Re: Looking for Temp and humidity sensors

[Marc F Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On Sat, 7 Jan 2006 11:23:05 -0800, "Brett Griffin"
<bret.griffin@xxxxxxxxxxx> wrote in message
<MIOdnTVjSb2IiF3eRVn-jA@xxxxxxxxxxx>:

>Basically looking for an low cost sensor either temp only, humidity only or
>combined, commercially available with specs and protocals.
>
>At this point I dont have any requirements, just trying to see what is
>available, so I can determine how I can use them and implement them in a
>upcoming project for a client.
>
>HAI's are fine sensors, but what does everybody feel about the cost, are
>they good, are they high or low?

I have no experience with HAI's sensors and thus no opinion as to whether
they are "good".

But HAI modules are prohibitively expensive for my purposes and budget.

You write "sensor" without elaborating, but it is beginning to seem that
what you want are _modules_ that can communicate rather than a bare sensing
element.

Some very accurate temperature sensors (a silicon diode for example) cost
1/1000th of what I'd speculate that a  HAI temperature module costs  And
calibrated thermistors, Dallas 1-wire devices, and LM34/35's cost on the
order of US$1 and so enjoy about a 40-fold cost advantage compared  to HAI
(and Adicon and ELk and Aprilaire ) temperature _modules_.

Of the humidity _modules_ that I know something about (HAI, Adicon,
Aprilaire/Enerzone) and that are available (Elk's humidity sensors have not
been released yet, but the temperature modules have) I've chosen to use
Aprilaire's because:
	1) they are industry standard for HVAC,
	2) have a publicly available, simple ASCII protocol for
	   communication over RS-485,
	3) are compatible with my existing Aprilaire/Enerzone thermostats
	4) which in turn are supported by all the common HA programs
	   -- but not HAI which has its own stuff to sell.

HTH ... Marc
Marc_F_Hult
www.ECOntrol.org