The circuit board of this clock is rather a work of art. Impressive. I recall an old professor of mine built something similar using two hard dive platters as the base. He skipped the seconds ring though, so his only had the two rings. Never saw the circuitry behind his clock, but I doubt it was a nice as this example.
Regarding the circuit board, I find it intellectually satisfying to see that he placed the date that he made the clock onto it (8/8/1970). How many times have you opened something up and asked, "I wonder when this was made?"
The beauty is on the inside. Although the wood case is handsome, I think this would be very nice in a case that allows a view of that amazing looking circuit board.
I love computers and programming, and that's pretty much what I do now. But years ago I was far more into electronics, and seeing schematics and old layouts is powerfully nostalgic (I can smell the solder). Building even simple devices with analog and basic digital electronics is incredibly fun and interesting, but also relaxing and a great solitary experience. Sitting in front of my laptop with IRC, Twitter and 30 chrome tabs open while hacking is a different experience than sitting at a garage bench with some old photocopied article/schematic from a magazine and a pile of parts.
They're different things, neither better than the other, but they both stoked this engineer's interests. I hope kids today are exposed to the electronics field like I was.
I hope kids today are exposed to the electronics field like I was.
It seems harder to me. Your past days are reminiscent of mine, but I could get on my bicycle as a sixth grader, bike to Radio Shack, and grab some parts (light-activated SCRs, transistors, timers (555!) and logic chips and make stuff. Sometimes I'd get a grab bag of 'unknown' digital pieces and try to figure out the pin-outs (always could rely on +5 and ground being standard).
I'm not sure how kids go about doing that today. I don't know of any store a kid can get to (without a credit card, that is) that has that kind of hobby equipment any more.
I recently had occasion to go through the house where I grew up (my father still owned it) and saw all of my old play stuff. I told my tale but the kids (teenagers now) didn't seem so impressed (old CRTs lying around!). I grabbed the old Radio Shack IC guidebook and left the rest behind. Quite a sad day, actually.
I live here too. I've never heard of that, though. Seems it's a little far for the kids to bike (from Marblehead). Maybe I should take them out there some day and see if anything "clicks." Thanks for the tip.
In grad school, my office had an ordinary Edison incandescent bulb, kept on 24/7. Being probability nerds, we kept statistics on when it burned out. We had been expecting something like an exponential, or a bathtub, but it was much closer to Gaussian, with a mean lifetime around 1 month and (rough) standard deviation on the order of a few days.
A Poisson variate always has mean = standard deviation. If these things lasted a month +- a few days, they couldn't be from a Poisson distribution.
(Or, with no calculation: The thing about a Poisson distribution is that it's what you get from a memoryless process. If the bulb almost always burns out within, say, a week of reaching 1 month, then it should also almost always burn out within a week of first being switched on. So its mean lifetime can't be much longer than the typical variation.)
It sounds to me more as if lifetime was proportional to some physical characteristic(s) of the bulb that were controlled in the manufacturing process. For instance, maybe lifetime was proportional to thickness of filament or something of the sort. (In which case, the vendors could have made the bulbs last longer, but perhaps only by also making them more expensive. Though it's tempting to speculate that they were designed not to last too long, so that you had to buy more.)
It fails when a certain proportion of the filament has evaporated.
The evaporation rate is pretty constant, assuming either a getter or large enough bulb that the evaporated tungsten doesn't change the environment.
So you would expect some form of bell curve distribution around the design lifetime.
Bath tub curves tend to come from large assemblies of reliable components
Yes, the results are consistent with that. Whatever stochastic effects there were, like electrical fluctuations or materials variations, were negligible.
It has switches and circuitry to set the time. Presumably he sets it for daylight savings changes, at the very least. And the page says it was turned off at least twice. It's not meant to keep a perfectly accurate count of time over 40+ years.
This was at the top of the front page of HN and HN classic. It doesn't even tangentially touch upon entrepreneurship, hacking, or startups. I won't rule out it being a honeypot of some kind, but maybe it's time to think about ways to halt the drift?
I'm quite new to HN and am just getting a feel for what's posted here. I did, however, just read the HN Guidelines recently to help figure it out. First two sentences on what to submit:
Anything that good hackers would find interesting. That includes more than hacking and startups.
Hacking is such a broad term. Is 14 hours of pounding on a keyboard writing algorithms hacking? Is circuit bending hacking? "Hack the Planet" hacking?
Personally, I visit Y Combinator for a wide range of topics - from entrepreneurship and start ups to "hacking" and technology. This seems to fall in the second half? Or, am I wrong?
If anything, I'd rather see more of this stuff on HN, the deeply interesting articles on wider ranging topics were what kept me coming back here in the first place.
This to me is the very definition of hacking. This is digital circuitry built from individual transistors in a age (1970) when almost all electronics were analog. Trust me, this guy was considered a hacker in those times.
Sure, today we could fit that entire circuit along with automatic daylight savings switchover in software into a single $2 chip, but that's not the point.
I was lucky enough to get started in electronics at the end of that era: in high school Radio Shack was still a useful resource. As an 11th grader I made circuit boards using a Sharpie, some press on decals for IC footprints and electrical tape cut into strips to mark where circuit traces would go.
Today, I'd fire up a freeware or open-source CAD program, email the output files to some PCB house in China or Bulgaria, and get back professional quality boards a few days later for $50. A far cry from screwing around with smelly chemicals in the sink and pissing my mom off with the stains it left behind.
You need to know where you came from to appreciate where you're going!
