[time-nuts] help

jimlux jimlux at earthlink.net
Mon May 2 08:55:15 EDT 2016


On 5/1/16 6:30 PM, Chris Albertson wrote:
>> But are you sure you want SMPTE... Do you have a source already?
>>
>>
> You don't need GPS or SMPTE if you have an Internet connection.  The
> computer can use a set of NTP servers from the "pool" to get time.  The
> result is good enough that the seed of sound delay resulting from your
> random distance to the bell will be the largest source of error.
>
> If you convert timing errors to distance at the speed of sound.   You would
> need the GPS only if you car about bell to ear distances of about one foot,
> give or take
>
> So for this use case the OP does not need a GPS or even a SMTPE connection
> just a WiFi link to the internet would be more than enough for controlling
> a horn blast from a light house
>
>


However, depending on how much work you want to do, it's easier to 
decode the serial stream from a GPS receiver or SMPTE and close a relay, 
than it is to set up an internet connection, make sure it's not 
vulnerable, etc.etc.etc.

If you already have a PC with a connection, sure, it's straightforward, 
but if you're starting from scratch, the work to get the whole internet 
software stack up and running particularly on a small cheap board is 
substantial.

If you already have a Arduino/Beaglebone/Rpi set up, and safely 
connected to the internet, then you could just copy that; but if you've 
not done it before, it takes a while.




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