MSF time signal decoding

Philip · 2004-10-16 22:53

Hi Folks,

I'm so new to this that I don't even know what a stamp looks like so please take it easy on me, I do have one on order though. However, my background is as an audio engineer, I recorded orchestras, so you get the idea :-)

However, I would like to use a stamp to decode the MSF time signal that is broadcast from Rugby in England, I believe there is a version broadcast in the USA called something like WWVB that uses exactly the same format when demodulated.

I can get a device to produce the demodulated MSF signal which seems to be·a serial data stream·and it was my intention of using a stamp to decode this signal into time. However, as this isn't exactly my area I was wondering if anyone has done anything similar or if there is any sample PBASIC code out there that might give me a clue as to where to start? In fact I was wondering if it can even be done?

My cunning plan is, eventually once I get the hang of things, to use this time signal to automatically start video tape recorders capable of remote operation. Clearly I have to work up to that so initially I want to suck the time out of the MSF stream and use it to keep a real time clock accurate. Probably one of these:

http://www.warburtech.com/modules/pocket.watch.b/

Then I want to use a keypad to program alarms into the RTC and then I will use these alarms to drive the stamp to produce the correct sequences to remote control the VTR. I am breaking the process down into steps so decoding the MSF is the first step.

I'd be grateful for any info, ideas or sample code. As yet I haven't got my stamp and so haven't tried writing·any PBASIC but am interested enough such that I'm doing this even though I don't really need to.

Thanks,
Philip.

Jon Williams · 2004-10-17 01:49

If the output from your MSF device is a serial signal at a fairly standard baud and configuration you shouldn't have many problems. Do you have any additional information on the device of the MSF decoder?

If you're just looking to get dead-on accurate time you can also use a cheap GPS unit. Last New Years I made a customized countdown clock that took the time signal from a GPS receiver.

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Jon Williams
Applications Engineer, Parallax
Dallas Office

Philip · 2004-10-17 11:50

Thanks Jon,

I have a device made by Galleon systems called an EM2S which receives and decodes the MSF signal and I also have a PDF which details the format of this signal but, to be honest and in view of my background, I haven't managed to translate that document into English :-) I will attach them in case anyone has any ideas.

In the initial stages I'm going to "play about" writing some code to light LEDs and so on, stuff requiring very little in the way of external devices until I get the hang of the PBASIC.

I believe the task I have in mind can be done as these university students seem to have done something very similar in 1996 but that I can see there is no code indicating how they achieved it, nor no hints of any form:

http://www.doc.ic.ac.uk/~ih/teaching/radclock/96/

There is also a module that can convert the output of the RXer into serial data as shown on this page:

http://www.ntp-time-server.com/wwvb-receiver/wwvb-receiver.htm
(This is the US wwvb version but is the same as the UK version)

Do you think that this serial route might be a better way to go as I could take it directly into the stamp?

I suspect that there may also be a time related newsgroup on Usenet so I'm going to do some searching around in there as well.

Philip.

Jon Williams · 2004-10-17 12:27

We have lots of information that will help you get the hang of PBASIC. Check out our "What's A Microcontroller?" text, and perhaps StampWorks as well. Both are hands-on and should get you up to speed quickly.

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Jon Williams
Applications Engineer, Parallax
Dallas Office

MSF time signal decoding

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