Wednesday, 28 September 2011

PoE Network controlled signage

I may have a requirement for several 'remote controlled' illuminated signs. (where remote could be network driven) - These aren't Scrolling LED 'calls in queue' type ones, but more the warning 'Laser on', 'Mic Live', 'Conveyor Running' type ones.

Normally these things seem to be driven directly from some local switchgear or output, but what if you want to gather status centrally , or illuminate the sign depending on some remote sensor (be it a web tsunami alert or the boss' car being picked up on the ANPR at the gate)

Cue a quick hacky prototype: Take one nanode and use the digital outputs to drive a mosfet to switch some cheap LED strips from IKEA. So far so good, but that requires a 12v (since thats what the strips use) supply. The nanode can take that on the screw inputs if you add a heatsink to the reguator, but I'd rather get rid of the PSU alltogether: cue a cheapo 802.3af PoE splitter from TP-Link, and I have the whole lot driveable off one RJ45 cable.

Onwards to software, and it looks like bitlash / restuino look useful (esp if I get the whole lot working with DHCP too).

Anyway, with a range of lighting areas possible (thanks to addressable outputs on the nanode) per display, the option to have a nice facia with multiple 'zones' illuminated is possible. Now to find a nice case...

Thursday, 1 September 2011

puppet /. facter / v12n

As I'm starting to get into puppet, especially when used with the foreman for dashboard display, I've started noticing a few (fixable) oddities

1st up ios that not all RHEL clones are treated equally -- some patches are just adding detection and flaggin, others go the full hog and make sure its in all the "constrain:" sections in facter too. I guess I need to do a code review and pull in the extras. Cue lots of different VMs
(the joys of a weeks home leave from work..)

secondly, virtualisation detection is 'flakey' -- some (vmware) are really well detected, but new kernels give false positives (see issue #7723) so I'm going to set about tidying these up and adding hyper-V detection properly