[time-nuts] accurate portable time source
brooke at pacific.net
Sat Dec 29 17:24:14 EST 2007
The last LCD clock I made had the pads for a DS3231 but for various reasons I
never installed it. http://www.prc68.com/I/PRC68COM.shtml#07092006
http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam
Ronald Held wrote:
> You have been thinking about this longer than I have. I presume you
> have not tried to make any prototypes?
> Message: 1
> Date: Fri, 28 Dec 2007 15:19:49 -0800
> From: Brooke Clarke <brooke at pacific.net>
> Subject: Re: [time-nuts] accurate portable time source
> To: Discussion of precise time and frequency measurement
> Message-ID: <47758495.7070707 at pacific.net>
> Content-Type: text/plain; charset=us-ascii; format=flowed
> Hi Ronald:
> Here are a some of ideas for the heart beat for a LCD based clock like the ones
> I've been developing.
> Best) A Vectron EX-380 series Vacuum OCXO only draws 0.35 Watts and if the 5
> volt version that's only 70 ma. So a single AA would have enough energy, three
> AAA Ni-MH would be great. That was the good news. The bad news is that they
> are made of unobtanium (i.e. very expensive or need to be bought in large lots).
> Good) An alternative is the DS3231. This is an advanced version of the DS32khz
> TCXO and is adjustable to 0.1 ppm using the digital serial interface.
> Provision for a coin cell back up battery.
> unknown) One of the DS3231 parts, in a thermal enclosure that has a time
> constant in excess of 24 hours. I think it's about the size you request. A
> temperature sensor changes the divisor based on calibration data. Sort of a
> doubly compensated device TTCXO or T2XO. I like this one for a
> practical product.
> Have Fun,
> Brooke Clarke
> http://www.prc68.com/I/WebCam2.shtml 24/7 Sky-Weather-Astronomy Cam
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