7250 boards, quite similar to the ts7260 but lacking the power supply magic; I must feed them 5v and nothing more. They both fired up fine, but with Linux systems too far out of date for my purposes. Fortunately their real-time clocks appear to work, and the world has regained its rosy tinge.

So I spent this last week, more off than on, building kernels and wireless drivers and whatnots for one of these boards, saving the other against calamity. It mostly works, albeit with some dodginess in connecting to the WiFi: the dhcp client in busybox takes a few goes to get a lease. I need it to reliably connect before I can cut the rats' nest of umbilical cords the ts7250 presently lives off.

Today I bought a Creative Sound Blaster Play! USB audio dongle. MSY is selling them for just $25, a steal for such an anachronistic device. (Creative itself wants $28 + $15 delivery.) Quality is fine to these non-discerning ears. It will take me a while to compile up all the ALSA libraries and things; I'm hoping to use MAD with an infra-red remote control.

Lesson of the day: say configure --prefix=$PREFIX yadda where $PREFIX is where the artefact will appear relative to the root of the destination filesystem, and say make DESTDIR=$DESTDIR yadda where $DESTDIR is the root of the destination filesystem on the host system. ALSA embeds absolute paths into the libraries. This approach screws up the paths in the .la files that libtool generates; it assumes that you'll be compiling relative to $PREFIX.

Software wise I hacked up a crossfader for the digits. It looks OK, but as Bernie observes it will certainly need tweaking to take care of the relative digit brightnesses and perhaps those amongst the tubes too.

I spent the final week of January in Orange. I helped Dad build a wooden case for the whole thing. It's not going to set any size or innovation records, but it looks tidy enough. I'll take a photo when the software is sorted out.