Very nice! Thanks for sharing.
On Thu, Jul 17, 2014 at 1:23 PM, [email protected] < [email protected]> wrote: > Here's a not-so-good picture. Basically the NE2's simulate the large & > small hands of a traditional mechanical clock, and the outer digits are > nixie tubes. The NE2's are grouped into 36 'rays'. Each ray represents 100 > seconds for a minutes-hand, or 20 minutes for the hours hand. The hours > hand is shorter, so the rays are split into inner-rays (for the hours and > minutes hands), and outer-rays (for the minutes-hand only). Towards the > center, the innermost bulb is shared between adjacent rays, because you can > make a smaller circle with 18 bulbs than you can with 36 bulbs. 36rays * 8 > bulbs per ray = 288 bulbs. Then an additional 18 for the center = 306 > bulbs, which means 306 dropping resistors. Yes I had fun soldering this. > > Each ray is driven by an opto-triac, which applies AC to the bulbs so both > electrodes glow. If I used transistor drivers, it would require DC and > therefore only a single electrode would glow. Not only does this reduce > brightness, it probably reduces lifetime. The 72 opto-triacs are driven by > TTL latches (74LV374), and they are connected in series to reduce PCB and > cable wiring. This in-turn is controlled by an FPGA, which sends the > light-bulb information serially at about 1 Mhz when the AC-line-voltage is > around zero volts. If I did not do this, there would be streaking of other > rays. The FPGA monitors the AC-line to know when the zero-cross occurs, and > also uses it as the time-base. > > Although I developed a PCB for this, I dont intend to sell / give-away the > design because I dont have the time to support it. It would take away from > my time I want to spend on other projects. > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web, visit > https://groups.google.com/d/msgid/neonixie-l/caa7a0e6-975d-4fc3-b7ad-b058bac56dcd%40googlegroups.com > <https://groups.google.com/d/msgid/neonixie-l/caa7a0e6-975d-4fc3-b7ad-b058bac56dcd%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/CAOX%2BRHLjDQNzGRUvj-86YyOP_dGr-j%3Dtss9HiJoc8f%3DDe0-1uQ%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
