OK - here is my Sundial project. Not existing - something for my retirement:: 2 photodetectors behind a lens with a tube are mounted on a disk that can rotate horizontally. Functionally you can say it is rotated by a stepper motor; one turn per day (I actually have another Very low-power idŽa in mind). The sun would give equal light to the photodetectors when the lens with tube is aimed towards the sun. When off balance, the steppermotor would give it a nudge to line up again. A dial indicating time is attached to the disk. At sunset, the stepper motor would swing around to wait for the sunrise again - quickly before a "power-capacitor" discharges (avioding NiCad's). And go beddibyes. All solar powered - of course :=) Sven -----Ursprungligt meddelande----- FrŚn: Harold Hallikainen Till: PICLIST@MITVMA.MIT.EDU Datum: den 7 maj 1999 00:17 €mne: Re: Weird, Wacky, Zany PIC applications >On Thu, 6 May 1999 08:58:50 +0100 Brian Jones >writes: >>Not my idea I'm afraid but also check out the June 99 (yes - it >>came out last week!) edition of the UK magazine Everyday >>Practical Electronics. >> >>It has a PIC based sundial. When the shadow drops over one of the >>hour markers the hours pip and the tune 'You are My Sunshine' >>plays. Looks like a few other fun features also. Probably not up on >>their website yet but their normal practice is to make the source >>code available for FTP. >> >>Brian >>Brian E Jones >>Centre for Java Technology >>IBM HURSLEY >> > > > Neat project! Especially the "You are my sunshine" part, which >is a favorite with my wife. Anyway, I can see how this project could be >struck by creeping featurism... It could be a sundial with a digital >display where there's a "noon detector" that sets a calibration factor >for the processor clock so it can correctly time the rest of the day and >night. Although a bit more difficult, it appears there could also be a >shadow length detector which could be used to determine the date and >latitude (given enough time for the shadow to reach its maximum length). > Some interesting stuff on clocks and the measurement of time is >in the book "The Discoverers." As I recall, the original mechanical >clocks had 12 hours from sunrise to sunset, but they had to keep being >adjusted since the amount of "time" between sunrise and sunset varied. >They came up with elaborate mechanical methods to automatically adjust >the clock before finally coming up with the idea of letting there be time >after sunset and allowing the sunrise and sunset times to vary. > > >Harold > > > > >Harold Hallikainen >harold@hallikainen.com >Hallikainen & Friends, Inc. >See the FCC Rules at http://hallikainen.com/FccRules and comments filed >in LPFM proceeding at http://hallikainen.com/lpfm > >___________________________________________________________________ >You don't need to buy Internet access to use free Internet e-mail. >Get completely free e-mail from Juno at http://www.juno.com/getjuno.html >or call Juno at (800) 654-JUNO [654-5866] >