The "firecracker" can only send on/off or bright/dim codes (though
far more that just the std. X10 house/unit codes which are documented online).
An MR26 would be better choice than a CM11 -- he'd get the output directly
into a serial port (and it IS easy to improve the receiver antenna) in an
easy to parse format. But, ... you'd have to make up some signaling format
for analog data given unreliable single bit messages (or try using the
modified MR26 PIC from mbx-usa.com with one of their transmitters and a
BS/PIC/Atmel uC. to interface to the sensors). You are correct, though,
that with a BS (or a PIC) he can find an existing serial implimentation
which will talk to the firecracker (free, but $5.90 shipping - if you use
the correct ordering code).
With your CM11 idea, he'd also need a RR501, TM751 or equivalent
too. And the CM11 protocol is much more complex than either the original
CM17/MR26 (RS232), MR19 (USB w/ camera base protocol support) or the
"Dave Houston" modified MR26 (still RS232, but a "simpler" output format
and no filtering - the MR26 normally drops many codes - i.e. doesn't report
them to the computer port), and he doesn't need the powerline path leg
involved. Basically, with a CM11a solution (assuming an ActiveHome kit
with both the CM11a and a TM751, instead of purchasing them seperately
for ~$12 more) you're at about $70 before starting to solve the problems
w/ std X10 RF or getting the BS kit (about $50) -- a MR26 only saves about
$25 (costs $25 or less in combination with other "junk") and a modified PIC
would set him back another ~ $10 w/ shipping.
I'm sure there are similar, but cheaper and simpler methods
available. ex. Directly bit bang a SAW transmitter from a uC (don't
go up to RS232 then RF then powerline then back to RS232 again), but
receive using some inexpensive "home-automation" type device or commercial
ASK receiver and another uC (though, if he can use the frequency, a MR26 is
$25, RS232 and simple to hook to a computer - the MR19 is $50, USB and a
little tougher - the codes are undocumented, but trivial to determine).
paul shupak
>From [EMAIL PROTECTED] Wed Jul 21 21:12:03 2004
>From: "John W. Palmieri" <[EMAIL PROTECTED]>
>To: [EMAIL PROTECTED]
>Subject: Re: [SOCALWUG] Wireless sensors
>Date: Wed, 21 Jul 2004 20:49:03 -0700
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>On Wednesday 21 July 2004 20:22, Dave Close wrote:
>> ... I'd like to set-up a small network of battery
>> operated sensors which can report back to a server wirelessly.
>
>One idea:
>
>Client -- use a Basic Stamp experimenter's board, your
>temperature sensor, and an X10 Firecracker module. The ID would
>be hardcoded in software in the Basic Stamp EEPROM. In bulk I
>imagine you could hit your price point.
>
>Server -- X10 receiver and CM11 module to read the codes sent.
>
>You could encode the data using the X10 commands. Lots of
>issues, but an idea.
>
>Cheers,
>John
>--
>John W. Palmieri
>eMail: john at mediaonfire dot com
>
