Hi Neville, As a thought, you might want to look at a Basic Stamp from Parallax. These are PIC chips (at least they used to be) coupled with an EEPROM and are programmed in BASIC. Here's a site for some additional data -
http://www.parallax.com/Default.aspx?tabid=295 Regards, Bruce Raymond Neville Michie wrote: > My pendulum produces pulses at a rate of one per second. > That signal clocks a latch that samples the less significant bits of > my reference oscillator (100kHz or 1MHz) > in a counter. > The latched values drive a 12 bit D-A converter (a R - 2R chain). > So I have a phase signal updated every second, and which resolves 10 > or 100 microseconds. > The data logger samples this every 10 seconds or so and so logs a > graph of drifting phase. > The data from the logger can then be used in a spread sheet to > analyse periodicity > of fluctuations and correlation to barometric pressure and temperature. > When barometric pressure and temperature are successfully eliminated > by compensating > the pendulum, I hope to only have planetary resonances, gravity tides > and noise disturbing my clock. > Currently I have a 1MHz OCXO driving the system, but it drifts > significantly. > This is a home brew oven, running at about 40*C, consuming about > 250mW, quite easy to > back up with a 12V battery. > The HOBO data logger has 4 inputs of 0 - 2.5 volts and 12 bit > resolution, and it runs > for 4 years on a lithium cell. > It takes a lot more power to run a computer, and then you have to > reboot after each power > interruption, and so I have not found it worth while to get a machine > just for the project. > > But the overall check of the system is to compare clock time with UTS > once in a while > to cover the chance of slipped seconds. At the present time I use WWV > when I can find it, > but what I would really like is a clock showing UTS in a form that > can be compared to a clock. > That means one second audible pips and a marker on the minute. Just > seeing numbers > rolling over on a computer is not good enough to check the timing of > the second hand of > the clock. You need ear - eye coordinated signals. With WWV I can > compare to 1/20th of a second. > > Although I have programmed systems in a variety of languages in my > working life, the only > languages that have stuck are Fortran and Basic. All the rest are > forgotten after a year or two. > I do not wish to start again to learn a new system just for one task, > and it is obvious that there > are so many micros abroad and none of them is going to be universally > useful for future tasks. > > cheers, Neville Michie > > _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
