Rain Detector
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From: Hul Tytus on 28 May 2006 19:14 Steve - what's the depth of the tank? ie 1mm in what total? For a possible start, a double sided pc board cut to 10mm by ?mm (radio shack?) with a capacitor, inductor & transistor soldered on and some paint should give you first info. Keep in mind that the dielectric constant of water is around 70 & epoxy board material is about 4 (check both). Hul Steve <steve(a)deletethissjwilliams.com> wrote: > On Fri, 26 May 2006 14:43:47 +0100, "Tom Lucas" > <news(a)REMOVEautoTOflameREPLY.clara.co.uk> wrote: > >As for the detection, the water level detection in the Industrial Boiler > >Control I'm working on uses capacitance probes and is pretty sensitive. They > >work by using an oscillator whose frequency varies with the capacitance of a > >probe dipped in the water. Measure the frequency - know the depth. > Picking up on this point - I'm interested in making an accurate > aquarium level detector at the moment (saltwater) , and wonder how > good this method could be. In an ideal world something like 1 mm > resolution would be good. Could this method achieve this. Any > suggestions on the general type of oscillator and ballpark frequency > that might work best? > Steve
From: purple_stars on 28 May 2006 22:56 scilent-project wrote: > Hi > For final year project,I want to design a rain measurement device which > can be read through parelle port of a PC. > All ideas on this topic are cordially welcome. > > thanks in advance. biological control unit, definitely. use a pic with usart, program that and hook it up to the pc serial port via a long serial cable that goes outside on the front porch. use level converts so you get a good distance on the cable. attach the pic to a switch. when the switch is activated that sends a signal to the pc that does whatever you want it to do. set a big glass of tea on the porch to attract control unit (i.e. your mom) out on the porch. when she sees rain she pushes the button. alternatively, for more fidelity, you could have a pot and use a/d conversion to get a range of values. label the pot something like "ain't raining", "ain't much rain", "little bit a drizzle", "it's rain'n perty good", "raining a lot", "cats and dogs", and "i think i just saw toto". then instruct control unit about the finer points of polling vs. interupt driven i/o and instruct control unit to periodically poll (i.e. look) and see how much rain there is and to use the pot to select the proper value.
From: Steve on 29 May 2006 08:36 On Sun, 28 May 2006 23:14:53 +0000 (UTC), Hul Tytus <ht(a)panix.com> wrote: >Steve - what's the depth of the tank? ie 1mm in what total? > Thanks, it's a pretty shallow tank, about 30cm. I'd need to make a non-copper electrode design for this as there are inverts in there. I was thinking about a stainless probe or pair of to do the sensing. Steve
From: Hul Tytus on 29 May 2006 18:43 Steve - what are inverts? Hul Steve <steve(a)deletethissjwilliams.com> wrote: > On Sun, 28 May 2006 23:14:53 +0000 (UTC), Hul Tytus <ht(a)panix.com> > wrote: > >Steve - what's the depth of the tank? ie 1mm in what total? > > > Thanks, it's a pretty shallow tank, about 30cm. I'd need to make a > non-copper electrode design for this as there are inverts in there. I > was thinking about a stainless probe or pair of to do the sensing. > Steve
From: Steve on 29 May 2006 20:07
On Mon, 29 May 2006 22:43:55 +0000 (UTC), Hul Tytus <ht(a)panix.com> wrote: >Steve - what are inverts? > Ah, a bit OT I guess, but invertebrates, as in non-vertebrate organisms, include corals and other non-fish marine things - hence the need for precise level (== water specific gravity) control to keep them. Copper in greater than trace concentrations is highly toxic to marine invertebrates, hence you need to avoid same in any electronics in contact with aquarium saltwater. Steve |