[time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?
Nick Sayer
nsayer at kfu.com
Wed Oct 25 00:04:01 UTC 2017
FWIW, I’ve documented the whole R-Pi GPS NTP thing at https://hackaday.io/project/15137
As a disclaimer I will also say that I’m not even remotely the first. But what’s kind of nice is that I have a R-Pi desk clock display board that plays really well with a bolt-on GPS cap. In fact, I’ve got two of them in the NTP pool right now.
Sent from my iPhone
> On Oct 21, 2017, at 7:50 AM, ROY PHILLIPS <phill.r1 at btinternet.com> wrote:
>
>
> ----Original message----
> From : hmurray at megapathdsl.net
> Date : 21/10/2017 - 7:49 am (GMTDT)
> To : gem at rellim.com
> Cc : time-nuts at febo.com, hmurray at megapathdsl.net
> Subject : Re: [time-nuts] inexpensive, black box, GPS or NTP based TTL time capture?
>
>>>> For under a $100 you could get a Raspberry Pi, a GPS HAT, and
>>>> connect your input to a GPIO pin. Configure ntpd to log the real
>>>> PPS and the input as another 'PPS'.
>
>>> Is there an option to log all individual PPS events?
>
>> # ppswatch /dev/pps0
>
> That's a way to log stuff, but I don't think it comes under "Configure ntpd".
>
> I remember some option to log lots of stuff, but I don't remember the
> details. It could have been in a driver. I couldn't find it in the man page
> for the PPS driver.
>
> [amazon]
>> Looks like $96 to me. You can save some if you buy in bulk,
>
> You can save $7 if you get the starter package that has only Pi, SD card,
> power, and case. (Many starter packages include stuff you probably don't
> need and that raises the price. But maybe one has a HDMI adapter. I didn't
> look.)
>
> Beware of using normal USB cables and/or normal USB power supplies. The Pi
> is not happy with low voltage. The drop in a USB cable can be significant.
> The setups intended for use with Pis normally have 5.1 or 5.25 volts and
> heavier gage wire in the cable.
>
>
> [display, kbd, mouse...]
>> Yeah, just for setup. Shall we include the price of the desk it sits and
>> the building it is in?
>
> I'm willing to assume somebody has a table and a roof.
>
> The display and such are not a problem if you have a PC you can borrow them
> from. (You probably need a HDMI adapter.) But that doesn't work if all you
> have is a laptop or smart phone.
>
> I think most of my friends have PCs but I wouldn't be surprised if some of
> them had a laptop and no PC.
>
> If your PC is old enough, the keyboard and mouse may be PS2 rather than USB.
>
>
> --
> These are my opinions. I hate spam.
>
>
>
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