Hi Nigel,
Ive spent some time going over your site, sites as there seem to
be two. And yes, i am beginning to think that you are right, using
tape cassettes may not be the best way to deal with this project.
You also mention that i wasn't clear about what it is that i am
intending to sample. Thats true, so i will try to set out what i
want to do in general terms.
Around my home i have placed a few sensors over the years, some
years ago the water pipes froze in my attic during a very cold
spell and split open a couple of joints.
I was very fortunate on that instance as the situation could have
easily been much worse. The freeze up must have happened during
the night, and when i got up later on, the attic pipes were still
frozen, but the water feed downstairs was ok, so all seemed well
and i didn't notice anything amiss. Until i washed up some dishes,
the hot water from the tap was not coming out at its usual rate,
and seemed to be reducing. After a short while it was down to a
dribble, yet the rising main was fine and normal. So i checked it
out, and found that the attic water tank that feeds the hot water
system was empty, with a layer of ice across the top where the
water surface is usually, holding the ball-co ck closed, sitting
there like a sheet of glass with the ball-co ck embedded in it.
Well i didn't just break the ice, and hope all would be well, as i
have met this sort of thing before.
I had a good look around at the pipes, and the fittings, and soon
saw that a couple of joints were damaged.
This annoyed me cos i knew that as soon as things warmed up during
the day, they would become fountains of water unless i turned the
water feed to the house off.
So i had to turn off the water feed to the house.
The burst sections were soon dealt with and i fitted an additional
in-line tap in the attic where the rising main feeds the tanks,
so that in future i could keep the water feed to the rest of the
house. Almost no water was spilt into my attic, and i consider
that a bonus, as i keep lots of bits and pieces up there.
So i fitted the first of my 'sensors' into the attic, by the water
tanks. If the temp dropped to almost freezing, a light comes on in
my front room, and also in my bedroom, to let me know.
The following year i fitted up a small fan heater in my attic just
to come on with that sensor, it has only come on once this winter,
and only briefly.
Later i fitted a sensor by my front door, to ring a little bell up
the end of the garden, cos often people would go to the front door
and i didn't always hear the knocker, so if i was in the garden i
would sometimes miss them. That also works a little light in my
front room.
Over the years i have added to the various sensors, and for a while
i have been thinking of making some sort of logging for them.
Such logging need only be pretty basic, if a fairy were to make
notes for me, they only need to be something like this:
02 on 14:25 11/1/04
04 on 17:00 11/1/04
04 off 17:00 11/1/04
and so on, just a list of numbers and date/times with on or off.
Since i have box-loads of cassette tapes, i was thinking of using
them as logging records thinking that maybe a year would probably
fit on to each cassette.
However since reading some of your stuff about making a CMOS clock
and building a system using a Programmable Controller, and EEPROMs
which i think means Electrically Erasable Programmable Read Only
Memories, i realise that it can of course be done completely using
chips, and probably also a small display to set things like clock.
But what would i keep the log records on ?
Maybe i could transfer them to PC, keep them on a floppy ?
One of the things with using cassettes is that they aren't the usual
PC media, well not for years anyway, and they are very unlikely to
be used for anything else, they can sit there on a shelf with dates
on and not get disturbed.
Still maybe for those few bytes per instance, a floppy might hold
many years worth so that would be easy enough to keep safe.
No i am not dead set on using tape cassettes, or floppies, or any
particular method.
At one stage i looked into using a dot matrix printer, cut down to
use a roll of paper about an inch and a half wide, like a till-roll
so that the printer would print a line each time a sensor gave out
a signal, the paper roll would be the record, and the PC would not
be part of such a system. This method still appeals to me, but if
there are easier or cheaper ways then of course i would like to
know.
I hope i have put enough information to illustrate adequately the
intention of this project.
*******************
*******************
Hi Someone Electro,
Thank you for your input, i do have many tape recorders of many types
and yes i had considered using a tape cassette unit for this project.
If i went down that route, it would probably mean leaving the unit
in the record position and switching it on and off by its supply. So
long as the pinch wheel is not unreasonably tight, some of them are,
then the tape does not get damaged in my experience. I would allow
between a half and a full second to reach running speed, and i would
reckon about a second to about one and a half seconds to record the
bleeps (signal).
I had intended that the tape could be read into a Windows PC using a
normal cassette unit and a lead made to fit between the two, i was
guessing that a bat file could copy to a text file for perusal.
I have not done any of this yet, i am still looking at possibilities.
As for the modem comment,
it occurred to me that if the audio signals from the tape,
were the same as the audio signals that come down the phone line,
then the modem on the PC might be able to deal with them easily.
That was what i meant.
However, it might be much easier to put together a different system
entirely, it might be possible to make a unit that will record the
signal information directly on to a floppy disc.
This could easily be read on a PC, without any special arrangements.
I am quite happy to use a spare floppy drive for this if need be.
Thank you both for you interest and suggestions,
Which way to you think i should go from here ?
John
