I love old meters. Now, if you could only include one of these CRT meters. My dad's old HiFi (to all you youngsters - that's what they called "iPods" back then) had a round one that displayed on the end of the tube.
My current office clock is a mirror image clock. Partly because it's on the wall behind me and I can read it better reflected in my window, and partly because it throws people off. People are used to it now though, so I need to find some other form of equally confusing time piece.
I have a RTC Pmod that could be the start of some sort of clock. I need to make something that doesn't require a lot of mechanical or woodworking skill though.
Maybe just a simple binary clock would do the trick. Or, maybe something with Neopixels.
@Max, I am a hoarder and I also have a soft spot for analog meters, but you take the cake there!
I'd keep it simple I think. I love the idea of using a metronome-type meter to tick the seconds. I was going to suggest a centre-zero meter (I might even have one for you if you want) but really if you're going to drive them with an MCU then you can make them do what you want anyway, and centre zero meters need + and - drive voltages which would make life difficult.
I'd imagine you are going to drive the meters with PWM at a frequency which won't show on the meter ballistics? I'd stick to a maximum of 12 things on a meter (in this case hours) because otherwise you'll have to get very close to read them easily. Are you going to make custom scales for them?
@David: I was going to suggest a centre-zero meter (I might even have one for you if you want)...
That's very kind of you, but I picked a couple up as part of my "stash" -- now I'm trying to worjk out how to use them. The thing is that, using the MCU to drive it, I can make a regulat meter "look" like a center-zero meter...
@David: I'd imagine you are going to drive the meters with PWM at a frequency which won't show on the meter ballistics?
That's right -- PWM is the way to go -- in fact I'll be writing a blog on this in a couple of weeks -- explaining how you work with different meters that were originally intended to display voltage, current, resistance -- and different orders of magnitude -- and so forth...
@David: I'd stick to a maximum of 12 things on a meter (in this case hours) because otherwise you'll have to get very close to read them easily.
This is something I'm going to have to look at -- in the case on minutes and seconds I'll need to go up to sixty -- but I might have major lines on the graticule every 10 units with minor lines betweeen them for every unit.
@David: ...270 degree meters [...] any of those in your stash?
I think there are a couple, but the ones I'm using for Mins and Secs are a semi-matched pair (same manufacturer and same look and feel - -just one was originally intended for volt sand one for current -- but I'll be replacing the legends on the faceplates anyway).
The ones I have have a 90 degree movement -- and that will be OK for 6 major marks with 10 smaller ones between them.
@Rcurl: I was soooo disappointed to have missed the Hamfest this year- although it sounds like you made off with all of the choice stuff before I could have gotten there anyway.
I wish you coudl have been there with me -- both ouf us sporting our Hawaiian shirts (truth to tell, there were actually quite a few folks with Hawaiian shirts there ... but mine was the best LOL). Wait till you see my photos -- there were three vendors selling meters -- more meters than you can possibly believe -- I really only got a relatively small number compared to all the ones that were out there.
@Rcurl: Next year I wonder if they would let me in if I ride an electric scooter with a small trailer behind!
One guy had a weird low-down trolly with a high-up pushing handle that was ideal for thsi sort of thing. Wait till you see my pictures (hopefully in a blog tomorrow) -- I want to get me one of those!!!
Hey -- fancy a road trip up to Dayton Ohio next May -- apparently they have a MONSTER Hamfest (I will talk about this in my Hamfest blog also)
Talked to my friend Joe; he and his wife are going, and haven't missed ONE in at least 20 years! They did warn that you need to make hotel reservations NOW as this is one of the major annual events at the convention center! I made mine today, and there were few rooms left (at this hotel), and rates of course are high. Anywhere in the airport area works well; if you wait, you may have to stay in Cleveland!
BTW, my wife is THRILLED at the idea! Looking forward to the USAF museum etc.
I think the IT guys have disabled links in comments due to spaming -- can you post the contact details for the hotel -- also what dates are the Hamfest? I was thinking that we could all drive up on Wed -- go on a museum tour (to be organized by Antedeluvian) on Thur -- and got to the Hamfest on Fri and Sat -- then drive back on Sun
Hamfest site is hamvention.org. Dates for 2015 are May 15-17. We are at the Quality Inn Suites. On Maxton Rd, is a solid mile of hotels and restaurants near the airport and convention center. Currently reserved for Fri-Sun but could modify easily. Joe and his wife (same schedule as us for now) likely not interested in the tour as they have been going since before they rename the Hamvention!
I spent a day and a half at the National Museum of the USAF, then went back and spent another two days. If you are going to spend only one day, check their web site first so you don't miss something. Although if you make Dayton an annual event, you can go back to the museum each year also. When I was there, they had just received the Hexagon KH-9 spy satellite, so there is always something arriving.
@David: I was going to suggest a centre-zero meter (I might even have one for you if you want) but really if you're going to drive them with an MCU then you can make them do what you want anyway, and centre zero meters need + and - drive voltages which would make life difficult.
I was thinking the same thing. I don't think it will be difficult at all to drive a zero-center meter from a single power supply, though. Just put a big electrolytic capacitor in series with the meter movement.
To go along with it, maybe synthesize a "tick" when it flicks left and a "tock" when it flicks right.
Interesting idea, will be nice to see the finished project. Maybe you could find an old GC-1195 (Heathkit clock) on ebay and salvage the "Big Ben" chimes synthesizer board as well as the tic toc. Or build your own Big Ben sound generator.
@David: ....or get one of those old "ding-dong" doorbells and fire it up on the hour....
I'm thinking more like on the hour you hear the sound of creaky clockwork turning, and things sliding and graunching and suchlike -- something that goes on and on -- then cumulates in a soft, sweet "ping"
Personally I'd go with keeping it simple and make it so the dials are easy to read but make the dial look aged.
The sound selection for the tick..tock would depend on the responsiveness of the selected meter. A slow response might work better with the sound of a larger clock while a faster response might work better with that of a smaller clock or watch.
They way I understand it you apply 6 volts to the heater and after 60 seconds the relay closes and disconnects the heater which cools down. The heater then reconnects and starts the process all over again. Your time measurement would then be retro too and you'd have a neat vacuum tube to show off. Of course it would only tick every minute instead of every second.
@DrFPGA If you pre-heated it to the right temp could you get it to switch every second?
Probably not. We're talking about something thermal that probably needs a large piece of hysteresis between the heating turn on and cooling to turn off. If you kept it heated up it would never turn off. You would need to use a higher voltage which might damage the tube or you could control an external heater to increase the rate of heating that shuts off when the relay goes on.
Reading Max's article again, it probably doesn't fit into his Vetinari Clock concept. It just the way my brain segways. I would use the relay to trigger the up/down counter on a 64 tap digital pot like the AD5113 and use a comparator to reset the pot when it hits 60. The comparator would trigger another digital pot that resets at 24 or 12. An all analog solution with no programming.
@ GSKrasle Could you build a PLL with the relay cycling as input, and take a multiplied output frequency?
Imagine how many hours that would take to lock. You have a VCO generating about a 1sec output that gets knocked down to 1 minute pulses to be compared to the signal from the relay. The phase error is then used to adjust the VCO frequency until the error is really small. You'd need lots of 1 minute pulses for the loop to do it's thing and sync the VCO to the relay.
How about doing the whole thing analog? Each meter can be driven from a timebase like an oscilloscope or analog computer. You can sync between them the same way the horizontal and vertical waveforms are synced in an analog TV, but with more stages. And then sync the whole thing to 50/60 Hz line frequency to keep accurate time.
I built an analog timeofdayometer. See picture below. Accuracy was a bigger issue than I originally imagined due to the following. I was using a long-throw movement, which have a not so constant-force springs. I tried to copy the non-linear scale of the original faceplate but that was a challange to layout (I used AutoCAD) and I never really got it right. On my next iteration Im going to use a linear scale and apply a nonlinear correction factor on my output value. Another issue was that, although I used a 32.768KHz xtal timebase, my time would drift. I used buttons in the back to set the time but next time I'm just going to throw in a GPS to get the time and forgo buttons and solve the drift problem at the same time. I tried the flicker thing and it looks cool. I only flickered the needle every 15s so it wasn't annoying.
@HeyJoe: ...On my next iteration Im going to use a linear scale and apply a nonlinear correction factor on my output value.
That's something I might be doing -- alternatively, for some ptojects I might want a non-linear scale that doesn;t match the non-linerarity of the meter. In thsi case I might use a look-up table approach and then interpolate between table values.
I like your siolution of displaying hours 1-6 and then 7-12 with minutes inbetween.
Another solution might be to have a "rest" position on the left and then hours 1-12 and minutes 1-60 shown as concentric scales. The needle could start off in the "rest" position -- then move to indicate the hour -- then move to indicate the minute -- then return to the rest position...
32768's are a peeve of mine, and their history is illuminating.
The value was chosen (1970s?) for its obvious ease in converting to integral seconds, but it is difficult to get that value in the type of 'cut' that gets the best thermal stability ('A-T'), so a less-stable (and very small) one was used ('Tuning-Fork'). And hey! the thermal drift didn't even matter! if you have a reasonable-quality watch, look at the back. It's metal, isn't it? The front has an air-gap, and is therefore thermally-insulated. What is the temperature of the workings while the watch is securely strapped to your wrist? Pretty close to 37°, eh?
Now take that tried-and-true ol' reliable crystal and put it in a desk clock, and thermal drift might surprize you.
Another interesting property of the 32K tuning forks: their frequency vs. temperature curve is a parabols, with the peak right at 37C! Your wrist is the oven..... also explains why a (properly trimmed) watch will lose time when off your wrist.
Yeah, parabolic. A-T is third-order. For both, cut angles can select the curve parms, making the field wonderfully complicated. I used to have a booklet from Fox with some details, but can't find it; things like using crystals in series to get compensation, DC bias effects, good stuff.
Hi Max, My first boss at London Underground Research Labaoratory made a clock with meters for telling the time. I think it was all run with TTL 74 series IC's on veroboard.
However I think you are missing one dial which of course has to be a sun dial.
How cool to have a sun dial that works at night. Not sure how it would be achieved obviously the gnomon and dial are easy, but casting the shadow would require a led light source and stepper motor? Or would you use a fixed light source and turn the dial?
I think this might just end up on my whacky to do list.
Great article and look forward to further updates.
@Crusty...GREAT idea. You could have a curved line of RGB LEDs some distance above the sundial to simulate the sun, clear ones that have a narrow beam. and illuminate them one at a time, changing every 10 minutes or so (this implies 72 LEDs for 12 hours) and use one colour for day and another for night. Wouldn't need any motors, just some electronics to drive the LEDS. Since your LEDs would be fixed you wouldn't need to compensate for the seasons either...
Is that your "secret ingredient" to go up top center? It's the very first thing I thought of. I actually used one in a circuit back in the '50s; possibly entombed in my basement still! If I'm right, sorry to spoil the surprise; if not, think about adding one! Think 6E5.
@mhrackin I actually used one in a circuit back in the '50s; possibly entombed in my basement still! ... Think 6E5.
Just a few days ago after watching Star Wars Episode IV for the umpteenth time I suddenly realized that one of the props was a highly-magnified magic eye tube of the 6E5 type, poised to resemble a radar screen.
I won't spoil it just yet, so if you have the DVD can you spot it? First to report back gets an attoperson award, which is equivalent to 1000e-6 persons.
Hint so you won't have to watch the whole thing: It is somewhere on Uncle Owen's Farm.
If you're really into ancient uses of ancient technology in TV, check out the opening credits for "The Twilight Zone." I vaguely recall some oscilloscope traces of audio... along with some Theremin music.
Neat project! I've lived more in the digital realm than the analog, so I'm curious how you're planning to drive these meters. Do you have the voltage and current specs for each? I imagine they'll require more power than a microcontroller output could provide so I'll have to stay tuned for the next report to learn how you plan to do that.
@Clarke: ...Do you have the voltage and current specs for each? I imagine they'll require more power than a microcontroller output could provide...
That's one of the problems in that you usually can't find any documentation for the meters. Also you often end up modifying them by removing shunt or series resistors. Also you have to be careful measuring the internal resistance -- in some cases you can "blow up" the meter using (trying to use) a multimeter to determine the resistance.
In some cases like a meter that's geared to to measuring say 10mA max, you could drive this directly from the MCU output -- but you also have to remember that the meter itself can generate negative voltages due to reverse/back EMF. Personally, I prefer to use the MCU output to drive a transistorm and have the transistor drive the meter -- all of this will be covered in my forthcoming blog.
Max, this is going to be an awesome project - one where I think everybody will get the juxtaposition of old and new tech.
I still think that making it "dead on" accurate using a GPS time source would be pretty cool - "I'll just sync my pocket watch with atomic clocks orbiting the earth, using my steam-punk analogue meter clock".
Maybe make the seconds tick inconsistently, but have it bang-on when the seconds hand goes from full scale back to zero.
It would be perfectly reasonable to sell these, or kits, or partial kits. You could even sell the design/code, either to DIYers or to somebody like 'Spirit of St. Louis' (Look them up: linkage is disableized here).
I have several of their things, and they're cool, except a little flimsy (the paper scale on the pop-up dial for the alarm-clock peels, and the bank of mechanically-linked switches [and the antenna] is broken on the CD Boom Box). But the 'Field Telephone' is the only reason I still have a land-line.
@GSKrasle: Just use something like a tack hammer and record the sound. I suspect some of the other (eerie) effects can be found on the internet in appropriate formats.
I'll be more than happy to make any plans and any code freely available. I'm already planning a blog on how to control the meters from the MCU (in general terms) -- then later blogs can have the code I use for the clock.
One thing you have made me think about is that the code should be written in such a way as to facilitate swapping one meter for another (this might be trickier than you think if the meters have a non-linear resoponse ... hmm, food for thought :-)
@Tloose: Use a solenoid to strike the inside of the wooden box to make an authentic sound...
That's not a bad idea -- but I also want to have other sounds, like on the hour the sound of (rusty) clockwork graunching and straining and then letting loose with a release sound as the hour meter flips over to the next hour...
Well, if you're going to use an audio format (mp3 etc) you could STILL use the box. Just use something like a tack hammer and record the sound. I suspect some of the other (eerie) effects can be found on the internet in appropriate formats. Some folks use these for ring tones!
@mhrackin: Are you on your way to dinner in Brazil?
I'm literally poised to walk out of the door -- I'm going out with a couple of the conference organizers to a Brazilian Steakhouse called Fogo de Chao – I looked it up on the web (it might be a chain) and the food sounds fantastic (www-DOT-fogodechao-DOT-com-DOT-br)
@mhrackin: They're about the top of the food chain price-wise but excellent food. Hope you're REALLY hungry!
I am REALLY hungry ... now (armed with your info), I'm hoping that someone else picks up the bill LOL
PS I've been looking at their online menu -- I'm drooling over my keyboad -- I hope you can get smaller portions of multiple types of meat, because I'm soooo tempted by the picahna, cordeiro, and linguica (to name but a few)!
As I'm sure that you know from personal experience by now, you can have as much or as little as you wish of EVERYTHING. The philosophy of churrascaria is no concept of too much. YOU control the serving by means of a disc with RED on one side, GREEN on the other. Green means feed me, red means no more (for now; you can flip back to green anytime.
I know what you mean. I sometimes use it to translate into German just to give my Teutonic friends a good chuckle! It realy doesn't do well with idioms in either direction. But for short simple things like your 3-word motto it'll be close
Speaking of ancient TV, at the opening of one episode of the Ernie Kovacs Show he kicks over a can of white paint which spills into a line at the edge of the stage. I'm not sure of the exact sequence, but the white line turns into an oscilloscpe trace of an audio tone, and he then puts his hands at each end of the trace and moves his hands together and back apart, changing the frequence of the tone as he does so. The man was genius!
Sidelight on wire recorders: those were standard-issue for the CIA (and their competition) WELL into the 1970s because they were 1) much more rugged and impervious to damage and 2) non-editable unlike the "new-fangled" tape ones! All Uhers.
Max, you have better luck than the Irish! I searched YouTube for Ernie Kovacs Show and this one came up first. It's bits from several shows, with a great 1812 Overture. The Oscilloscope trace comes in at about 6:03 minutes.
Hmm; OK, let's try another way to skin this cat. I wonder if Pig Latin will get by the URL-ay Ilter-fay?
As one who remembers watching ALL his shows when they were "first run" (and on a 12-inch round-screen Zenith TV with rabbit ears at that, B&W of course), Kovacs was a true master at getting around the very strict TV censorship of the '50s. Most of the time, they didn't even realize what he had done! He was the primary force that eventually led to the overthrow of the "Hays Commission" that set up the censorship rules Lenny Bruce and later George Carlin finished the job. BTW, I think the beauty who had the "bunter" line was his wife, Edie Adams! Kovacs' untimely death in 1962 deprived us all of one of the greatest comedic talents ever.
PS: a few years after we got that Zenith, it got to the point where (at age 10 or so) I couldn't keep it running with tube changes; I salvaged most of the parts (including a huge multi-voltage output power supply separate from the main chassis) and it served as the source of my first basement "junk box" parts inventory. The PSU was used to power several different tube designs for audio, ham gear, etc.
Well, you better get that torch (and the cigar per Stargzer) under cover. I was jsut checking out the ATL weather radar, and I see a nasty thunderstorm drawing a bead on Huntsville.... coming from the west-northwest.
He'd also thump the floor with his hand, creating a nice random audio pattern on the 'scope trace. Brilliant! This was an early "blue screen" effect, except it was B&W so you had to key on intensity level instead of color. Kovacs sometimes superposed himself in clips from movies, wearing a white coat and white cap so his black hair wouldn't be transparent.
Here's my favorite Ernie Kovacs TV story: In the old Dumont Network days, the studio was on top of a hill with a great view of the city (don't know which one). Kovacs and his buddies liked to play a little game during the late night movie. While it was playing, they'd lower the master volume at the station. Everyone watching the movie in TV Land would then turn up the volume on their sets. Kovacs would do it again, slowly lowering the master volume over half an hour or so until everybody in TV Land had their volume cranked up all the way. Then they'd raise the master volume back to full strength and run to the windows. Lights would come on all over town as people were awakened by suddenly-blaring TVs.
You could get away with that sort of thing back then because TV was so unreliable that people didn't suspect it was deliberate.
@betajet: Here's my favorite Ernie Kovacs TV story:
In one of the retrospectives I saw Kovacs played a magician whose assistant brought out a double-shot for him to drink between each trick. That narrator of the special said that in rehearsal it was a double-shot of tea, but in live broadcast the stage crew substituted real booze. As the narrator said, you can see his eyes light up when he realizes that the first one was real, and then trying to count how many he had to go through before the sketch was over.
Again, probably something you might not get away with today, Andy Kaufman notwithstanding.
I think the original white line 'scope trace sketch went on longer that in the link. And did you see the two light bulbs and the empty lamp at the beginning of this one?
But the worst of all was the Network, who ran out of video tape and started recording over some of Kovacs' material after he died. His widow had to buy as many of the tapes that were left to preserve them as she could afford to.
Stargzer wrote: ... in live broadcast the stage crew substituted real booze.
I love live television. This sounds like the time Kovacs was playing "Percy Dovetonsils, Poet Laureate" and the crew put a goldfish in his prop martini. Percy wore joke eyeglasses, so he couldn't see anything and didn't notice until he started drinking: "Thomeone theems to have put a fishie in my martini." You can hear the crew cracking up. Kovacs never went out of character -- what a pro.
Wikipedia has a good article with other Percy amusements: en.wikipedia.org/wiki/Percy_Dovetonsils
That's awful about the network recyling his tapes. Just awful.
Used to work standby for the Old PBS pledge breaks. Close as llive as one could get in the modern times. (apart from this was 20 years ago. so I guess it is still Ancient.) The station manager would say that sports and pledge breaks were the only place where something unexpected could happen. The news being scripted.
Did get a bomb threat on the live phone once. Caller said there is a Bomb under your desk, then hung up. I had the composure to remain calm. During the show the managers did a cursory look under the stage. Usually things were much more mundane. Red Dwarf and Doctor Who were popular at the time. So our costumes would spout things from the show. Like us all wearing Holographic H on our foreheads.
It always surprised me that people really did call in and give credit information over the phone. This sort of ended when Cable expanded and fewer people used Over the air antenna.
Now we get live web webfeeds from things like the Iceland #Bardarbubga volcano. Can not seem to stop watching it.
Whenever wire recorder is mentioned I always remember a very old Letter to the Editor in Popular Electronics where someone asked if it was possible to convert a wire recorder to tape. The answer was, "Short of being brutal about it ... " followed by a cartoon of a guy at an anvil hammering wire flat.