I made a first try at the top half of the case. I was hoping I could make a rough model for the form factor from MDF, but the MDF basically fell apart already during machining and I had to cut more things than planned manually. The not so pretty result is here:
http://downloads.qi-hardware.com/people/werner/anelok/tmp/mdf-start.jpg The "sunken" wheel is probably caused by untrimmed MDF fibers pushing the PCB away from the border on which it should rest. The holes for OLED and LED wouldn't exist in the real case - I'd just use transparent acrylic for the whole piece. Alas, I don't have acrylic of the right thickness at hand, so this will have to wait until later this week. This is what it should look like: http://downloads.qi-hardware.com/people/werner/anelok/tmp/top-mesh.png If anyone wants to play with the mesh: http://downloads.qi-hardware.com/people/werner/anelok/tmp/top-mesh.stl.bz2 Last but not least, I wrote a first test for the hardware random number generator in the transceiver. This will be the system's main if not only source of entropy, so it's important that the RNG works flawlessly. Getting the RNG in a crypto system wrong is what earns you this kind of press coverage: http://arstechnica.com/security/2013/09/fatal-crypto-flaw-in-some-government-certified-smartcards-makes-forgery-a-snap/ My test wasn't quite so exacting. I just pulled seven bits from the RNG, used them as index for a "bin", and then displayed the bins and the number of times they've been chosen on the OLED, repeating the operation until one bin was about to reach 64 and thus leave the 128 x 64 display. One result is here: http://downloads.qi-hardware.com/people/werner/anelok/tmp/mdf-rng.jpg At a first glance, the result looks reasonable: all the bins fill up to some extent, some faster, some slower, and there are no extreme outliers. The pattern also changes from run to run. Of course, this needs much more analysis, but it's encouraging that the random numbers do indeed appear to be random. - Werner _______________________________________________ Qi Hardware Discussion List Mail to list (members only): [email protected] Subscribe or Unsubscribe: http://lists.en.qi-hardware.com/mailman/listinfo/discussion
