Re: Looking for Temp and humidity sensors

[nobody@xxxxxxxxxxxx (Dave Houston)]

That shoulda said "disruptions". Dunno how that happened.

nobody@xxxxxxxxxxxx (Dave Houston) wrote:

>Sure. One could design a more functional Bobcat (e.g. SECU16i + temperature
>sensors).
>
>ADI's primary business is contract manufacturing of SMT boards for others.
>If anyone is likely to be efficient, they are. However, Chinese factories
>can do the same work in small quantities for much less. So, design what you
>want and send it off to one of them to fabricate.
>
>I designed a small battery powered generic wireless ADC module using a
>protocol that is understood by the BX24-AHT. It costs less than $10 to make
>and could retail for about $20 but will cost about $6K for the required FCC
>ID tests.
>
>The real problem is that *none* of the HA related companies have found much
>of a market. I recall seeing something from Dan Boone about a year ago
>before he left ADI that they had shipped 5000 Ocelots.
>
>Anyone with the skills to roll their own can find inexpensive hardware. The
>JK Microsystems PicoFlash & Pico-I/O can do a lot for about $175.
>
>     http://www.jkmicro.com/products/picoflash.html
>     http://www.jkmicro.com/products/expansionboards/pico-io.html
>
>The $1.60 Insteon PLC chip *might* lead to plug-in sensors of the type you
>want.
>
>Of course, nobody will be able to walk about without causing disputions to
>your readings. ;)
>
>"Robert Green" <ROBERT_GREEN1963@xxxxxxxxx> wrote:
>
>>"Dave Houston" wrote:
>>
>><stuff snipped>
>>
>>> The Bobcat temperature node includes a power supply, an RS485 interface,
>>an
>>> ADC chip (I think they use a PIC but it's been a while since I looked
>>inside
>>> one), an enclosure and an LM34 temperature sensor.
>>>
>>> The Bobcat humidity node includes all of the above but with a Humirel
>>> humidity sensor replacing the LM34. Humidity sensors are not cheap.
>>
>>Too bad.  I see other topologies like Phil Anderson's that make me believe
>>the Bobcats could either be made more functional or less expensive, overall,
>>but I suppose for limited uses where the sensor needs to be bulletproof and
>>highly reliable, the Bobcats make sense.  With 16 port Ethernet hubs going
>>for less than $50 I would have thought we would have seen more things
>>appearing more quickly for networking like remote temperature sensing and
>>even electrical load control.
>>
>>
>>> If you try to duplicate the design you will find that you really cannot
>>> build them and sell them through distribution channels for much less than
>>> what ADI charges.
>>
>><sigh>  And economies of scale never amount to much in small operations like
>>ADI's so the price isn't likely to come down as manufacturing techniques
>>improve.  I wonder if HA will ever see a time where component prices drop
>>the way hard drive prices have for PC's?  X-10 seems to have come the
>>closest in lowering prices through high volume.  It's probably what make it
>>difficult for some people to jump to the next level - almost every other HA
>>control technology is at least double the cost of X-10.  That sets up a
>>mental expectation that it will also be twice as good.
>>
>>> If you already have some type of controller with ADC inputs and a power
>>> supply and a little knowledge you can DIY and save (if you conveniently
>>> ignore the cost of the controller). The cheap sensors need something like
>>an
>>> SECU16 or other controller.
>>
>>It doesn't seem that many people are interested in knowing the temps in each
>>room in the house.  I'm probably just a data freak but it seems to me a home
>>automation system HAS to know details like that to effectively conserve
>>energy.
>>
>>> I think your plans are overkill but you should look at some of the
>>one-wire
>>> interfaces which allow you to network lots of relatively inexpensive
>>sensors
>>> (at least for temperature, RH is still not cheap). You still need some
>>type
>>> of controller or PC to make sense of the data.
>>
>>I just want something simple that can log the temperatures and RH's of the
>>various sensors to an ASCII file that I can analyze later.  If I had the
>>technosmarts to crack the RF protocol of the RatShack remote
>>thermo/hygrometers (six units, three with RH, three without) and record that
>>output to a text file, I'd be happy.  But in reality, I'd like to monitor
>>three temps per room, at least (ceiling, floor and about 3' from the floor.
>>I don't need RH from each room, but I'd like it from critical rooms like the
>>bathrooms, the basement, the pantry, the attic and the kitchen.
>>
>>Why so many sensors?  I believe it will be the foundation of a truly "smart"
>>home that can look for data anomalies and thus detect open windows, clogged
>>furnace filters, improperly operating dampers and a whole host of other
>>things.  A house is like a human being in that it tries to maintain a fairly
>>constant internal environment.  To do that, you have to have lots of sensory
>>input.