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Showing posts from 2013

Low-Level hardware hacking

In our 3 shiny new computer rooms (supercompute, IO, Tape - Each with slightly different environmental and cooling requirements), the architects have fitted a single temperature sensor on the back wall. Out of the airflow. This isn't giving us a terribly accurate picture of the supply air going into each rack, and so an alternative DIY method is underway.

A Raspberry Pi in each room (small, low enough power that it can be fed from PoE via a splitter) acts as the local 'head' and grabs the data to send it to a central message broker. From there, we can choose what to do and how to display it.

The sensor hardware consists of: A single DHT22 attached near to the Pi - As useful as these are on an arduino, on a R-Pi they are a bit harder due to the need for timing. The Adafruit interface for these grabs directly from memory address and seems well, a bit hacky. As suggested on IRC, a proper kernel module may be helpful. hint for someone else to complete :-)

The main sensor array…

Internal Gravatar type service

Since arriving at my new job (excellent ta, thanks for asking) I've once again come across some internal pages that it'd be nice to associate mugshots with (thumbnail is fine) in a service just like gravatar offer. In fact, exactly like gravatar offer... then it could be used with some minimal URL re-writing and minor code changes in applications
IMHO when you have a corporate photo-id upon your person, then this should be available on the intranet - it shouldn't be *that* hard to use the same algorithm on a small webserver vhost to select a suitably sized photo (since its corporate, these can be mapped automatically to LDAP or some other identity management service) entries.
Perhaps I'll have a code, but not next week as we have new toys arriving from our vendor (rhymes with  'play') finally :-)

qlock something clone

Much as I like the design of the qlock two, I really can't ever justify the price of buying one. Although there are designs for clones on instructables.com, I'm going to rework the design using addressable RGB strips rather than individual white LEDs - it means there's more work in the woodwork of the casing (to prevent bleeding to adjacent cells) but should provide for nicer coloring - being able to fade in the current time from the background colour (which will be hooked to the house MQTT feed for things like power / temperature etc) Oh, and it'll be NTP synced.

Not sure what I'll use as the main controller yet - possibly a R-Pi as its a bit more flexible than the standard arduino. Anyway, once I've worked out the pitch, it's time to learn vcarve down at the local hackerspace.