Re: Ceiling Fan RF Remote Compatibilty

[nobody@xxxxxxxxxxxx (Dave Houston)]

Just Another Joe <address@xxxxxxx> wrote:

>Hi Dave.  Yes, I hope to build the transmitter portion to allow the
>Ocelot to control the fans.  Right now, the Ocelot can do so by sending
>IR to the hand-held remote control, using a small interface that Guy
>designed.  But I hope to use one of those small transmitter modules to
>free up the hand-held remote.

Look at the datasheet for whatever transmitter you choose. It should have
data rates for ASK and OOK modulation. This application uses OOK. Here's the
datasheet for one such transmitter.

     http://www.wenshing.com.tw/english/prouducts_info.asp?bookbm=170

the OOK data rate is 2.4Kbps which is far below the 38kHz IR signal. The
transmitter will operate exactly the same whether you drive it with a
baseband (unmodulated) signal or with the IR signal.

Philips Pronto double modulates its RF signal, sending bursts of 418 or 434
MHz RF modulated at 38kHz and the uses an Atmel U-2538B chip in the
receiver. This means the receiver will ignore any RF that is not modulated
at 38kHz. This requires a fairly sophisticated receiver. The
superregenerative receivers used in the fans will not respond fast enough to
even see the 38kHz and will respond in the same way as if the RF was only
modulated by the baseband data signal.

http://davehouston.net
http://tech.groups.yahoo.com/group/roZetta/
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