Topic: Ahmed Mohamed's clock was invented and built by Radio Shack in the 1970s
Metæ started this discussion 11 years ago #45,721
http://blogs.artvoice.com/techvoice/2015/09/17/reverse-engineering-ahmed-mohameds-clock-and-ourselves/Somehow to me this makes the teachers and police seem even more retarded.
Syntax,what do you think? After all you personally designed both the Micronta 12/24hr clock circuit and the Vaultz™ locking pencil case.
Anonymous B joined in and replied with this 11 years ago, 19 minutes later[^] [v] #603,173
Metæ (OP) replied with this 11 years ago, 7 minutes later, 27 minutes after the original post[^] [v] #603,177
@previous (B)
The teacher was going to throw herself on the fake clock fake hoax bomb to save the children from the blast in a selfless heroic act of bravery.
The teacher was going to throw herself on the fake clock fake hoax bomb to save the children from the blast in a selfless heroic act of bravery.
Syntax joined in and replied with this 11 years ago, 1 hour later, 2 hours after the original post[^] [v] #603,227
1st how come becky is not on board re suing the teachers and Admin for gross Stupidity? And is there not some case worth lots of money for slander of the rag head kid? Also how dare that kid not wear such?Looking up just who holds the patents to alarm clock (The first seven segment digital clock!! US1289371) Patented: Dec 31, 1918
> Mohamed's clock was invented and built by Radio Shack in the 1970s
Radio Shack clearly did not invent the clock
Eye only once built a Clock - did not call it such - It was a digital counter - it used Vacuum tubes called Nixie's - When put together with lots n lots of time n parts I may have tested it at 60 HZ which wood have made it a regular clock - eye forget if I did that - Built it to measure RF stuff - Wayyyyyy to much work for the results.
Kid did not really do much of anything but will end up with lots of Scholarships and trips and fame for just deconstruction of a Radio Shack hunk of junk. We should all be Jelly.
Metæ (OP) replied with this 11 years ago, 48 minutes later, 2 hours after the original post[^] [v] #603,243
@previous (Syntax)
Did Mohammed's clock use a quartz oscillator or 60Hz line frequency for timekeeping?
Re: 60Hz line frequency I have a few synchronous motor clocks and continue to be amazed by such: cheap motor and a few gears — 1930s technology dead simple and perfect accuracy except for blackouts.
Did Mohammed's clock use a quartz oscillator or 60Hz line frequency for timekeeping?
Re: 60Hz line frequency I have a few synchronous motor clocks and continue to be amazed by such: cheap motor and a few gears — 1930s technology dead simple and perfect accuracy except for blackouts.
Syntax replied with this 11 years ago, 16 minutes later, 3 hours after the original post[^] [v] #603,248
@previous (Metæ)
Wood probably take a while to find the detailed schematic to that clock.
Betting as you wood its synced to the 60 Hz line. I think Hammond of Hammond organ fame invented the basic synchronous motor for the first accurate line clock, but its only a guess from memory and will look up later.
Wood probably take a while to find the detailed schematic to that clock.
Betting as you wood its synced to the 60 Hz line. I think Hammond of Hammond organ fame invented the basic synchronous motor for the first accurate line clock, but its only a guess from memory and will look up later.
Metæ (OP) replied with this 11 years ago, 2 minutes later, 3 hours after the original post[^] [v] #603,250
@previous (Syntax)
If it did use 60Hz line frequency, how wood the 9v battery backup work? Wood such drive a 60Hz oscillator to keep time going until mains power returned?
If it did use 60Hz line frequency, how wood the 9v battery backup work? Wood such drive a 60Hz oscillator to keep time going until mains power returned?
Syntax replied with this 11 years ago, 12 minutes later, 3 hours after the original post[^] [v] #603,253
@previous (Metæ)
How soon I forgot the battery in that bomb the kid made.
Cost wise it has to be a quartz crystal - Also from memory just guessing the accuracy of that clock running on the quartz wood NOT be as accurate as the line frequency itself.
Perhaps at a constant air conditioned house temp it wood be the same as line accuracy.
How soon I forgot the battery in that bomb the kid made.
Cost wise it has to be a quartz crystal - Also from memory just guessing the accuracy of that clock running on the quartz wood NOT be as accurate as the line frequency itself.
Perhaps at a constant air conditioned house temp it wood be the same as line accuracy.
squeegee joined in and replied with this 11 years ago, 1 hour later, 4 hours after the original post[^] [v] #603,273
@previous (Syntax)
actually quarts clocks are orderes of magnitude more accurate than a 60hz synchronous motor. you get 60 cycles, and that your period. quarts clocks have a period in the tens of thousands.
even the cheapest quarts jobs are more accurate than any electric or mechanical system. we went from super high end mechanical (vaccuum chambered) ingvar pendulum clocks, to quartz, to atomic.
pretty much line accuracy has never even achieved the precision of a floating balance mechanical clock (re: cheap mechanism) and so electric clocks have never been used as a standard time keeper like atomic clocks and the old navy ingvar pendulum clocks.
electric clocks were just super cheap and equivalently as accurate as a standard pendulum clock with a rate of 3600 beats per hour. or maybe it's that they are only one order of magnitude more accurate. but never more than that.
actually quarts clocks are orderes of magnitude more accurate than a 60hz synchronous motor. you get 60 cycles, and that your period. quarts clocks have a period in the tens of thousands.
even the cheapest quarts jobs are more accurate than any electric or mechanical system. we went from super high end mechanical (vaccuum chambered) ingvar pendulum clocks, to quartz, to atomic.
pretty much line accuracy has never even achieved the precision of a floating balance mechanical clock (re: cheap mechanism) and so electric clocks have never been used as a standard time keeper like atomic clocks and the old navy ingvar pendulum clocks.
electric clocks were just super cheap and equivalently as accurate as a standard pendulum clock with a rate of 3600 beats per hour. or maybe it's that they are only one order of magnitude more accurate. but never more than that.
(Edited 3 minutes later.)
Anonymous E joined in and replied with this 11 years ago, 11 minutes later, 4 hours after the original post[^] [v] #603,278
@603,250 (Metæ)
> If it did use 60Hz line frequency, how wood the 9v battery backup work?
I know I've had bedside clock radios that ran off the wall voltage and used a 9v battery backup, so I assume it's possible.
> If it did use 60Hz line frequency, how wood the 9v battery backup work?
I know I've had bedside clock radios that ran off the wall voltage and used a 9v battery backup, so I assume it's possible.
squeegee replied with this 11 years ago, 29 seconds later, 4 hours after the original post[^] [v] #603,280
so a synchronous motor has a rate of 216,000 based on 60hz (60 cycles per second)
a quarts clock has a frequency of 32,000+ hz and oscillates at 215 cycles per second. they lose less than half a second a day.
temp variations will not let a quartz deviate anywhere near as much as the absolute attainable accuracy of a synchronous motor. so even with severe temp swings a quartz beat everything but atomic clocks.
a quarts clock has a frequency of 32,000+ hz and oscillates at 215 cycles per second. they lose less than half a second a day.
temp variations will not let a quartz deviate anywhere near as much as the absolute attainable accuracy of a synchronous motor. so even with severe temp swings a quartz beat everything but atomic clocks.
(Edited 2 minutes later.)
squeegee double-posted this 11 years ago, 1 minute later, 4 hours after the original post[^] [v] #603,282
@603,278 (E)
only if it's using a quartz oscillator, which anything made after the 70s is practically guaranteed to.
only if it's using a quartz oscillator, which anything made after the 70s is practically guaranteed to.
Metæ (OP) replied with this 11 years ago, 3 minutes later, 4 hours after the original post[^] [v] #603,285
@603,273 (squeegee)
> even the cheapest quarts jobs are more accurate than any electric or mechanical system. we went from super high end mechanical (vaccuum chambered) ingvar pendulum clocks, to quartz, to atomic.
What the fuck are you on about? Here's how it works: a synchronous electric clock is powered by a motor that is locked to the line frequency (60 or 50Hz depending on country) at the power company, they precisely control this so it averages out to exactly 60Hz, using high end quartz or atomic.
> even the cheapest quarts jobs are more accurate than any electric or mechanical system. we went from super high end mechanical (vaccuum chambered) ingvar pendulum clocks, to quartz, to atomic.
What the fuck are you on about? Here's how it works: a synchronous electric clock is powered by a motor that is locked to the line frequency (60 or 50Hz depending on country) at the power company, they precisely control this so it averages out to exactly 60Hz, using high end quartz or atomic.
Syntax replied with this 11 years ago, 16 minutes later, 5 hours after the original post[^] [v] #603,299
AC line frequency does vary a bit and is corrected so that at the end of every hour on average a clock running on a Synchronous motor wood be vary accurate.
Early days of Quartz crystals - Methods to crack out cheep production units were temp and pressure sensitive - Take a clock from my Ocean a Blue location to say Colorado and its not going to end up with same time.
But sure I wood expect after the bugs were worked out by the 90's for Quartz to be the only way to go. I used to etch my Quartz crystals for spot on frequency. Hydrofluoric acid. I never ever got down to cutting my own Quartz nor new anyone who tried other then the place I used to go to buy them from - a factory in Los Angeles. Many variations on cutting much like a diamond for different physics results.
Early days of Quartz crystals - Methods to crack out cheep production units were temp and pressure sensitive - Take a clock from my Ocean a Blue location to say Colorado and its not going to end up with same time.
But sure I wood expect after the bugs were worked out by the 90's for Quartz to be the only way to go. I used to etch my Quartz crystals for spot on frequency. Hydrofluoric acid. I never ever got down to cutting my own Quartz nor new anyone who tried other then the place I used to go to buy them from - a factory in Los Angeles. Many variations on cutting much like a diamond for different physics results.
squeegee joined in and replied with this 11 years ago, 32 minutes later, 5 hours after the original post[^] [v] #603,316
@previous (Syntax)
i work with a guy who helped develop the modern quartz crystal. it's incredibly tiny and shaped like a tuning form. One of his colleagues was at lunch with the head of the company and they were talking quartz oscillators (which at the time were flat and subject to wild swings in accuracy due to even small temp variations.) They were talking about how "curving" the crystal makes it less likely to warp, and the dude said, "too bad we can't curve them into the shape of a tuning fork, because tuning forks are super resilient to frequency oscillations (or something like that) and the Boss jumped up and called him a genius and put him in charge of making it happen. The guy i work with was one of the engineers who created the process for making small quartz tuning forks.
and yeah, a 60hz synchronous motor is very accurate, but it pales in comparison to quartz accuracy. clock timing is all about period and rate, and the higher the rate the more accurate the device. you're right, old style quartz was bad, but it was still more accurate than a 60 cycle motor (all things being equal, including temp.) it's the whole reason that you can't even find electric clocks with synchronous motors anymore except in rare instances. quartz dominates day to day time, as it should, because it's super reliable, cheap, accurate, and small.
unfortunately mechanical (and electromechanical) clocks are just dinosaurs and have been for many decades. one thing about the 60 cycle synchronous motors though is that (you're right) they are very stable in their time keeping. temp changes don't have any real effect, but temp can make a mechanical clock vary by as much as 10 minutes due to average indoor temperatures (think summer months vs winter months). quartz clocks are actually a lot more resilient against temp variations now compared to 40 years ago because of the manufacturing process, and since then the only clocks to ever beat out quartz have been atomic clocks for accuracy, but still nothing tops quartz for both accuracy and price.
they DO lack ruggedness, though, because they are so cheap. but, they are replaceable AND cheap, so it doesn't matter much how long a quartz mech will last.
but yeah, modern quartz clocks (like anything from the last 40 years or so) has a very, very large range of operational temperatures before you see any effect on the actual rate of the clock
i work with a guy who helped develop the modern quartz crystal. it's incredibly tiny and shaped like a tuning form. One of his colleagues was at lunch with the head of the company and they were talking quartz oscillators (which at the time were flat and subject to wild swings in accuracy due to even small temp variations.) They were talking about how "curving" the crystal makes it less likely to warp, and the dude said, "too bad we can't curve them into the shape of a tuning fork, because tuning forks are super resilient to frequency oscillations (or something like that) and the Boss jumped up and called him a genius and put him in charge of making it happen. The guy i work with was one of the engineers who created the process for making small quartz tuning forks.
and yeah, a 60hz synchronous motor is very accurate, but it pales in comparison to quartz accuracy. clock timing is all about period and rate, and the higher the rate the more accurate the device. you're right, old style quartz was bad, but it was still more accurate than a 60 cycle motor (all things being equal, including temp.) it's the whole reason that you can't even find electric clocks with synchronous motors anymore except in rare instances. quartz dominates day to day time, as it should, because it's super reliable, cheap, accurate, and small.
unfortunately mechanical (and electromechanical) clocks are just dinosaurs and have been for many decades. one thing about the 60 cycle synchronous motors though is that (you're right) they are very stable in their time keeping. temp changes don't have any real effect, but temp can make a mechanical clock vary by as much as 10 minutes due to average indoor temperatures (think summer months vs winter months). quartz clocks are actually a lot more resilient against temp variations now compared to 40 years ago because of the manufacturing process, and since then the only clocks to ever beat out quartz have been atomic clocks for accuracy, but still nothing tops quartz for both accuracy and price.
they DO lack ruggedness, though, because they are so cheap. but, they are replaceable AND cheap, so it doesn't matter much how long a quartz mech will last.
but yeah, modern quartz clocks (like anything from the last 40 years or so) has a very, very large range of operational temperatures before you see any effect on the actual rate of the clock
Syntax replied with this 11 years ago, 39 minutes later, 6 hours after the original post[^] [v] #603,330
@previous (squeegee)
Most people currently use their cell phone for a hands on clock. 4G LTE base stations have to be accurate to +/- 50 parts per billion. Its just strange that only recently the phones have been able to actually display time with such accuracy. Lots of odd reasons including Iphone errors when it should have been so simple to just sync on the base station time. I am not supposed to say a lot about current issues. Its the transition from back hauls that used T1 lines which include a super accurate sync source to the land line phone company back haul. Clocks of the best Atomic clock type.
Currently Ethernet issues are just that but still a few digits on the phone face can be ultra accurate. Part of the last few years errors on cell phones ends up with over integration of GPS features.
GPS in space has on board Atomic clocks and in theory was supposed to be the most accurate source of delivering such accuracy to the end user. In theory only LoL.
I in no way as a consultant on cell systems make Time accuracy part of my area of expertise. I just read the system error reports and continue to laff about how often carriers get it wrong. To be fair there are still difficult problems to be agreed upon for solution. Tied to the land line phone system made it simple. Untied makes it more difficult.
I should add. Its not that the Cell carriers are all that interested in delivering a accurate time to the end user. That +/- 50 parts per billion has everything to do with issues like dropped calls and quality hand offs that end up in dropped calls and currently a lot of garbled audio.
Most people currently use their cell phone for a hands on clock. 4G LTE base stations have to be accurate to +/- 50 parts per billion. Its just strange that only recently the phones have been able to actually display time with such accuracy. Lots of odd reasons including Iphone errors when it should have been so simple to just sync on the base station time. I am not supposed to say a lot about current issues. Its the transition from back hauls that used T1 lines which include a super accurate sync source to the land line phone company back haul. Clocks of the best Atomic clock type.
Currently Ethernet issues are just that but still a few digits on the phone face can be ultra accurate. Part of the last few years errors on cell phones ends up with over integration of GPS features.
GPS in space has on board Atomic clocks and in theory was supposed to be the most accurate source of delivering such accuracy to the end user. In theory only LoL.
I in no way as a consultant on cell systems make Time accuracy part of my area of expertise. I just read the system error reports and continue to laff about how often carriers get it wrong. To be fair there are still difficult problems to be agreed upon for solution. Tied to the land line phone system made it simple. Untied makes it more difficult.
I should add. Its not that the Cell carriers are all that interested in delivering a accurate time to the end user. That +/- 50 parts per billion has everything to do with issues like dropped calls and quality hand offs that end up in dropped calls and currently a lot of garbled audio.
Anonymous B replied with this 11 years ago, 2 minutes later, 6 hours after the original post[^] [v] #603,336
Syntax replied with this 11 years ago, 2 minutes later, 6 hours after the original post[^] [v] #603,338
squeegee replied with this 11 years ago, 12 minutes later, 6 hours after the original post[^] [v] #603,346
@603,330 (Syntax)
actually something i wonder is if cell phones have a quartz crystal in them for the clock. i mean every single computer has a quartz crystal in them, so i'd guess they do. lots of quartz clocks now have a small radio receiver and they pick up the signal out of boulder and sync to the second (and then run normally with the quarts crystal.) as long as it syncs once every day then it'll maintain second accuracy. microsecond accuracy, man, that would need a lot more syncing. so if quartz is +/- 1 sec a day that's 1000 microseconds a day variance. so you'd need to sync it maybe 1000 times a day to stop variance in the range of microseconds. so if my stoned napkin math is right then you'd need to sync like once every minute and a half to keep a cellphone at microsecond accuracy using a quartz crystal.
probably they sync every time the phone talks to the towers, which is actually very frequent if you've got the phone turned on (even if not in use). but i don't know how often a phone talks to a tower. my brother worked for cingular at one point, he said is almost constant, but not quite. but, if it's more than 1000 times a day then a phone could easily keep microsecond accuracy using just a regular quartz crystal.
edit: googled it, yes, every cell phone has a quartz crystal in it.
actually something i wonder is if cell phones have a quartz crystal in them for the clock. i mean every single computer has a quartz crystal in them, so i'd guess they do. lots of quartz clocks now have a small radio receiver and they pick up the signal out of boulder and sync to the second (and then run normally with the quarts crystal.) as long as it syncs once every day then it'll maintain second accuracy. microsecond accuracy, man, that would need a lot more syncing. so if quartz is +/- 1 sec a day that's 1000 microseconds a day variance. so you'd need to sync it maybe 1000 times a day to stop variance in the range of microseconds. so if my stoned napkin math is right then you'd need to sync like once every minute and a half to keep a cellphone at microsecond accuracy using a quartz crystal.
probably they sync every time the phone talks to the towers, which is actually very frequent if you've got the phone turned on (even if not in use). but i don't know how often a phone talks to a tower. my brother worked for cingular at one point, he said is almost constant, but not quite. but, if it's more than 1000 times a day then a phone could easily keep microsecond accuracy using just a regular quartz crystal.
edit: googled it, yes, every cell phone has a quartz crystal in it.
(Edited 1 minute later.)
Metæ (OP) replied with this 11 years ago, 3 minutes later, 6 hours after the original post[^] [v] #603,348
@603,330 (Syntax)
I've noticed my phone (on Sprint 4G LTE) is often a second or two behind NIST time (using a radio controlled G Shock) and then when I restart it it's back on the mark. It seems the phone is only resetting the clock on boot and if left running for a few days will start to drift. I always wear a watch so it doesn't bother me but you'd think a device tethered to some of the best timekeeping on earth would be a bit better than that.
I've noticed my phone (on Sprint 4G LTE) is often a second or two behind NIST time (using a radio controlled G Shock) and then when I restart it it's back on the mark. It seems the phone is only resetting the clock on boot and if left running for a few days will start to drift. I always wear a watch so it doesn't bother me but you'd think a device tethered to some of the best timekeeping on earth would be a bit better than that.
squeegee replied with this 11 years ago, 5 minutes later, 6 hours after the original post[^] [v] #603,352
@previous (Metæ)
interesting, i'm betting that phones only sync time once a day. anything beyond second accuracy has little utility in day to day use. i wonder why yours won't sync up. do you have updates turned off (i have no idea) or run an unusual rom or something?
interesting, i'm betting that phones only sync time once a day. anything beyond second accuracy has little utility in day to day use. i wonder why yours won't sync up. do you have updates turned off (i have no idea) or run an unusual rom or something?
Syntax replied with this 11 years ago, 11 minutes later, 6 hours after the original post[^] [v] #603,357
@603,346 (squeegee)Few seconds b4 I hit the shower and roll out for evening. That Crystal Oscillator is NOT for clock on face of phone. It the local oscillator for the RF subsystems for transmit and receive.
And connect to towers is 1000 times a second or greater Depending on version of phone and 4GLTE - Even back at get go Cingular was over 100 times a second -
@603,348 (Metæ)
Yes as I mentioned many a system wood end up with time displayed not so much so accurate.
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